RADAR AND NAVIGATION SIMULATION

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RADAR, ARPA & NAVIGATION SIMULATOR COURSE - THEORY

S.NO SUBJECT LECTURE SIMULATOR PG.NO

(HRS) (HRS)

OPERATE ARPA AND NAVIGATION CONTROLS

1

Demonstrate familiarity with own ship characteristics 1.0 1.0 3-19

1.1
and operate ARPA and navigation controls
2 PERFORM RADAR PLOTTING
2.1 Factors affecting radar plotting are identified correctly 20-29
2.0 4.0

2.2 Carry out radar plotting

3 USE ARPA AND NAVIGATION INFORMATION TO
CONTROL SAFE NAVIGATION AND COLLISION
AVOIDANCE
3.1 Apply COLREGS in open waters in restricted visibility 5.0 19.0
3.2 Plan and control navigation in confined waters
30-58
3.3 Control navigation in/near traffic separation schemes
3.4 Manage a Bridge Team
4 PLAN AND CO-ORDINATE SEARCH AND
RESCUE
4.1 Respond to a distress message 2.0 4.0
4.2 Co-ordinate search and rescue operation 59-90
4.3 Execute a search and rescue operation

TOTAL 10 28

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SIMULATION CONTENTS

S.NO INDEX PAGE NO

1 Simulator Operatations 93
1.1 Design 93
1.2 Procedure for starting the Radar-ARPA Navigation Simulator 93
2 The Navigation Simulator Instructor Station 94
2.1 General 94
2.2 Instructor Console Window 95
2.3 Navigational Scenario 96
2.3.1 Creating an Exercise 97
2.3.2 Saving an Exercise 98
2.3.3 Opening a Saved Exercise 99
2.3.4 During an Exercise 99
2.3.4.1 Changing Target’s Course and speed during an exercise 100
2.3.4.2 Changing Environment Settings during an exercise 100
2.4 Instructor Interrupts 101
2.4.1 Executing the Exercise 101
2.4.2 Controlling Radar Equipment facilities 102
2.4.3 Invoking Failure and Errors 102
2.4.4 Changing Weather Conditions 103
2.4.5 Ending an Exercise 104
3. The Navigation Simulator Student Station 104
3.1 Radar and ARPA Simulator 104
3.1.1 Introduction 104
3.1.2 Controls & Display 105
3.2 Visuals-Cum-Conning Simulator 116
3.2.1 Own Ship Data 117
3.2.2 Conning Panel 117
3.2.3 GPS-1 & GPS-2 118
3.2.4 Auto-Pilot 119
3.2.5 Depth 120
3.2.6 Visual Bearing 121
3.2.7 Binoculars 121

3.2.8 Ship Info 121

3.2.9 Panning View (360 deg) 122

3.2.10 Telegraph 122

3.2.11 Rudder 122

3.2.12 Gyro Compass 123

3.2.13 Course Recorder 123

3.3 Electronic Chart System(ECS) 124

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CHAPTER 1

OPERATE ARPA AND NAVIGATION CONTROLS

1.1 DEMONSTRATE FAMILIARITY WITH OWN SHIP CHARACTERISTICS AND
OPERATE ARPA AND NAVIGATION CONTROLS

RADAR FACILITIES

 Detect by transmitting microwave pulses and receiving reflections from contacts

 Range Measure time for a pulse to hit contact and return to receiver.
o Distance = (Speed x Time) / 2
 Bearing The angle of the rotating scanner (24 rpm

RADAR FACTS

 Target size depends on pulse length(duration of echo) and beam width.

 Radar may not show everything you can see.
 Radar may show you things you cannot see.
 The movement of echoes and tracks on the screen may show up differently to the movement of ships
on the water

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OPERATION

 Pulse is very high energy

 Return echo is very low energy
 Receiver must be very sensitive, so it must be switched off when a pulse is sent
 Objects at very close range not detected
 Approx 30m short range, 250m long range
 Radar listens for 99.9% of the time
 All the echoes from one pulse must be returned before another pulse is sent

SWITCHING ON AND SETTING UP

Power / transmit

 Power - warm up time (2 minutes for magnetron)

 Standby (also Watch mode)
 Transmit – TX

Main controls - B G R T

 Brightness of image
 Gain - amplifies the weak return signal, causes ‘speckle’.(Contrast - if present)
 Range - alters range rings and varies pulse length and interval.
 Long range = long pulse at long intervals.
 Tuning - matches frequency of sent and received pulses. Need a target to tune on - use sea clutter

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UNDERSTANDING THE RADAR PICTURE

Targets on screen

 May be large, small, bright or faint depending on size, orientation, material, surface and range.
 Small boats and buoys may vary in return and disappear for a time.

Target controls

 Interference Rejection - reduces mutual radar interference when two boats with radar are close.
 Normally switched on, but if switched off will show the presence of the other boats.
 Expansion or Echo Stretch- expands target returns; easier to see target but reduces range accuracy.
 Wakes - shows approx direction and speed of a moving target. Duration of wakes may be varied.

CLUTTER

Clutter’ is real echoes returned by targets which are by definition uninteresting to the radar operator. These
include natural objects such as sea, rain, fog, and atmospheric turbulence. Sea clutter from close waves has
multiple small echoes at short range which are not consistent in position, and may form a solid disc in rough
sea states. Rain clutter form large hazy areas. More pronounced on X Band radar. The clutter echoes can be
reduced with clutter controls, but this may also eliminate real targets.

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Sea Clutter

 Sea Clutter - reflections from close waves form an irregular blob at centre of picture
 Clutter increases with wave height and scanner height
 More to windward than leeward
 3 cm radar – more clutter than 10 cm
 Long pulse length – increases number of echoes displayed

Rain Clutter

 Heavy rain reduces range by 50%;fog by 30%

 Suppression
 Difficult with X band, as water is very absorbent to microwaves at this frequency
 Reduce pulse length (range) to reduce rain echoes
 Use long pulse (range) to search for targets beyond the rain

Range Controls

 Always start with sufficiently high range

 Adjust range periodically
 Short range - short pulses, high repetition frequency - higher definition
 Long range - long pulses, low repetition frequency - lower definition

Accuracy of Range

 Short pulses measure range with more accuracy

 Long pulses travel further, but they can merge in the return echo
 Long range = Low Pulse Repetition Frequency; To increase range - longer pulse, longer PRF
 Range Control does this automatically

False Radar Images

 Obstructions on your boat - blind arcs

 Radar cannot see round corners
 Shadow areas - small objects merge with large objects
 Side lobes produce echoes from good reflectors
 Double reflection produces second image at twice the range

HEAD UP

 Heading marker is boat’s heading

 Best for collision avoidance
 Picture moves as boat yaws

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NORTH UP

 True North upwards

 True Motion
 Stabilized
 Like a chart
 Best for navigation
 Parallel indexing

COURSE UP

 Stabilized
 More stable than Head Up
 Picture takes time to settle

Radar displays are categorized according to the motion they generate and the stabilization input. The motion
could be relative or true. Stabilization is further subdivided into course and speed. Comparison is attempted
through use of sketches and tabular list of advantages on left and disadvantages to the right.

RELATIVE MOTION

This display provides an immediate indication of risk of collision or closet point of approach. The display
usually originates from the centre, but off-centre usage is possible with head-up and north-up modes. Fixed
objects generate echo movement in the direction reciprocal to ship’s ground track. Echo blur or smear does
occur due to relative motion of echoes, regardless of heading stabilisation. Head-up (Course-up, unstabilised)
keeps heading marker at 0º and the picture turns around it, which makes it unsuitable for narrow waters with
frequent course changes.

Direct comparison with visual. Relative bearing provides quick indication of bearing of target relative to ship’s
head Must check course for True bearings. Echoes ‘Blur’ (smear) when altering course or yawing. Not
possible to detect others relative motion when own headings changing Course-up stabilised has the picture
stabilised and heading marker mostly pointing upwards. When yawing, the picture remains still, but the
heading marker moves. System is reset bringing the course-up after change of course.

Direct comparison with visual mostly, with provision of obtaining true bearings. No blur or smear due to
change of heading The heading marker rotates when yawing or changing course, causing orientation
problems for some users North-up stabilised keeps the picture still and the heading marker shifts due to
change of course or yawing.

Direct comparison with chart. No smear due to own ship’s head movement. Increased bearing accuracy.
Actual relative movement of echoes can be detected by bearings and ranges of afterglow as long as it
remains. No direct comparison with visual and some individuals may find problems with orientation

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TRUE MOTION

There is no effect on echoes when own ship alters course. Discontinuity may occur when centre spot reset as
it could operate at awkward time. It is a good practice to carefully plan picture shift, especially after the ship
has settled on a new leg of passage. Similarly picture shifts should be performed at appropriate window of
opportunity and not left to last moment when dealing with close quarter or risk of collision situations. True
motion allows distinction between moving, fixed and stationary targets. Targets closing on a steady bearing
are not immediately apparent. Errors in heading and speed input may cause false movement to appear. It is
difficult to determine adjustments to completely remove the effects of wind, current or tidal stream. Early
warning is available due to increased range-ahead capability and there is no centering error.

Sea-stabilised (North-up)

Indicates course of all contacts through the water. Set and drift obtained at a glance by observation affixed
contacts. True alterations of course and speed of echoes displayed immediately. Errors in compass and
speed input cause false movement to appear on display.

Ground-stabilised (North-up)

Separation of stationary and moving targets. Useful in pilotage waters as ground speed displayed for target
Will not indicate course and speed of ships through the water.

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INTERPRETATION OF VECTORS AND TRAILS

On true motion, 4 targets have been used to illustrate the difference in vectors and trails with sea and ground
stabilised modes, tidal stream 090ºT x 3 Kts.

0 – Own ship (000ºT x 6 Kts)

1 – Fixed isolated beacon
2 – Target ship (180ºT x 6 Kts)
3 – Target ship (245ºT x 9 Kts)
4 – Target ship (Stopped in the water)

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There is no change in relative vectors with sea or ground stabilised speed inputs. But the true vectors and
trails change when the input changes between sea and ground speed. The input speed causes a change in
the speed and heading output of the targets, which affects the aspect. To emphasise this pint, the true vectors
for own ship and target 3 are produced in Figure. As can be seen, the seastabilised mode displays the true
vector without any error, where as the ground stabilised mode has caused an error in the true vectors,
resulting in an incorrect aspect

Key notes:
 Relative vectors do not change with speed input – CPA information iscorrect (within limitations) and is
independent of input.
 Sea stabilised or water track mode provides correct aspect, whereas with ground stabilised or ground
track mode, aspect could be wrong. Correct aspect may be required for deciding on collision
avoidance manoeuvre.
 Sea stabilised mode does not indicate whether own ship is being set, whereas ground stabilised
mode gives a quick indication of how own ship is being set. This implies that sea stabilised mode
should be used for collision avoidance and ground stabilisation for navigation.
 In open sea, if one radar is used off-centre, other should be centred.

ARPA - Automatic Radar Plotting Aid

 Calculates and displays Target’s Bearing, Range, True Course and Speed, CPA, TCPA.
 ARPA is excellent at tracking all visible targets but ONLY if they are visible on about 50 -75%of
antenna rotations.
 It is no use suddenly producing a strong echo only to be missing the next time the antenna goes
around.
 if not carrying a good radar reflector, most yachts cannot be tracked on ARPA.
 As always ARPA will depend on reliable inputs.

ARPA operational warnings for any selected target

 Target which closes to a specified range

 Target which enters a specified guard zone
 Target predicted to close to a specified minimum range and time
 A tracked target is lost

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ARPA Display

 Present range to the target

 Present bearing of the target
 Predicted target range at the closest point of approach (CPA)
 Predicted time to CPA (TCPA)
 Calculated true course of target
 Calculated true speed of target

MAINTAINING ARPA DISPLAYS AND OBTAINING ARPA INFORMATION

After setting up the ARPA, the user will want to effectively maintain the ARPA display and obtain information
from the ARPA.
The following are among the important points to remember in this regard.

 In the manual acquisition mode, continue acquiring recently appeared targets. Cancel tracked targets
that are non-dangerous or well past and clear to free memory space for more targets to be acquired.
 In the auto-acquire mode, the user must check from time to time that auto-acquisition is functioning
correctly. He may also have to adjust the auto-acquire areas or the exclusion zones as circumstances
change.
 Carry out ARPA performance tests on switching on the equipment and occasionally thereafter as long
as the ARPA is in use. These tests include the self diagnostic test, the manual diagnostic test and
manual tests.
 Watch out for danger targets and select them for alphanumeric data display. There are four ways to
monitor a target and check if it is a danger target.

 The danger target alarm

 Extend relative vectors (to monitor CPA & TCPA)
 Extend true vectors (check if ends of targets' and own-ship vectors meet)
 Alphanumeric (which give data of a limited number of targets at a time)

For a danger target,

 true vectors to decide which is the give-way vessel

 use past positions if the target is the give-way vessel, to determine if and when it maneouvers
 use the trial maneouvers facility if the own-ship is the give-way vessel, to help take avoiding action
 Switch. from relative vectors to true vectors occasionally to understand targets' headings. If PADs
are in use, occasionally switch to the vector mode.

In case of the following operational warnings take steps as stated.

Lost Target Alarm: Identify the lost target and investigate the reason it was lost; this may include
possibilities like target swop and fading. Re-acquire the target if necessary.
Lost Fixed Point. Investigate the reason it was lost. Ground reference again, preferably on a better fixed
target.

Target Manoeuvre Alarm: Locate the target and monitor it to see if the manoeuvre affects own-ship.

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In case of ARPA malfunction ;If the malfunction alarm goes off or if the ARPA data is found to
be incorrect, the user should switch off the ARPA and only monitor the raw radar display. He can use the
reflection plotter or the floating EBL for determining if a target is a danger target. Manual plotting can be done
on the reflection plotter or on a plotting sheet.

ERRORS IN ARPA

ARPA ERRORS IN DISPLAYED DATA

Errors of the ARPA may be broadly grouped under two main headings.
 Errors in Displayed Data (Equipment Errors)
 Errors of Interpretation (Human Errors)

ERRORS IN DISPLAYED DATA

These are errors due to the equipment and may be divided into :
 Errors due to radar
 Errors due to inputs (gyro and log)
 Errors due to ARPA processing

ERRORS DUE TO RADAR

Target Glint or Scintillation

The ARPA selects the centre of the echo as the position of a tracked target. It is possible that the centre of
the echo shifts as the echo is sent back by different parts of the ship when the target rolls, pitches and yaws
or when she alters course. This shift is called target glint or scintillation and is interpreted by the ARPA as a
movement of the ship creating slight inaccuracies in ARPA data for that target.

Errors in bearing

Errors in bearing due to the radar result in target positions painted incorrectly on either side of its
correct relative track. This leads to errors in ARPA data, notably in CPA and true course of target.
Error in the target's true course is greatest when the target is on a reciprocal course and end-on or
nearly end-on.

Some of the causes of bearing errors due to radar are described below.

Backlash in gearing.

The antenna drives an azimuth transmitter that transmits the direction of the radar beam (antenna
direction) to the display unit. The transmission drive between the antenna and transmitter is by means
of gears. Normally there is continuous gear tooth contact.
Sometimes aerodynamic forces may cause breaks in this contact causing backlash between the
antenna and the azimuth transmitter giving rise to an error in bearing. Modern transmissions have
reduced this problem.

Own ship’s motion causes antenna tilt and rolling parallax.

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Own ship's motion tilts the axis of rotation of the radar antenna causing a bearing error. This error is
zero when the target is ahead, astern and abeam and is maximum when the target is 45° on the bow
and astern. For example, a target at a relative bearing of 45° and own ship's roll of 7.5° would have a
maximum bearing error of -0.25°.

Own ship's rolling also shifts the radar antenna transversely off the own ship's fore and aft line
causing a bearing error due to parallax. This error varies directly as the height of
the antenna and the angle of roll and inversely as the range of the target.

Asymmetrical antenna beam

The ARPA normally takes the bearing of the target as that of the centre of the echo. In case the
antenna beam is asymmetrical about the line perpendicular to the antenna, the apparent position of
the target may shift depending on the echo strength, creating errors in bearing.

Azimuth Quantization Error

The bearing data of the target (antenna direction signal from the azimuth transmitter) must be
converted from analogue to digital form before it is input to the ARPA computer. This process of
conversion, called quantization, may introduce a small error called azimuth quantization error.

Errors in Range

Errors in range due to radar cause the target's relative track to be incorrect creating errors in
displayed data, notably in TCPA.

ERRORS IN RANGE MAY BE DUE TO THE FOLLOWING CAUSES.

Own ship’s motion

When the own ship rolls, the antenna is shifted transversely away from the fore and aft line. This
moves the antenna towards or away from the target resulting in a displayed range that is slightly in
excess of or less than the correct range. Pitch error is much less significant.

Range Quantization Error

The quantization of the target's range data from an analogue to a digital signal may give rise to a
small range quantization error.

ERRORS DUE TO INPUTS OF COURSE AND SPEED

Errors due to wrong inputs of course and/or speed affects all targets displayed true course and speed
(true vectors) but will not affect their displayed relative track (relative vectors).
The only exception to this is if the ARPA smoothes and stores true tracks (and there is a fluctuating
input; in most instances due to the log. In this case, the relative vectors will be in error till the input
stabilizes for a full smoothing period. As long as the input error is fixed and not fluctuating, the relative
vectors are still correct.

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It is important to note that sensor input alarms only operate on failure of input. They do not warn
against inaccurate input.

Errors due to the gyro include the following.

 Fixed gyro error.

 Random gyro errors due to the ship's roll, pitch and yaw.
 Misalignment between the master gyro and the input to the ARPA.

Errors due to the log include the following.

 Calibrated fixed log error

 Misalignment between the log and the input to the ARPA
 Fluctuations in log input due to various causes, e.g. bad weather

Errors due to a wrong manual speed input.

The speed input to the ARPA should be the correct ship's speed through the water. This is so as to
combine it with the gyro input, i.e., the course through the water. If the observer feeds in any other speed it
will create errors.

Errors due to ARPA Processing

These are errors due to the ARPA computer.

Target swop: Target swop occurs on a weak acquired target moving close to a large target when the
acquired targets vectors shift over the conspicuous target, indicating an error of displayed data.

Lost target: Changing over from a longer radar range scale to a shorter one reduces the radar pulse
length. This may result in a weak echo being filtered out completely. The ARPA will then be unable to track
the target and will activate the lost target alarm.

Own ship's maneouvers

In general, the relative and true data provided by the ARPA is correct when the own ship and the target ship
maintain their course and speed for the full smoothing period. A maneouvers by the own ship produces
temporarily unreliable ARPA data during and shortly after the maneouvers.

Own ship's maneouvers will alter the relative tracks of all targets. Though the smoothing period reduces, the
smoothing filter will combine the original track and the new track of each target. This results in a mean track
that will represent neither the old track nor the new track but will lie somewhere in between. After the own ship
has steadied on the new course or speed, a full smoothing period has to elapse before the relative vector
represents the correct data.

All targets' true data (true vectors) will also be similarly affected due to the varying input of own ship's course
and/or speed. In case of a tracker storing true data, the target's true track is more reliable as it is
independent of the own ship's course and speed.

Also note that, during a maneouvers, the own ship's movement may not be exactly the same as that fed in by
the gyro and log.

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Target's manoeuvre

A target's maneouvers leads to unreliable data for that target only. This is in contrast to a maneouvers by the
own ship where all targets' data are affected.
After the target's maneouvers is completed, ARPA data for this target is accurate only after a full smoothing
period has passed.

Summary :

Errors of ARPA :

Errors of ARPA are divided into two categories

 Errors in displayed data

 Errors of interpretation (Human Error)

Error in displayed data is divided into three types

 Due to radar
 Due to input
 Due to ARPA processing

Due to radar

 Glint or scintillation

Error in bearing

 Backlash
 Antenna tilt / Rolling
 Asymmetrical antenna beam
 Azimuth quantization

Error in range :

 Own ship’s motion

 Range quantization

Due to inputs of course and speed

Due to ARPA processing

 Target swap
 Lost Target
 Own Ship’s Manoeuvre
 Target Manoeuvre

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Errors in interpretation

 Failure to detect or acquire a target

 Incorrect use of vectors
 Confusion - trial mode or actual
 Error in use of past position
 Error in use of trials
 Re-acquired lost target
 Over-reliance on ARPA data
 Over-reliance Auto-acquisition
 False reliance on sensor input alarm.

SETTING UP THE ARPA

There is no standard ARPA model. Modern ARPAs far exceed the minimum IMO Performance Standards.
The sequence of setting up of ARPA varies with manufacturer and hence the ARPA manual must be
understood thoroughly if the full potential of the equipment is to be utilized.

Described below is a general sequence of setting up the ARPA.

Step 1: Set up the basic Radar

 The radar equipment that supplies the basic input data to the ARPA equipment must be set
up and tuned properly.
If the radar is not set up correctly it may not pick up weak target echoes. ARPA cannot
acquire and track a target if it does not show up as a radar echo. The ARPA user may be
unaware of this and placing undue reliance on the set will lead to potentially dangerous
situation.

Step 2. Select an appropriate

 Display Presentation

 b) Range Scale

a) Display presentation includes mode and orientation. This is dependent on the user’s preference.

 A North-up, true motion presentation will perhaps be best when navigating in poor visibility, when
both navigational obstructions and traffic have to be considered. In general, true motion is more
suitable for use with lower range scales and in congested coastal waters rather than in open sea.
 A Course-up, relative motion presentation is ideal for comparing the radar picture with the view
through the bridge windows; for example, when encountering traffic in open sea conditions or
when navigating through a buoyed channel.

In most other conditions, a North-up, relative motion presentation is considered to be the best.

b) The 12-mile range scale is recommended for normal as it gives provides ample area under observation
allowing the effective use of ARPA in assisting in navigation. Use shorter range scales when monitoring a
close-quarters situation, when negotiating narrow channels or for position fixing. Switch back to a longer

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range scale as soon as the situation permits. Range scales longer than the 12-mile must be used
occasionally for long range scanning to obtain early warning of the risk of collision.

Step 3: Check Inputs

Ensure that the gyro compass and log are functioning correctly and rectify any errors. Check that their inputs
to the ARPA tally with the master equipment.

The speed input to the ARPA should be the ship's speed through the water. This is to match the gyro input
which provides the ship's course through the water
.
All logs provide the ship's speed through the water except the Doppler log in the ground-lock mode (when it
provides the ship's speed over ground). Therefore, the Doppler log should be in the water-lock mode when
used to provide speed input to the ARPA. For manual speed input, enter the ship's present speed through the
water.

Step 4: Set up the ARPA

 Select the acquisition mode - either manual or automatic.

 In the manual mode, manually acquire all targets using the joystick and cursor. In case of the
automatic mode, set up the auto-acquire areas or exclusion zones depending on the ARPA set.
 Set the guard rings - fixed and/or variable at the desired distance off.

 Set the minimum safe CPA and TCPA limits. This also sets the PAD miss-distance if this facility is
available.
 .Select the vector mode (true or relative) or PADs if available.
 Set vector length in minutes. A default vector length may automatically appear on switching on.
Stars or similar symbols instead of vectors for all tracked targets indicate vector length is set to
zero.
 Ground-stabilize the picture if required.
 Switch-on past positions if necessary.
 Carry out operational tests before using ARPA data.

NOTES ON THE ABOVE ARPA SET-UP POINTS

 Auto acquisition - In case the vessel is in open waters, acquisition may be set for entire radar
screen. However, in coastal areas or in areas of heavy traffic or in bad weather, the user will limit
auto acquisition in sectors and also set exclusion zones.
 Cautions : The radar observer, should never neglect to monitor the raw radar display. It is
dangerous to rely completely on ARPA auto-acquisition facility as a lookout aid.
 Minimum safe CPA & TCPA : There are no fixed guidelines for setting up of minimum safe CPA
and TCPA limits. The observer, in consultation with the Master, decides this considering the
handling characteristic of the vessel, her response to the helm, and the prevailing traffic
conditions. The Danger Target Alarm sounds only when both the minimum safe CPA and TCPA
settings are violated by the target data. The larger the setting of CPA, the safer is the passing
distance. The longer the TCPA setting, the earlier will be the alarm activation. In open sea
conditions, a setting of CPA 3.0 NM and TCPA 30 minutes may be appropriate. In congested
areas, both CPA & TCPA will need to be earlier.

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 CPA cut-off limit: A target 8 miles off, the CPA calculated by the ARPA can he in error by up to 0.7
NM. While most sets have better accuracy than this, it is prudent to always exceed this amount
by a fair margin when setting the CPA limit. For example, set CPA at not less than 1.0 NM.
 TCPA cut-off limit: The Accuracy permits a maximum error in TCPA of 1 minute for a target 8 NM
off having a TCPA of 24 minutes. As this is not a considerable amount, one needs to consider the
time required to take an avoiding action. This also depends on the manoeuvring characteristics
of own ship. A 10 minute TCPA cut-off limit may be appropriate.
 The above cut-off limits further be reduced only in exceptional circumstances like narrow channels
and very congested waters.

AIS – Automatic Identification System

 AIS is a system for ships to communicate their positions as part of the global maritime safety
system (GMDSS).
 Ships over 300 tons carry an AIS system which broadcasts information about the ship
 AIS uses bursts of high speed data on two VHF channels in the marine band. 161.975 (Ch 87) and
162.025 (Ch 88) MHz.
 Ships broadcast their identity, type, MMSI number, position, course, speed and destination so that
other ships can take account of their movements.
 Other data is draught, length, cargo, no of passengers…
 Do not rely on this data for collision avoidance!
 Using an AIS receiver and a display, you see a radar-like real time chart of all the large ships
manoeuvring in your area.
 Required for VTS systems in ports

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CHAPTER 2

PERFORM RADAR PLOTTING

2.1 FACTORS AFFECTING RADAR PLOTTING ARE IDENTIFIED CORRECTLY

 While plotting on a chart please ensure that the scale remains constant.
 The Interval used for taking the observations is crucial to ensure that the plot can be developed
into a readily understandable and worked triangle.
 The Interval is again dependent upon the range scale in use and the speed of the two ships and
also on the approach speed between the ships.
 Use the Interval in such a manner so that the time may be converted easily into one place of
decimal. (6m = .1 hr.)(speed. 13.5 knots Interval 6m distance travelled 1.35 NM)
 North up plotting is generally considered more suitable since it compares well with the chart

2.2 CARRY OUT RADAR PLOTTING

Radar plotting is generally used to report on the radar contacts. Plotting can be carried out manually on a
plotting sheet, the reflection plotter or electronically. Regardless of the medium used, good results are
produced through a combination of the correct application of basic methods and skills of the operator. The
navigators should practice plotting skills in clear weather, when monitoring could be carried out by other
means, e.g. visual, and results can be checked against reality or radar simulations, e.g. trial maneouvers.
There are a few basics that the navigator needs to follow. Plotting tools (equipment) must be handy at all
times and ready for immediate use. Even basic things like keeping the pencils or china graph crayons
sharpened, are essential. The clocks should be kept synchronised, compared and checked. Adjustments
should be avoided to keep confusion at bay about the time in use.

The navigator should select equal time intervals between observations. Intervals like 3, 6, 10, 12, or 15
minutes are convenient fractions of an hour and lend to sensible arithmetic manipulation. The plotting interval
selected should be appropriate to the range scale in use, speed of own vessel and approach rates of the
target vessels. The targets should be marked on the plotter with an accurate cross or a fine point, instead of a
large blob. Electronic markers should be used where available. The targets should be given designators at
this stage. This approach is very helpful when observing a number of targets simultaneously. The actual
ranges and bearing should be picked up from these marks for plotting purposes. This avoids the errors that
may be introduced due to inaccurate timing or changing the sequence of observing/plotting the targets.

PROCEDURE AND TERMINOLOGY

A following basic plot demonstrates the vectors and the terminology used for relative plotting, along with some
aspects of the procedure.

Example 2.1.1

A vessel heading 320º T at 21.5 knots, observes another vessel on the radar.
Following observations were made:
0900 020ºT 10.0
0906 025ºT 8.1
0912 032º.5 T 6.4

Compile a radar report for 0912.

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Solution and Comments

Plot the heading line of the observing ship and mark it with course and speed,320º T x 21.5 Kts. Plot the three
bearings and ranges. The first one should be labeled ‘O’ and the final as ‘A’. Make a note of the times of each
observation next to the respective mark. Where observations are made on head-up display, the relative
bearings may have to be converted to true bearings.
Draw a line of best fit through these points. This is the ‘OA’ line – line of relative approach – and should be
run past the centre of the plotting sheet or display.
Mark an arrow in direction ‘O’ to ‘A’ and encircle it. In actual practice during real time plotting, before
proceeding further, the points should be seen to fall closely on this line and that they are not scattered unduly.
See if the points are similar distance apart. If the distances are uneven for equal time interval or the points are
asymmetric, it could indicate that the observed target is in the process of changing course and/or speed, or
that there are errors with the observations.
The ‘OA’ line provides information on risk of collision. If this line passes through the middle of the sheet, the
observed vessel is on a collision course. If it does not pass through the middle, as in this example, the
distance that it passes from the middle should be determined. This is done by drawing a line perpendicular to
the ‘OA’ line which passes through the middle of the plot, ‘B’. The perpendicular meets the ‘OA’ line at point
‘X’, which is the CPA. Distance ‘BX’ is
the distance off at CPA, which is 3´.4. An arc also indicates the CPA distance

The direction of line ‘BX’ indicates the bearing of CPA.

Time of relative approach can also be measured along the ‘OA’ line. Distances
‘OA’ and ‘AX’ should be measured, and are 4´.0 and 5´.4 respectively.

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‘OA’ is the approach distance covered during the plotting interval.

Time to CPA = (AX ÷ OA) x Plotting interval
(5.4 ÷ 4.0) x 12 = 16.2 or 16 minutes
Time of CPA = 0912 + 0016 = 0928

Produce ‘WO’, usually referred to as ‘way of own’, in the direction of the observing ship’s course, to join at ‘O’.
Mark a single arrow on this line indirection ‘W’ to ‘O’. It is own vessels motion line and equals:

WO = (Speed of observing ship ÷ 60 minutes) x plotting interval minutes

WO = (21.5 ÷ 60) x 12 = 4´.3.

During actual plotting, ‘WO’ could be produced and plotted after the first plot has been marked in order to
complete the vector triangle with minimum delay.

Similarly, the plot should be labeled at an early stage, so that rest of the bridge team can also understand the
plot and interpret it. After plotting ‘WO’, join ‘W’ to ‘A’ to produce line ‘WA’ which is the true track of the
observed ship, usually referred to as ‘way of another’. Mark a single arrow on this line in direction ‘W’ to ‘A’.
The direction of ‘WA’ indicates the course or track of the

observed vessel – 255º T – and its length is indicative of the speed.

Speed of observed ship = (WA ÷ Plotting interval in minutes) x 60 minutes.
Speed = (2´.8 ÷ 12) x 60 = 14 Kts

Final stage is the aspect. It is relative bearing of the observing vessel from the target vessel, or angle on the
bow of the target vessel. It is expressed from 0º to180º Red or Green depending on whether the observing
vessel is on the Port or Starboard side of the target vessel. It is worked out as the difference between the
Target’s true course and the reciprocal of the last observed bearing.
Reciprocal of last observed bearing 032º.5 T is 212º.5 T
Aspect = 255º T ~ 212º.5 T = Red 42º.5 (always obtain shorter angle)
It can be worked out from the azimuth ring on the plotting sheet when course and bearings are marked while
measurement.

REPORT
Most navigators believe the report is based upon six items: Course, Speed, CPA, TCPA, BCPA and Aspect.
These are generally the outcomes of the plot, but do not necessarily provide all pertinent information about
the target. For a full report or analysis of the situation, the following should be reported:
 Time of the report
 Target identifier or designator (where tracking a number of targets)
 Target’s last observed true bearing
 Bearing Steady, Closing (drawing forward) or Opening (drawing aft)
 Target’s last observed range
 Range Steady, Decreasing or Increasing
 Distance of target’s CPA
 Bearing of target at CPA (true or relative)
 ‘Time to’ and ‘Time of’ CPA
 Calculated true track/course of the target
 Calculated speed of the target
 Target’s aspect
 Where applicable general comments like overtaking or crossing

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For Example 2.1.1, the full report may read: 0912; bearing 032º.5T; opening(drawing aft); range 6´.4,
decreasing; CPA 3´.4, bearing 090ºT in 16 minutes at0928; course/track 255ºT; speed 14 Kts; aspect Red
42º.5. Information may be presented in tabular format, especially when plotting multiple targets.

CURRENT OR TIDAL STREAM / OTHER RELATIONS BETWEEN ‘O’,‘A’ AND ‘W’

Plot 1: Observing vessel is making way and the plot includes only the observations made during the plotting
interval. There is no tidal stream. Note that for “A”, ‘O’ and ‘A’ are at the same point.

Plot 2: There is no tidal stream and the observing vessel is making way. ‘WO’ is applied to both the targets
“A” and “B”. For “A”, the ‘WO’ and ‘WA’ are in line, indicating that the target is moving on the same course and
speed as the observing vessel. In case of “B”, ‘W’ and ‘A’ fall on the same point, indicating a zero ‘WA’, which
means that the target is stationary.

Plot 3: There is no tidal stream and the observing vessel is not making way; hence ‘WO’ is zero. “A” is seen
to be moving and “B” is stationary. For “B”, ‘O’ and ‘A’ remain at the same point. Since ‘WO’ is zero, the
relative approach of“A” is its true track as well. ‘OA’ = ‘WA’.

Plot 4: The observing vessel is making way and a tidal stream is setting West. Plot of “A” is normal, where
as the distance between observing vessel and “B” is gradually increasing. “B” is known to be stationary. A
fixed stationary object cannot be moving ‘WA’, hence the vector ‘AW’ is the tidal stream, indicated by three
arrow heads. The direction ‘AW’ is the set indicated as ºT. The length of ‘AW’ is the drift experienced by the
observing vessel during the plotting interval and is measured in nautical miles. It is used to work out the rate
of tidal stream. Rate of Tidal Stream = (Drift ÷ Plotting interval in minutes) x 60 minutes

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ALTERATION BY OBSERVED VESSEL

The navigator needs to spot change in the direction and length of W

Example 2.1.2

A vessel steering 350ºT at 15 knots, observes two targets on radar as follows:

0900 A - 006ºT x 10´.4 B - 305ºT x 10´.6
0910 A - 017ºT x 8´.5 B - 303ºT x 8´.5
0920 A - 032.5ºT x 7´.1 B - 301º x 6´.4
If “A” is known to be a light vessel, compile a radar report for 0920.

Observation of “B” continued as follows:

0930 292.5ºT x 5´.0
0940 259ºT x 3´.3
0950 211ºT x 3´.8
What action has been taken by “B” between 0920 and 0930?

Solution and Comments

Standard plotting procedure as described earlier should be followed. For “A”,‘AW’ indicates the tidal stream,
as it is a stationary object. For observation of “B” from 0930 onwards, the labels have been changed asO1,
W1 and A1. W1A1 should be examined for any change. The change indirection is indicator of change in
course and the direction W1A1 is the new course. Change in the length indicates change of speed. Zero
length of W1A1would have meant that the target had stopped.

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For “B” at 0950, all details have been added, in addition to new course/speed. Note the ‘past’ TCPA and
change of aspect to red. In the plot, above ground track of the observing vessel has been marked. It is
reciprocal of the relative plot of the fixed stationary object, i.e. 328ºT at a
speed of 15.4 Kts (from length of OA). It can be used to obtain the ground track of the target “B” and is
illustrated in

ALTERATION BY OBSERVING VESSEL

In this case, the change of course is indicated by new direction of ‘WO’ and change of speed is indicated by
change of length of ‘WO’. Where the observing vessel stops, ‘WO’ will be zero. In case of stopping, what
would be the resultant relative approach of the target? In most problems, the alteration may be
instantaneously effective (Example 2.1.3). But in real life and in some problems, the alteration will have to
allow for steadying on the new course or speed. This will involve application of head reach of the observing
vessel during the manoeuvre.

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HEAD REACH

In reality, when a vessel commences a manoeuvre, the intended course or speed is not effective at once.
Usually, there is a time interval between commencement of manoeuvre and its completion. During this period,
the direction and/or length of the relative approach is also changing. The distance travelled by a vessel in the
direction of the initial motion during the manoeuvre is identified as ‘Head Reach’. The exact value can be
determined from maneuvering characteristics of a vessel, its speed, loading condition, depth of water, sea
state and the helm angle used.

It may not be possible to include all the above information in an exam style problem. Usually head reach
distance and the time during the manoeuvre would be included. For plotting purposes, the effective time of
manoeuvre is taken as the half way of the time into manoeuvre to plot the new approach line, as the curved
path may be plotted conveniently (Example 2.1.5).
Another option is to plot the new approach from a position of the target vessel when the observing vessel has
steadied on the new course/speed. In such cases a bearing and distance of the target would be provided
(Example 2.1.4).

Example 2.1.3

Using the information and initial observations in Example 2.1.2, and assuming any alterations are
instantaneously effective, find a single alteration of course to be made by the observing vessel at 0930, in
order to pass the vessel “B” at a distance of 3 miles. What effect will this alteration have on target “A”? Find
the earliest time at which the observing vessel may resume its original course. Solution and Comments Draw
heading line of the observing vessel from the centre ‘B’ and label it 350ºT@ 15 Kts. Plot the bearings and
ranges of targets “A” and “B”. Label the points and mark them with times. Add ‘WO’ line to complete the
‘OAW’ triangles.
Extend ‘OA’ line for both. Mark the vectors with appropriate arrows.

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The initial CPA of “B” was 1 mile on the port side. In order to pass it at 3 miles, course should be altered to
starboard. If it was restricted visibility, avoid altering course to port for a vessel forward of the beam (Rule 19
d). Even in clear visibility, when taking action, a power driven vessel should avoid altering course to port for a
power driven vessel on its own port side (Rule 17 d).Using a radius of 3 miles and centered on the sheet,
describe an arc towards the port side of the observing vessel. Avoid drawing a full circle for making a decision
against a single target, as mistake of altering the wrong way can be made. Circle should be used when
decision has to be made considering a number of targets.

Since course alteration is required for 0930, it is important to determine these points for both the targets.
Measure the length of the ‘OA’ vector for both separately; this is the approach for 20 minutes. Half of this
distance should be used to obtain the 0930 position for the targets (If in another problem, the time interval is
not exactly half, use the appropriate fraction). Label it as A1.For target “B” (as 3 miles is required from it),
draw a line A1X1 from A1 as a tangent to the arc drawn earlier. This is the required relative approach to pass
“B” at 3 miles. With centre W and a radius of WO, describe an arc to starboard of WO. Draw a line parallel to
A1X1 from A backwards to intersect the arc from W as the centre. Label the intersection point as O1. Join W
to O1. OWO1 is the alteration of course required to pass “B” at 3 miles, i.e. 25º. The new course is350ºT +
25º = 015ºT.

For effect on target “A”, from point W, draw the new WO1 in direction 015ºT at15 kts. Join O1 to A and obtain
the new relative approach line for target “A”. Draw a line parallel to O1A from point A1 and run it past the
CPA, X1.For time of course resumption, draw a line tangential (and parallel to the original OA) to the 3 mile
arc to intersect at Y the new line of relative approach A1X1.The point of intersection, Y, of these tow lines

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marks the earliest time that the observing vessel may resume its original course. The time can be determined:
Time interval = (A1Y ÷ O1A) x Plotting interval= (4´ ÷ 2´.8) x 20 = 28.57 minutes = 29 minutes
Time of resumption = 1930 + 29 = 1959

Example 2.1.4

A vessel steering 300ºT at 18 Kts, observes a vessel on radar as follows:

0800 340ºT 9´
0810 340ºT 7´
0820 340ºT 5´

Compile a report for 0820. If the observing vessel alters course to 350ºT, find the CPA information about the
target if it was bearing 330ºT x 3´.5 at 0830when the observing vessel is steady on its new course?

If in this situation, a decision was to be taken to reduce the speed instead, what speed should the observing
vessel reduce to, in order to get the same result?

Solution and Comments

Report: 0820; Brg 340ºT, steady; Range 5´, decreasing; CPA 0; BCPA 340ºT:TCPA in 25 minutes at 0845;
Course 259ºT, Speed 11.7 Kts, Aspect Red 99º.

After completing the basic plot and compiling a report, with W as centre and WO as radius, describe an arc to
starboard of O. From W draw a line in the direction of 350ºT to reach the arc drawn. Call this intersection
point O1. Join O1 to A. This is the new relative approach of the target after observing vessel has altered
course. O1‘c’ is so labeled to indicate its relation to course change. Plot the bearing and range for 0830. From
this point, draw a line parallel to O1Aand run it past the CPA. Obtain CPA information based on this new
approach.CPA 2´.8; BCPA 292º.5T; TCPA in 9 minutes at 0839.For possible speed reduction, the point where
the new O1A line intersects WO has been labeled O1‘s’, to indicate its relation to speed change. Measure the
length W to O1‘s’. This is the distance to be travelled in 20 minutes if speed is reduced. This distance can be
converted into speed = 9.9 Kts.

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CHAPTER 3

USE ARPA AND NAVIGATION INFORMATION TO CONTROL

SAFE NAVIGATION AND COLLISION AVODANCE
3.1 APPLY COLREGS IN OPEN WATERS IN RESTRICTED VISIBILITY

RULE-19 CONDUCT OF VESSELS IN RESTRICTED VISIBILITY

(A) THIS RULE APPLIES TO VESSELS NOT IN SIGHT OF ONE ANOTHER WHEN
NAVIGATING IN OR NEAR AN AREA OF RESTRICTED VISIBILITY .
In or near restricted visibility: There is no specific range within which an area would be considered as an area
of restricted visibility for the conditions mentioned in Rule-3(l). For instance, if visibility is restricted by haze to
ten miles (in clear weather, it may be 12 miles), you would not be in an area of restricted visibility. On the
other hand for instance, in open water, you should consider that you’re in or near an area of restricted visibility
if you cannot see five miles in all directions. In confined waters, this distance may be less. Usually, a Master’s
standing orders and/or company policy state the range of visibility at which the presence of Master is required
at bridge.
Your vessel may be in an area of good visibility but may also be close to a fogbank concealing one or more
vessels. Even though you are in the clear visibility, you must follow Rule 19 and sound the signal required by
Rule 35.
If you’re in an area of good visibility and a vessel emerges from the fogbank and comes in sight of one
another, you must follow Rules 11 through 18 and sound any signals required by Rule 34. It is therefore
possible for you to be following at the same time rules for good visibility and the rules for restricted visibility.
You must assess the situation before you determine which rules shall apply.

(B) EVERY VESSEL SHALL PROCEED AT A SAFE SPEED ADAPTED TO THE

PREVAILING CIRCUMSTANCES AND CONDITIONS OF RESTRICTED VISIBILITY. A
POWER-DRIVEN VESSEL SHALL HAVE HER ENGINES READY FOR IMMEDIATE
MANEUVER.

Speed in Restricted Visibility: The decision to reduce speed in an area of restricted visibility depends on
various conditions, such as the range of visibility, vessel’s stopping capability, traffic density, open or
congested waters, etc. If the area of restricted visibility is not very large and there is open water with less
traffics, it might be rather prudent to speed up and clear that area quicker.
Readiness of Engines: It’s mandatory for a power-driven vessel to have her M/E ready for immediate
maneuver in restricted visibility. The bridge should give sufficient notice to E/R to prepare the engines and the
E/R should be manned. Master must remember that if collision takes place due to the fact that speed was not
reduced due to commercial reasons, he would be guilty of an offence for not complying with this obligation.
Ship operators MUST not compel the Master to violate this requirement.

(C) EVERY VESSEL SHALL HAVE DUE REGARD TO THE PREVAILING

CIRCUMSTANCES AND CONDITIONS OF RESTRICTED VISIBILITY WHEN
COMPLYING WITH THE RULES OF SECTION I OF THIS PART.

This paragraph emphasizes to have due regards to the conditions of restricted visibility while doing a closer
scrutiny of Rules 4 to 10 same time. Again the key words come into picture – maintain safe speed, use

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radars, determine RoC, keep look out, take appropriate actions, etc. It’s imperative to strictly comply with the
check list of restricted visibility mentioned in Bridge Procedures Guide and/or in Company Manuals.

(D) A VESSEL WHICH DETECTS BY RADAR ALONE THE PRESENCE OF ANOTHER

VESSEL SHALL DETERMINE IF A CLOSE-QUARTERS SITUATION IS DEVELOPING
AND/OR RISK OF COLLISION EXISTS. IF SO, SHE SHALL TAKE AVOIDING ACTION
IN AMPLE TIME, PROVIDED THAT WHEN SUCH ACTION CONSISTS OF AN
ALTERATION OF COURSE, SO FAR AS POSSIBLE THE FOLLOWING SHALL BE
AVOIDED:

Detection by radar alone: It means the detection of other targets is done not by sight (visual) and hearing (fog
signal).
Determining risk of collision: Rule-7(b) co-relates this paragraph. A detailed discussion has been done about
it in Rule-7.
Development of a close-quarters situation: Rules 8(c), 19(d) and 19(e) refer to a close-quarters situation. In
restricted visibility, the range at which a close-quarters situation between two vessels could be considered
depends upon various conditions, such as, open or congested water, present speed of the vessels, etc. There
is no specific range for it. Usually a 3-mile range could be taken for a close-quarters situation. Sometimes, we
consider the audibility range of sound signaling equipment to be the determining factor of the range of a
close-quarters situation. But it’ll always depend upon the prudent judgments of the Master or OOWs.
Ample time: This is explained in Rule-8(a). If RoC exists, a vessel should take avoiding action in ample time
to avid the collision.
Stand-on vessels: In restricted visibility, there is no stand-on vessel. There is no requirement of maintaining
course and speed by one vessel.
Alteration of speed: An alteration of speed or change of both course and speed can be made instead of an
alteration of course alone.

(i) AN ALTERATION OF COURSE TO PORT FOR A VESSEL FORWARD OF THE

BEAM, OTHER THAN FOR A VESSEL BEING OVERTAKEN;

Alteration to port: By the words ‘so far as possible’ this paragraph leaves an option for a vessel to make an
alteration to port if a close-quarters situation is developing and/or risk of collision exists due to some special
circumstances, such as, lack of sea room to starboard or to the presence of other vessels, etc. If an alteration
to port is required, it must be done early and a large alteration is always encouraged when avoiding a close-
quarters situation with a vessel approaching from ahead or fine on the bow. A vessel may alter in either
direction when she approaches from astern of a vessel being overtaken (i.e. the overtaken vessel is forward
of the beam of overtaking vessel).

(ii) AN ALTERATION OF COURSE TOWARDS A VESSEL ABEAM OR ABAFT THE

BEAM.

Abeam or abaft the beam: Abeam is a perpendicular line to the centerline of the vessel. Abaft the beam
means behind abeam. For easy reference and convenience, an OOW usually assumes the bridge wings as
the points of abeam - port beam and starboard beam. A vessel a beam (at beam) doesn’t necessarily mean
that she is approaching towards the bridge wing of own vessel.

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(E) EXCEPT WHERE IT HAS BEEN DETERMINED THAT A RISK OF COLLISION DOES
NOT EXIST, EVERY VESSEL WHICH HEARS APPARENTLY FORWARD OF HER
BEAM THE FOG SIGNAL OF ANOTHER VESSEL, OR WHICH CANNOT AVOID A
CLOSE-QUARTERS SITUATION WITH ANOTHER VESSEL FORWARD OF HER BEAM,
SHALL REDUCE HER SPEED TO THE MINIMUM AT WHICH SHE CAN BE KEPT ON
HER COURSE. SHE SHALL IF NECESSARY TAKE ALL HER WAY OFF AND IN ANY
EVENT NAVIGATE WITH EXTREME CAUTION UNTIL DANGER OF COLLISION IS
OVER.

If risk of collision does not exist: If it has been determined that risk of collision does not exist a vessel is not
required to reduce her speed to the minimum at which she can be kept on her course. Example – two vessels
proceeding in correct sides of a narrow channel in opposite directions and one vessel may hear the fog signal
of another vessel but this doesn’t mean that a RoC exists. RoC not determined & a vessel hears a fog signal
ahead: It easier to hear the other vessel's signals when a vessel is stopped. Once a fog signal of another
vessel is heard forward of the beam, you can’t conclusively say what the other vessel is doing. She may be
making way, stopped, or anchored. Determine whether RoC exists using all available means as per Rule-7.
Once the fog signal is heard forward the beam, a vessel must reduce her speed to the point of bare
steerageway. Do not change course until you know the other vessel's position, course, and speed. If you
cannot quickly clarify the situation, do not continue blindly into the great unknown. Stop your vessel until you
establish the location and intentions of the vessel(s) ahead and if a RoC exists. A vessel which hears two
pronged blasts from another vessel must not assume that the other vessel will remain stopped.

Direction of Fog Signal: The direction of sound signals may be misleading in fog. The exact bearing of a
sound signal can’t be determined always. That’s why, even when you hear a fog signal abeam or slightly
abaft the beam, you should reduce speed to assess the situation.
A vessel can’t avoid a close-quarters situation: If a close-quarters situation cannot be avoided, with a vessel
forward of her beam, the speed must be reduced to the minimum at which a vessel can be kept on her course
and she must do so in ample time without waiting for a close quarters situation to develop.

Taking all way off: A vessel which cannot avoid a close quarters situation with another vessel forward of her
beam might as well be expected to reverse her propulsion and take all her way off. When a vessel with a right
handed propeller falls astern, the bow cants to starboard due to transverse thrust and the vessel may come
off the original course significantly to cause confusion to the other vessel. One of the advantages of taking all
way off is that the impact of collision will be minimum if contact occurs (God forbids!) forward of the collision
bulkhead.
Navigate with extreme caution: There is no better one than the caution that ensures avoidance of a collision.
Some examples of extreme cautions:-
 Have full regards to the circumstances and conditions of restricted visibility
 Ensure good and effective look out. Ensure that appropriate manning level is maintained on bridge
 Comply with the check list of Restricted Visibility as mentioned in OCIMF Bridge Procedures Guide
 Use all available means to determine a RoC
 Don’t take action basis scanty radar information
 Don’t start altering course soon after hearing a fog signal heard forward of the beam
 Proceed with safe speed. Reduce speed or even revere your propulsion if necessary

Not surprisingly, the courts have found that the phrase ‘close quarters situation’ is open to argument. Since
fog signals (for vessels over 200 meters) have to be audible for 2 miles, this has become the generally
accepted distance at which a close quarters situation might be said to begin. For smaller maneuverable

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vessels it could be considered rather less. If we keep to the fog signal analogy it would be half a mile for
vessels below 20 meters.

For larger vessels in the open sea is has been suggested that using a 12-mile range scale, targets should be
assessed while in the outer third of the screen and if a close quarters situation is developing, action should be
taken before they reach the inner third. Smaller vessels might do likewise on a lower range scale.

It should always be remembered that small timber or fiberglass vessels often do not return an echo until they
are quite close to the ‘searching’ radar, an area of the screen which may be obscured with sea clutter. A good
radar lookout includes frequent changes of range to determine whether this is happening. Small vessels
should deploy properly designed radar reflectors whenever possible.

On some large vessels, the conning position and radar scanner can be more than 200 meters from the bow.
This creates a long ‘shadow’ sector where small craft cannot be seen either visually or by radar.

There is no ‘stand-on’ or ‘give-way’ in Rule 19. That applies only when vessels are in sight of one another. In
restricted visibility, every vessel must take avoiding action—not only if there is a risk of collision but also if a
close quarter’s situation is developing. Close quarters situations can develop from astern as well as ahead.
 An alteration of course to port for a vessel forward of the beam, other than for a vessel being
overtaken;
 An alteration of course towards a vessel abeam or abaft the beam.
The words ‘so far as possible’ are included in case an alteration to port is necessary due to lack of sea room
or the presence of other vessels. Such action must be made as early as possible and as boldly as possible.
‘Abeam’ means at right angles anywhere along the ship’s length.

The words ‘so far as possible’ are included in case an alteration to port is necessary due to lack of sea room
or the presence of other vessels. Such action must be made as early as possible and as boldly as possible.
‘Abeam’ means at right angles anywhere along the ship’s length.

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There is no ‘stand-on’ or ‘give-way’ in Rule 19. That applies only when vessels are in sight of one another. In
restricted visibility, every vessel must take avoiding action—not only if there is a risk of collision but also if a
close quarters situation is developing. Close quarters situations can develop from astern as well as ahead.
(e) Except where it has been determined that a risk of collision does not exist, every vessel which hears
apparently forward of her beam the fog signal of another vessel, or which cannot avoid a close quarters
situation with another vessel forward of her beam, shall reduce her speed to the minimum at which she can
be kept on her course. She shall if necessary take all her way off and in any event navigate with extreme
caution until danger of collision is over.

The Rule phrases this in such a way as to emphasise that you have specifically determined by use of radar
that there is no risk of collision, and ensured that any fog signals from forward of the beam have been
positively identified and do not pose a threat – that they are, in fact, from the vessel which you think they are
from, remembering that the direction of sound in fog can be very deceptive.
It tells us exactly what to do if:

 We hear a fog signal apparently forward of the beam

OR
 We cannot avoid a close quarters situation with another vessel forward of the beam.
We must:
 Reduce speed to steerage way
 Take all way off if necessary, AND
 Navigate with extreme caution.
 Before altering course to avoid a collision, you need to know which way the other ship is heading
with respect to your own vessel. This is called her aspect and it cannot be determined from a fog
signal. It is also difficult to determine quickly from a radar target. A radar plot as shown could
represent a vessel with aspect Red 30º as sketched next to it.

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On the other hand, it could also represent the two situations below.

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If radar indicates an unavoidable close quarters situation with a vessel approaching from ahead or within
about 30° of the bow, a vessel would be expected to reverse engines and take all way off, while remaining
head on to the danger so as to present a smaller target.

3.2 PLAN AND CONTROL NAVIGATION IN CONFINED WATERS

Radar happens to be a very effective aid to navigation as it provides range and bearings of objects detected
within the range scale. Apart from plotting position, it can be used effectively for continuously monitoring the
vessel’s progress in coastal waters.

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PARALLEL INDEXING

As a vessel moves on its intended track, fixed objects in the vicinity appear to be moving in the reciprocal
direction of its motion (ground track). This technique provides the radar observer with real-time, instant
information on ship’s lateral position relative to the planned track. The information is essential in restricted
waters with lot of traffic congestion as frequent course changes that need to be made can only be made if
vessel is operating within its planned margins of safety. For these reasons it is particularly useful during
restricted visibility. Provided the passage plan has been prepared diligently, parallel indexing provides
confidence to the bridge team about continued progress of vessel in safe waters. At least two methods can be
used for PI.

“Cross Index Range” (CIR) Method – Straight Index Line This is based upon the lateral distance of the
planned track from a selected object. It can be employed at all times when using PI. Having identified all the
hazards, marked the limiting danger lines and tracks, a suitable charted object should be selected. A line
parallel to the planned track should be drawn on the inner edge of the selected object and not through it.
Maximum “margins of safety” (MOS) should be marked either side, or the side with off-lying dangers.
Perpendicular distance should be measured from track to this line. This distance is the CIR. Distances should
also be measured for the MOS.

In above Figure, CIR is 4´.0, MOS port 2´.0 and MOS starboard 3´.0 from track.MOS port is 2´.0 (4 – 2) and
MOS starboard is 7´.0 (3 + 4) from the Index line. The MOS port distance is treated as “not less than” (NLT)
distance from the danger and MOS starboard as “not more than” (NMT) distance from the index line.

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The three lines should be marked on the radar screen as index line and MOS lines either electronically or on
the plotter using VRM and cursor. Most modern radars have the capability of producing index lines directly
without the use of VRM. To proceed safely, the selected object should remain on the track index line, and
never outside the NLT and NMT lines. VRM can also be set to monitor. This method can also be used for
course alterations. The CIR for the present and the next track should be measured off a selected object. It is
preferable to use a single object in this case. The index lines, and if required the MOS lines, should be
marked.

For wheel over, measure the perpendicular distance between wheel over mark and the next track (025ºT)
index (2´.0). Mark this on the radar. When the echo of selected object reaches the wheel over index (point
“1”), planned helm should be applied. On completion of turn the vessel would be on the planned track, with
the echo on the next track index (point “2”).

Bearing and Range Method – Straight Index Lines]

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The scenario illustrated in above Figure has been used here. The “bearing andrange” from the way point –
and the wheel over mark – should be determined.

The range and bearing from way point should be marked on radar display in reverse. From this point (“2”), the
index lines for the 090ºT track and the reciprocal of 025ºT should be marked. Initially the echo of selected
object would be on the 090º index. As it reaches point “1”, planned helm should be applied and the echo
would steady up on the 025º index line once the ship has steadied on the new heading. Course corrections
may be required to maintain track.

Bearing and Range Method – Curved Index Lines

Turns within narrow or congested waters are critical and require good monitoring, which can also be achieved
through PI techniques. This can be performed in two ways. Where it is just an alteration between two tracks
(Below figure ), the curve can be plotted first on the chart using information from the maneuvering information
on turning circles of the ship. A suitable object on the inside of the curve should be selected and ranges and
bearings for different changes of heading from this object should be plotted. This information can then be
transferred to radar.

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Alternately, the ship may be navigating through a narrow channel with frequent course changes and
executing curves of differing curvature, using different helm. In such cases, the intended position of ship
within the channel should be marked, which depending upon the channel may take the form of a curve. On
this curve points at about 1 to 3 cables should be selected. Bearings and ranges of these points from a
convenient fixed object for indexing should be measured for transfer to radar. This object should preferably be
on or close to centre of curvature of the curve. A table can be prepared listing the range and bearing of the
selected object, along with the helm and engine orders planned to execute the manoeuvre.

Zero CIR – Narrow Channel Technique

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This method makes use of ground stabilised input and relative vectors, and issued in areas where channels
are well marked with beacons or buoys. A single line parallel to track of the ship is drawn or marked on the
radar through the point of origin to act as the intended ground track of the ship. Relative vectors or trails
should be selected to detect the cross track tendency. As long as the relative vectors or trails are parallel to
the index line, the ships ground track is in line with the intended track.

The distance of channel markings can be determined from the origin, indicating which way the ship is setting.
Additionally, VRM can be used to monitor distances from the channel markings. Actual heading may be
different to make adjustments. VRM can also be used with the CIR method to check safe distances if the
bridge team decided not to use the NLT or NMT lines.

USE OF NAV LINES

Most radar and ARPA units include added functions of Mapping and/or Nav-Lines. These functions can be
used for channel keeping or track keeping within margin of safety in congested waters. The maps or navlines
can be created electronically. The operator would select a fixed object to ground reference the ARPA. The
monitoring would be performed conveniently and the bridge team would be able to plan for the course
correction or course change accordingly.

The object selected for reference should preferably be an isolated fixed object, e.g., a very small island, a
beacon in the water, etc. Where a selected object carries a RACON, it is possible that the ARPA might track
the RACON signature of the reference target. In the event of this happening, the nav-lines could move off the
channel reference and the bridge team should choose another navigational aid for reference and redraw the
nav-lines. On some units it is possible to fix the position of nav-lines with respect to the ship. These lines can
then be used in traditional parallel indexing manner.

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PRECAUTIONS WITH PARALLEL INDEXING

Precautions must be observed after carefully preparing a plan to effectively use parallel indexing for
monitoring the ship’s progress. The radar should be set up properly, presenting a picture of good quality and
displaying the required echoes effectively. Control settings should allow optimum picture. Suppressing
controls like rain and sea control should be kept to required minimum and should be turned off when not
required. Time base must be accurately centered.
 Radar should be checked for range, bearing, heading marker and picture rotate accuracy.
 Compass error needs to be known; heading marker carefully aligned.
 Choice of navigational set up depends upon area of operation. Northup relative motion would be
preferable in coastal waters; whereas Northup true motion would be a choice in narrows.
 The selected object should produce good radar echo. Preferable choice would be steep sided, radar
conspicuous marks, e.g., headlands, isolated rocks, isolated beacons, navigational marks with
RACON.

 Objects should preferably be selected on both sides of ship’s track to minimise range plotting error,
mark identification error and radar linearity error. Low lying objects and coast line should not be used,
e.g., sand dunes, tidal low coast lines, etc. Objects should be correctly identified.
 The selected object should not be obscured from the radar scanner due to presence of other objects.
 Consideration should be given to radar blind and shadow sectors and for how long the selected
object is likely to remain within these sectors.
 Range scale is an important factor, in particular when it needs to be changed. On older conventional
radars with reflection plotters, any change of range scale during parallel indexing would cause major
workload for navigator. Most modern radars allow index lines to shift with change of range scale.
However, not all modern radars perform accordingly, as index lines do not shift. Navigators need to
know limitations and peculiarities of own radars. Check VRM and range rings.
 Too many index lines clutter the display. At any given time, not more than two sets should be on the
radar display – one currently in use and the other for use immediately after the present set.
 Parallel indexing does not relieve the navigator of the responsibility to plot positions at the
predetermined intervals.

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LANDFALL

Radar should be used with caution when using it for landfall. Under normal conditions, radar pulses travel in a
straight line. This implies that the radar can detect objects far beyond its horizon, provided that the object is at
a suitable elevation to be negotiated by the radar. The maximum range that radar can detect up to depends
upon the height of scanner and height of the object. The maximum range “R” can be determined by formula:

R = 2.23 (Zh + ZH) sea miles (where heights are in meters)

R = 1.23 (Zh + ZH) sea miles (where heights are in feet)

A ship fitted with radar scanner 35 m above sea level can detect a 450 m high peak at a range of 60.5 miles.
The formulae can be transposed to determine the height of the object “H” that can be detected at a given
range.
H = 0.201 (R – 2.23 Zh)2 (heights in meters)
H = 0.661 (R – 1.23 Zh)2 (heights in feet)

If the height of a radar scanner is 35 meters and it generates an echo at 44miles, the height of the object
generating echo is 190.8 m. When plotting fix at longer ranges using radar ranges, the ranges are unlikely to
cut at the actual position of the ship and give a general indication of the area where the ship is. In such cases,
radar bearings should also be plotted of any peaks that have been detected by radar. It is important to
remember that radar will not necessarily detect an object with poor radar reflection properties even when it is
within the detection range. Similarly maximum detection range, in addition to heights, depends upon power
and performance of the radar, reflective properties of the object, and atmospheric and sea conditions

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POSITION FIXING

Best radar fix can be obtained through two or more ranges. Ranges ahead and astern should be measured
first, followed by beam, as the distances ahead and astern will change more rapidly as opposed to distances
abeam, thus keeping measurement time delay error to minimum. Range should be measured from near side
of the displayed echo or RACON, i.e., the variable range marker VRM should not overlap the displayed echo.
There may be other errors in range. These may be index errors, which are to do with time delays and within
the radar set. Where known, range index error should be available to navigator for application to ranges
measured. Some design factors like oscillator frequency, linearity in radar range rings and non-
synchronisation between VRM and fixed rings cause errors in older designs. Range setting should be
optimum, e.g., range of an object at 2´.5 should be measured at 3´ scale and not 6´. Reflecting properties of
different objects and height of tide may cause errors in range. Bearing accuracy on radar is effected by
horizontal beam width, using longer scale than necessary, heading marker error, aligning of radar antenna,
antenna motor, gyro or transmitting compass error and squint (experienced in scanners fed from the end and
error occurs due to change in frequency of oscillator).Older radars may have centering and parallax errors
associated with cursor. Bearing should be taken through the middle of an isolated object, as well as RACON,
to eliminate beam width error. When taking bearing of headland, it should be from the edge and half beam-
width should be applied.

3.3 CONTROL NAVIGATION IN/NEAR TRAFFIC SEPARATION SCHEMES

 Admiralty charts show both IMO-adopted and national authority schemes. ANM Notice No.17 and
IMO “Ships’ Routeing” should be consulted to determine whether a particular scheme has been
adopted by the IMO.
 TSSs are usually sited where there is a heavy concentration of shipping. Mariners are therefore
reminded of the particular importance of strictly adhering to Rules 5, 6, 7 and 8, which refer to Look-
out, Safe Speed, Risk of Collision, and Action to Avoid Collision. Mariners are also reminded that
except where there are special local rules to the contrary, the other Steering and Sailing Rules
(Section II – Conduct of vessels in sight of one another and Section III – Conduct of vessels in
restricted visibility) apply within a scheme as they do elsewhere at sea. Vessels proceeding in a
TSS do not have priority over crossing traffic.
 Vessels crossing a TSS must do so on a heading as nearly as practicable at right angles to the
direction of traffic flow. This minimises the time a crossing vessel is in the lane irrespective of the
tidal stream, and should lead to a clear encounter situation with vessels passing through the main
traffic lanes.

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 Within the context of Rule 10(d) it is the view of the MCA that neither the density of traffic in a lane
nor restricted visibility are sufficient reasons to justify the use of an Inshore Traffic Zone (ITZ), nor
will the apparent absence of traffic in the ITZ qualify as a reason for not complying with this Rule.
 Vessels may use an ITZ where necessary to seek shelter from weather, and whilst in an ITZ vessels
may be encountered heading in any direction.
 Where a TSS is bordered on both sides by an ITZ, a vessel must not use the ITZ except as
permitted by Rule 10 (d).
 A vessel which needs to anchor, for example because of an engine breakdown or bad visibility, may
do so in a separation zone.
 Vessels fishing within a Scheme are considered to be using the Scheme, and must comply with the
general requirements set out in Rules 10(b) and (c), however, when fishing in a separation zone
they may follow any course.
 The requirement that vessels fishing must not impede the passage of traffic passing through a TSS,
means that they must not operate in such a manner that neither they, nor their gear, seriously
restricts the sea room available to other vessels within a lane, and must take early and substantial
action to avoid any risk of collision developing.
 Rule 8(f) places further obligations upon fishing vessels, with regard to their responsibility not to
impede the passage of any vessel following a traffic lane, and fishing vessels are not relieved from
this obligation in a developing situation where risk of collision may exist. When taking any action
they must, however, take account of the possible manoeuvres of the vessel which is not to be
impeded.
 No specific mention is made in Rule 10(j) of a sailing vessel having an auxiliary engine, however, if
such a vessel cannot follow the routeing procedures under sail because of light or adverse winds,
then she should make use of her engines in order to do so, and should show the appropriate lights,
shapes and sound signals for a power-driven vessel. aids to navigation, wreck removal,
hydrographic surveying and in certain circumstances dredging.
 Many TSSs have Precautionary Areas associated with them, where traffic lanes cross or converge,
so that proper separation of traffic is not possible. Precautionary Areas should be avoided, if
practicable, by ships not making use of the associated schemes or deep-water routes.
Precautionary areas are not part of a TSS, and Rule 10 is not generally applicable, however, ships
should navigate with particular caution within such areas.
 Any vessel observed in a TSS which appears not to be complying with the requirements of the
Scheme should be immediately notified by the best available means. If the TSS is within a Vessel
Traffic Service (VTS) coverage area, the VTS should be notified.
 The international two-letter signal YG meaning “you appear not to be complying with the TSS” may
also be used for this purpose. The master of any vessel receiving this signal by whatever means
should check their course and position and immediately take action to rectify the situation.

PASSAGE PLANNING

 A passage plan and possible contingency arrangements containing all required reporting
information, as well as the reporting points, should be prepared well in advance of reaching the
outer limits of the reporting area. This will avoid last-minute decision-making, and searching for
sources of information, enabling full concentration on traffic and navigation in TSS.
 Mariners should be aware that concentrations of fishing vessels and small craft may be encountered
in the TSS and should navigate with caution. Fishing vessels are reminded of the requirements of
Rule 10(i) and sailing vessels and other vessels of less than 20 meters in length of the requirements
of Rule 10(j) of the COLREGs.

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 Mariners are reminded that there is a concentration of crossing ferry traffic, including high speed
craft, near TSS. These vessels may make course alterations outside the lanes in order to cross
them at right angles.
 Vessels in either traffic lane may have to give way to ferries and other crossing vessels in order to
comply with the Steering and Sailing Rules (Rules 4 – 19) of the COLREGs.
 Surveillance surveys indicate that risk of collision increases if cross channel traffic, shape courses
without due regard to the traffic situation in the adjacent lane. Vessels proceeding along the traffic
lanes, in meeting their obligations under Rules 15 and 16, are often observed making substantial
course alterations and their actions are frequently complicated when traffic converges within a
particular lane. Attention is therefore drawn to the need for cross channel traffic to take into account
this possible situation arising when passage planning. Consideration should also be given to where
the lane is to be crossed so that potential collision risk situations can be anticipated and are not
allowed to develop. Passage planning should be dynamic and include selection and setting of a
course as soon as practicable.
 In two-way routes, including two-way deep-water routes, vessels should, as far as practicable, keep
to the starboard side of the marked route. Vessels using deep-water routes are recommended to
avoid overtaking.
 Master of ships, when planning their passage through the TSS and its approaches, should ensure
that there is an adequate under-keel clearance at the time of passage. To achieve this, allowance
must be made for the effects of squat at the passage speed, for uncertainties in charted depths and
tide levels, and for the effects of waves and swell resulting from local and distant storms.
 In assessing a safe under-keel allowance, masters of vessels constrained by their draught are
strongly advised to consult the Sailing Directions, Mariners’ Routing Guide sand Deep-Draught
Planning Guides published for the area by hydrographic offices, and to be guided by the
recommendations for under-keel allowance contained therein.

INTERNATIONAL REGULATIONS FOR PREVENTING COLLISIONS AT SEA, 1972 (AS

AMENDED BY RESOLUTIONS A464 (XII), A626 (15), A678 (16), A736 (18) AND A.910
(22))

RULE-10: TRAFFIC SEPARATION SCHEMES

(A)THIS
RULE APPLIES TO TRAFFIC SEPARATION SCHEMES ADOPTED BY THE
ORGANIZATION AND DOES NOT RELIEVE ANY VESSEL OF HER OBLIGATION
UNDER ANY OTHER RULE.

Concept of TSS: The purpose of ships’ routeing is to improve the safety of navigation in converging areas and
in areas where the density of traffic is great or where the freedom of movement of shipping is inhibited by
restricted sea-room, the existence of obstructions to navigation, limited depths or unfavourable meteorological
conditions.
Rule 10 adds some extra provisions for traffic management for a number of specially designated areas having
high-density traffic, converging traffic, or some exceptional hazard. In these situations, more conventional
navigation rules do not provide a desirable margin of safety.
The Organization mentioned in the International Rule paragraph (a) is the International Maritime Organization
(IMO), a body of the United Nations headquartered in London. Traffic separation schemes are adopted by the
IMO after a country (or countries) submits a traffic separation scheme proposal, which must meet specific
IMO guidelines. Normally a scheme will not be shown on charts until it has been formally adopted by the IMO.

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The IMO publishes Ships' Routing, which contains design standards and a list (with diagrams and
coordinates) of all adopted traffic separation schemes.
The details of TSS can be found in IMO Ships Routeing Guide.
Other Rules in TSS: All other Rules of the Collision Regulations continue to apply to a vessel using a TSS.
Example – Head on, crossing, overtaking situations, etc are fully applicable in TSS. A power-driven vessel
following a traffic lane is not relieved of her obligation to keep out of the way of a vessel seen on her own
starboard side to be crossing so as to involve risk of collision.

(B) A VESSEL USING A TRAFFIC SEPARATION SCHEME SHALL:

When a vessel is considered to be using a TSS: Within the context of Rule-10:

 She is navigating within the outer limits of the scheme

 She is not crossing the lanes
 She is not engaged in fishing within a separation zone.
 A vessel using an inshore traffic zone is not using the scheme.

(i) PROCEED IN THE APPROPRIATE TRAFFIC LANE IN THE GENERAL DIRECTION OF TRAFFIC FLOW
FOR THAT LANE;
GENERAL DIRECTION OF TRAFFIC LANE: A VESSEL INTENDS TO USE TSS MUST PROCEED IN THE
RIGHT LANE, I.E. ALONG THE GENERAL DIRECTION OF THE LANE. THE GENERAL DIRECTION OF
TRAFFIC FLOW WITHIN A TRAFFIC LANE IS INDICATED BY ARROWS ON THE CHARTS.
(ii) SO FAR AS PRACTICABLE KEEP CLEAR OF A TRAFFIC SEPARATION LINE OR SEPARATION
ZONE;
THE SECOND RULE REQUIRES VESSELS "SO FAR AS PRACTICABLE" NOT TO GET TOO CLOSE TO A
TRAFFIC SEPARATION LINE OR ZONE SO AS NOT TO DRIFT ACCIDENTALLY INTO THE LANE OF
ONCOMING TRAFFIC OR CREATE DOUBT ABOUT WHETHER OR NOT IT IS USING THE TRAFFIC
SEPARATION SCHEME.
(iii) NORMALLY JOIN OR LEAVE A TRAFFIC LANE AT THE TERMINATION OF THE LANE, BUT WHEN
JOINING OR LEAVING FROM EITHER SIDE SHALL DO SO AT AS SMALL AN ANGLE TO THE GENERAL
DIRECTION OF TRAFFIC FLOW AS PRACTICABLE.

The third rule, governing vessels entering or leaving a traffic separation lane, requires a small angle of
approach or departure to differentiate that vessel from one crossing the scheme. (Crossing instructions are in
Rule 10(c).)

(C) A VESSEL SHALL SO FAR AS PRACTICABLE AVOID CROSSING TRAFFIC

LANES, BUT IF OBLIGED TO DO SO SHALL CROSS ON A HEADING AS NEARLY AS
PRACTICABLE AT RIGHT ANGLES TO THE GENERAL DIRECTION OF TRAFFIC
FLOW.

Crossing a traffic lane may be a disturbance to the traffic flow pattern and increase the risk of collision. Many
schemes are short, and you can go around, not through them. Crossing long schemes at right angles to the
general direction of the traffic flow implicates vessel's intentions and minimizes the time the crossing vessel
spends in the scheme. The angle of crossing is determined by the vessel's heading, not its course made
good.
When a crossing vessel encounters a vessel using a traffic separation scheme, the vessel that is required to
keep out of the way is determined by Rule 15 (Crossing Situations).

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Fishing vessels, sailing vessels, and power-driven vessels less than twenty meters in length--see paragraphs
(i) and (j)--that are crossing shall always stay out of the way of a vessel following a traffic separation lane, but
be aware that the larger vessel in the traffic lane does not have absolute rights; see Rule 8(f)(iii).

(D) (i) A VESSEL SHALL NOT USE AN INSHORE TRAFFIC ZONE WHEN SHE CAN
SAFELY USE THE APPROPRIATE TRAFFIC LANE WITHIN THE ADJACENT TRAFFIC
SEPARATION SCHEME. HOWEVER, VESSELS OF LESS THAN 20M IN LENGTH,
SAILING VESSELS AND VESSELS ENGAGED IN FISHING MAY USE THE INSHORE
TRAFFIC ZONE.

Inshore Traffic Zone: A routeing measure comprising a designated area between the landward boundary of a
TSS and the adjacent coast, to be used in accordance with the provisions of Rule 10(d), as amended, of the
International Regulations for Preventing Collisions at Sea (Collision Regulations), 1972. Inshore traffic zones
have been established alongside some traffic separation schemes with the intention of keeping coastal
shipping away from traffic passing through the adjacent traffic lanes. Contrary to this, there are some TSS
following which a ship takes longer time than it would’ve taken to make her passage between two near-by
ports had she followed the inshore traffic zone. But local rules regarding some TSS around the world prohibit
doing so unless proper permission or exemption is taken. A severe fine may be imposed for breaching such
local rules. Mariners should consult with appropriate Sailing Directions, ALRS Volumes, Chart Notes, etc for
the details of the requirements. The Rule recognizes that sailing vessels and small power-driven vessels often
depend on being near the coast.

(ii) NOTWITHSTANDING SUBPARAGRAPH D(I), A VESSEL MAY USE AN INSHORE

TRAFFIC ZONE WHEN EN ROUTE TO OR FROM A PORT, OFFSHORE
INSTALLATION OR STRUCTURE, PILOT STATION OR ANY OTHER PLACE
SITUATED WITHIN THE INSHORE TRAFFIC ZONE OR TO AVOID IMMEDIATE
DANGER.

An OOW should have clear conception that he may use the ISTZ in case of an emergency to avoid an
immediate danger. Example – If a vessel’s steering fails in a busy traffic lane, she could be pulled out of the
lane and head for an anchorage within an ISTZ.

(E) A VESSEL OTHER THAN A CROSSING VESSEL OR A VESSEL JOINING OR

LEAVING A LANE SHALL NOT NORMALLY ENTER A SEPARATION ZONE OR
CROSS A SEPARATION LINE EXCEPT:

Separation Zone or Line: A zone or line separating the traffic lanes in which ships are proceeding in opposite
or nearly opposite directions; or separating a traffic lane from the adjacent sea area; or separating traffic lanes
designated for particular classes of ship proceeding in the same direction.

 IN CASES OF EMERGENCY TO AVOID IMMEDIATE DANGER;

 TO ENGAGE IN FISHING WITHIN A SEPARATION ZONE.

(F) A VESSEL NAVIGATING IN AREAS NEAR THE TERMINATIONS OF TRAFFIC

SEPARATION SCHEMES SHALL DO SO WITH PARTICULAR CAUTION.

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Because of the concentration of converging, diverging and crossing traffics at the termination of a TSS, you
should exercise particular caution, especially when the visibility is restricted.
Paragraph (f) makes it clear that the mariner is also required to proceed with caution near the ends of traffic
separation schemes that do not have precautionary areas.

(G)A VESSEL SHALL SO FAR AS PRACTICABLE AVOID ANCHORING IN A TRAFFIC

SEPARATION SCHEME OR IN AREAS NEAR ITS TERMINATIONS.

The reason for such rule is that anchored vessel in or near a TSS causes traffic congestion and confusion to
mariners.

(H) A VESSEL NOT USING A TRAFFIC SEPARATION SCHEME SHALL AVOID IT BY

AS WIDE A MARGIN AS IS PRACTICABLE.

The smooth operation of a traffic separation scheme depends on the absence of outside disturbances. A
vessel following a traffic lane may get confused seriously by the adjacent traffics outside the TSS. A vessel
not using a traffic separation scheme must stay far enough away that vessels within the scheme are not
obligated, via any other navigation rule--see Rule 8(f)(iii)--to take action inconsistent with the flow of traffic.

(I) A VESSEL ENGAGED IN FISHING SHALL NOT IMPEDE THE PASSAGE OF ANY
VESSEL FOLLOWING A TRAFFIC LANE.

Fishing is permitted within a traffic lane so long as the fishing vessel does not "impede" other vessels
following the traffic lane and does not proceed against the general direction of flow when fishing within a lane.
If the vessel engaged in fishing follows a course that obliges a vessel following the traffic lane to alter course
or speed, then the fishing vessel has impeded the other vessel and is therefore in violation of this
requirement.
A vessel engaged in fishing outside the outer limits of a TSS must not allow her nets to extend into a traffic
lane in such a way as to impede the passage of a vessel following the lane.

(J) A VESSEL OF LESS THAN 20 METERS IN LENGTH OR A SAILING VESSEL

SHALL NOT IMPEDE THE SAFE PASSAGE OF A POWER-DRIVEN VESSEL
FOLLOWING A TRAFFIC LANE.

Here Rule-8(f) comes into picture which has been discussed earlier, i.e. about ‘Impeding the safe passage of
a power driven vessel’.

(K) A VESSEL RESTRICTED IN HER ABILITY TO MANEUVER WHEN ENGAGED IN AN

OPERATION FOR THE MAINTENANCE OF SAFETY OF NAVIGATION IN A TRAFFIC
SEPARATION SCHEME IS EXEMPTED FROM COMPLYING WITH THIS RULE TO THE
EXTENT NECESSARY TO CARRY OUT THE OPERATION.

Note: Explanation for (k) and (l) have been given together below.

(L) A VESSEL RESTRICTED IN HER ABILITY TO MANEUVER WHEN ENGAGED IN AN

OPERATION FOR THE LAYING, SERVICING OR PICKING UP OF A SUBMARINE
CABLE, WITHIN A TRAFFIC SEPARATION SCHEME, IS EXEMPTED FROM
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COMPLYING WITH THIS RULE TO THE EXTENT NECESSARY TO CARRY OUT THE
OPERATION.

Vessels engaged in the maintenance of navigation safety, such as buoy tenders, are exempted only while
they are restricted in their ability to maneuver and only to the extent needed to carry out their work.
But they are normally expected to comply with the provisions of Rule 10 and to either cross traffic lanes at
right angles or proceed along them in the general direction of traffic flow. These vessels must exhibit the lights
or shapes prescribed in Rule 27(b) to indicate their RAM status.
Operations likely to interfere with normal separation scheme traffic are usually promulgates by notices to
mariners through various equipment and services.

SPECIAL SIGNAL

The International Code two letter signal ‘YG’ has the meaning ‘You appear not to be complying with the traffic
separation scheme’. The Master of any vessel receiving the signal by whatever means should take immediate
steps to check his course and position and any further action which may be appropriate to the circumstances.

3.4 MANAGE A BRIDGE TEAM

VOYAGE PLANNING

General requirements

1 The intended voyage shall be planned in advance taking into consideration all pertinent information
and any course laid down shall be checked before the voyage commences.

2 The chief engineer officer shall, in consultation with the master, determine in advance the needs of
the intended voyage, taking into consideration the requirements for fuel, water, lubricants, chemicals,
expendable and other spare parts, tools, supplies and any other requirements.

Planning prior to each voyage

3 Prior to each voyage the master of every ship shall ensure that the intended route from the port of
departure to the first port of call is planned using adequate and appropriate charts and other nautical
publications necessary for the intended voyage, containing accurate, complete and up-to-date information
regarding those navigational limitations and hazards which are of a permanent or predictable nature, and
which are relevant to the safe navigation of the ship.

Verification and display of planned route

4 When the route planning is verified taking into consideration all pertinent information, the planned
route shall be clearly displayed on appropriate charts, and shall be continuously available to the officer in
charge of the watch who shall verify each course to be followed prior to using it during the voyage.

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Deviation from planned route

5 If a decision is made, during a voyage, to change the next port of call of the planned route, or if it is
necessary for the ship to deviate substantially from the planned route for other reasons, then an amended
route shall be planned prior to deviating substantially from the route originally planned.

WATCHKEEPING AT SEA

Principles applying to watch keeping generally

6 Parties shall direct the attention of companies, masters, chief engineer officers and watch keeping
personnel to the following principles which shall be observed to ensure that safe watches are maintained
at all times.

7 The master of every ship is bound to ensure that watch keeping arrangements are adequate for
maintaining a safe navigational watch. Under the master’s general direction, the officers of the
navigational watch are responsible for navigating the ship safely during their periods of duty, when they
will be particularly concerned with avoiding collision and stranding.

8 The chief engineer officer of every ship is bound, in consultation with the master, to ensure that watch
keeping arrangements are adequate to maintain a safe engineering watch.

Protection of marine environment

9 The master, officers and ratings shall be aware of the serious effects of operational or accidental
pollution of the marine environment and shall take all possible precautions to prevent such pollution,
particularly within the framework of relevant international and port regulations.

PRINCIPLES TO BE OBSERVED IN KEEPING A NAVIGATIONAL WATCH

10 The officer in charge of the navigational watch is the master’s representative and is primarily
responsible at all times for the safe navigation of the ship and for complying with the International
Regulations for Preventing Collisions at Sea, 1972.

Look-out

11 A proper look-out shall be maintained at all times in compliance with rule 5 of the International
Regulations for Preventing Collisions at Sea, 1972 and shall serve the purpose of:
maintaining a continuous state of vigilance by sight and hearing as well as by all other available means,
with regard to any significant change in the operating environment;

12 Fully appraising the situation and the risk of collision, stranding and other dangers to navigation; and

13 Detecting ships or aircraft in distress, shipwrecked persons, wrecks, debris and other hazards to safe
navigation.

14 The look-out must be able to give full attention to the keeping of a proper look-out and no other duties
shall be undertaken or assigned which could interfere with that task.

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15 The duties of the look-out and helms person are separate and the helmsperson shall not be
considered to be the look-out while steering, except in small ships where an unobstructed all-round view
is provided at the steering position and there is no impairment of night vision or other impediment to the
keeping of a proper look-out. The officer in charge of the navigational watch may be the sole look-out in
daylight provided that on each such occasion:

.1 The situation has been carefully assessed and it has been established without doubt that it is
safe to do so;

. 2 Full accounts has been taken of all relevant factors including, but not limited to:

 State of weather,
 Visibility,
 Traffic density,
 Proximity of dangers to navigation, and
 The attention necessary when navigating in or near traffic separation schemes; and

3. Assistance is immediately available to be summoned to the bridge when any change in the
situation so requires.

16 In determining that the composition of the navigational watch is adequate to ensure that a proper look-out
can continuously be maintained, the master shall take into account all relevant factors, including those
described in this section of the Code, as well as the following factors:

 Visibility, state of weather and sea;

 Traffic density, and other activities occurring in the area in which the vessel is navigating;

 The attention necessary when navigating in or near traffic separation schemes or other
routeing measures;

 The additional workload caused by the nature of the ship’s functions, immediate operating
requirements and anticipated maneouvers;

 The fitness for duty of any crew members on call who are assigned as members of the watch;

 Knowledge of and confidence in the professional competence of the ship’s officers and crew;

 The experience of each officer of the navigational watch, and the familiarity of that officer with
the ship’s equipment, procedures, and maneuvering capability;

 Activities taking place on board the ship at any particular time, including radio communication
activities and the availability of assistance to be summoned immediately to the bridge when
necessary;

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 The operational status of bridge instrumentation and controls, including alarm systems;

 Rudder and propeller control and ship maneuvering characteristics;

 The size of the ship and the field of vision available from the conning position;

 The configuration of the bridge, to the extent such configuration might inhibit a member of the
watch from detecting by sight or hearing any external development; and

 Any other relevant standard, procedure or guidance relating to watch keeping arrangements
and fitness for duty which has been adopted by the Organization.

Watch arrangements

17 When deciding the composition of the watch on the bridge, which may include appropriately qualified
ratings, the following factors, inter alia, shall be taken into account:

 At no time shall the bridge be left unattended;

 Weather conditions, visibility and whether there is daylight or darkness;
 Proximity of navigational hazards which may make it necessary for the officer in charge of the
watch to carry out additional navigational duties;
 Use and operational condition of navigational aids such as radar or electronic position-
indicating devices and any other equipment affecting the safe navigation of the ship;
 Whether the ship is fitted with automatic steering;
 Whether there are radio duties to be performed;
 Unmanned machinery space (UMS) controls, alarms and indicators provided on the bridge,
procedures for their use and limitations; and
 Any unusual demands on the navigational watch that may arise as a result of special
operational circumstances.

Taking over the watch

18 The officer in charge of the navigational watch shall not hand over the watch to the relieving officer if
there is reason to believe that the latter is not capable of carrying out the watch keeping duties effectively,
in which case the master shall be notified.

19 The relieving officer shall ensure that the members of the relieving watch are fully capable of performing
their duties, particularly as regards their adjustment to night vision. Relieving officers shall not take over
the watch until their vision is fully adjusted to the light conditions.

20 Prior to taking over the watch relieving officers shall satisfy themselves as to the ship’s estimated or true
position and confirm its intended track, course and speed, and UMS controls as appropriate and shall
note any dangers to navigation expected to be encountered during their watch.

21 Relieving officers shall personally satisfy themselves regarding the:

 Standing orders and other special instructions of the master relating to navigation of the ship;
 Position, course, speed and draught of the ship;

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 Prevailing and predicted tides, currents, weather, visibility and the effect of these factors upon
course and speed;
 Procedures for the use of main engines to manoeuvre when the main engines are on bridge
control; and

Navigational situation, including but not limited to:

 The operational condition of all navigational and safety equipment being used or likely to be
used during the watch,
 The errors of gyro and magnetic compasses,
 The presence and movement of ships in sight or known to be in the vicinity,
 The conditions and hazards likely to be encountered during the watch, and
 The possible effects of heel, trim, water density and squat on under keel clearance.

22 If at any time the officer in charge of the navigational watch is to be relieved when a manoeuvre or other
action to avoid any hazard is taking place, the relief of that officer shall be deferred until such action has
been completed.

Performing the navigational watch

23 The officer in charge of the navigational watch shall:

 Keep the watch on the bridge;

 In no circumstances leave the bridge until properly relieved;
 Continue to be responsible for the safe navigation of the ship, despite the presence of the
master on the bridge, until informed specifically that the master has assumed that responsibility
and this is mutually understood; and
 Notify the master when in any doubt as to what action to take in the interest of safety.

24 During the watch the course steered, position and speed shall be checked at sufficiently frequent
intervals, using any available navigational aids necessary, to ensure that the ship follows the planned
course.

25 The officer in charge of the navigational watch shall have full knowledge of the location and operation of
all safety and navigational equipment on board the ship and shall be aware and take account of the
operating limitations of such equipment.

26 The officer in charge of the navigational watch shall not be assigned or undertake any duties which would
interfere with the safe navigation of the ship.

27 Officers of the navigational watch shall make the most effective use of all navigational equipment at their
disposal.

28 When using radar, the officer in charge of the navigational watch shall bear in mind the necessity to
comply at all times with the provisions on the use of radar contained in the International Regulations for
Preventing Collisions at Sea, in force.

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29 In cases of need the officer in charge of the navigational watch shall not hesitate to use the helm, engines
and sound signaling apparatus. However, timely notice of intended variations of engine speed shall be
given where possible or effective use made of UMS engine controls provided on the bridge in accordance
with the applicable procedures.

30 Officers of the navigational watch shall know the handling characteristics of their ship, including its
stopping distances, and should appreciate that other ships may have different handling characteristics.

31. A proper record shall be kept during the watch of the movements and activities relating to the navigation
of the ship.

32 It is of special importance that at all times the officer in charge of the navigational watch ensures that a
proper look-out is maintained. In a ship with a separate chart room the officer in charge of the
navigational watch may visit the chart room, when essential, for a short period for the necessary
performance of navigational duties, but shall first ensure that it is safe to do so and that proper look-out is
maintained.

33 Operational tests of shipboard navigational equipment shall be carried out at sea as frequently as
practicable and as circumstances permit, in particular before hazardous conditions affecting navigation
are expected. Whenever appropriate, these tests shall be recorded. Such tests shall also be carried out
prior to port arrival and departure.

34 The officer in charge of the navigational watch shall make regular checks to ensure that:

 The person steering the ship or the automatic pilot is steering the correct course;
 The standard compass error is determined at least once a watch and, when possible, after any
major alteration of course; the standard and gyro-compasses are frequently compared and
repeaters are synchronized with their master compass;
 The automatic pilot is tested manually at least once a watch;
 The navigation and signal lights and other navigational equipment are functioning properly;
 The radio equipment is functioning properly in accordance with paragraph 86 of this section;
and
 The UMS controls, alarms and indicators are functioning properly.

35 The officer in charge of the navigational watch shall bear in mind the necessity to comply at all times with
the requirements in force of the International Convention for the Safety of Life at Sea, (SOLAS) 1974. The
officer of the navigational watch shall take into account:

 The need to station a person to steer the ship and to put the steering into manual control in
good time to allow any potentially hazardous situation to be dealt with in a safe manner; and
 That with a ship under automatic steering it is highly dangerous to allow a situation to develop
to the point where the officer in charge of the navigational watch is without assistance and has
to break the continuity of the look-out in order to take emergency action.

36 Officers of the navigational watch shall be thoroughly familiar with the use of all electronic navigational
aids carried, including their capabilities and limitations, and shall use each of these aids when appropriate
and shall bear in mind that the echo-sounder is a valuable navigational aid.

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37 The officer in charge of the navigational watch shall use the radar whenever restricted visibility is
encountered or expected, and at all times in congested waters having due regard to its limitations.

38 The officer in charge of the navigational watch shall ensure that range scales employed are changed at
sufficiently frequent intervals so that echoes are detected as early as possible. It shall be borne in mind
that small or poor echoes may escape detection.

39 Whenever radar is in use, the officer in charge of the navigational watch shall select an appropriate range
scale and observe the display carefully, and shall ensure that plotting or systematic analysis is
commenced in ample time.

40 The officer in charge of the navigational watch shall notify the master immediately:

 If restricted visibility is encountered or expected;

 If the traffic conditions or the movements of other ships are causing concern;

 If difficulty is experienced in maintaining course;

 On failure to sight land, a navigation mark or to obtain soundings by the expected time;

 If, unexpectedly, land or a navigation mark is sighted or a change in soundings occurs;

 On breakdown of the engines, propulsion machinery remote control, steering gear or any
essential navigational equipment, alarm or indicator;

 If the radio equipment malfunctions;

 In heavy weather, if in any doubt about the possibility of weather damage;

 If the ship meets any hazard to navigation, such as ice or a derelict; and

 In any other emergency or if in any doubt.

40 Despite the requirement to notify the master immediately in the foregoing circumstances, the officer in
charge of the navigational watch shall in addition not hesitate to take immediate action for the safety of
the ship, where circumstances so require.

42 The officer in charge of the navigational watch shall give watch keeping personnel all appropriate
instructions and information which will ensure the keeping of a safe watch, including a proper look-out.

Watch keeping under different conditions and in different areas.

Clear weather
43 The officer in charge of the navigational watch shall take frequent and accurate compass bearings of
approaching ships as a means of early detection of risk of collision and bear in mind that such risk may
sometimes exist even when an appreciable bearing change is evident, particularly when approaching a
very large ship or a tow or when approaching a ship at close range. The officer in charge of the
navigational watch shall also take early and positive action in compliance with the applicable International

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Regulations for Preventing Collisions at Sea, 1972 and subsequently check that such action is having the
desired effect.

44 In clear weather, whenever possible, the officer in charge of the navigational watch shall carry out radar
practice.

Restricted visibility
45 When restricted visibility is encountered or expected, the first responsibility of the officer in charge of the
navigational watch is to comply with the relevant rules of the International Regulations for Preventing
Collisions at Sea, 1972 with particular regard to the sounding of fog signals, proceeding at a safe speed
and having the engines ready for immediate manoeuvre. In addition, the officer in charge of the
navigational watch shall:

 Inform the master;

 Post a proper look-out;
 Exhibit navigation lights; and
 Operate and use the radar.

In hours of darkness

46 The master and the officer in charge of the navigational watch when arranging look-out duty shall have
due regard to the bridge equipment and navigational aids available for use, their limitations; procedures
and safeguards implemented.

Coastal and congested waters

47 The largest scale chart on board, suitable for the area and corrected with the latest available information,
shall be used. Fixes shall be taken at frequent intervals, and shall be carried out by more than one
method whenever circumstances allow.

48 The officer in charge of the navigational watch shall positively identify all relevant navigation marks.

Navigation with pilot on board

49 Despite the duties and obligations of pilots, their presence on board does not relieve the master or officer
in charge of the navigational watch from their duties and obligations for the safety of the ship. The master
and the pilot shall exchange information regarding navigation procedures, local conditions and the ship’s
characteristics. The master and/or the officer in charge of the navigational watch shall co-operate closely
with the pilot and maintain an accurate check on the ship’s position and movement.

50 If in any doubt as to the pilot’s actions or intentions, the officer in charge of the navigational watch shall
seek clarification from the pilot and, if doubt still exists, shall notify the master immediately and take
whatever action is necessary before the master arrives.

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BRIDGE RESOURCE MANAGEMENT

1 Companies should issue guidance on proper bridge procedures, and promote the use of checklists
appropriate to each ship taking into account national and international guidance.

2 Companies should also issue guidance to masters and officers in charge of the navigational watch on
each ship concerning the need for continuously reassessing how bridge-watch resources are being
allocated and used, based on bridge resource management principles such as the following:

 A sufficient number of qualified individuals should be on watch to ensure all duties can be
performed effectively;
 All members of the navigational watch should be appropriately qualified and fit to perform
their duties efficiently and effectively or the officer in charge of the navigational watch should
take into account any limitation in qualifications or fitness of the individuals available when
making navigational and operational decisions;
 Duties should be clearly and unambiguously assigned to specific individuals, who should
confirm that they understand their responsibilities;
 Tasks should be performed according to a clear order of priority;
 No member of the navigational watch should be assigned more duties or more difficult tasks
than can be performed effectively;

 Individuals should be assigned at all times to locations at which they can most efficiently and
effectively perform their duties, and individuals should be reassigned to other locations as
circumstances may require;

 Members of the navigational watch should not be assigned to different duties, tasks or
locations until the officer in charge of the navigational watch is certain that the adjustment can
be accomplished efficiently and effectively;

 Instruments and equipment considered necessary for effective performance of duties

should be readily available to appropriate members of the navigational watch;

 Communications among members of the navigational watch should be clear, immediate,

reliable, and relevant to the business at hand;

 Non-essential activity and distractions should be avoided, suppressed or removed;

 All bridge equipment should be operating properly and if not, the officer in charge of the
navigational watch should take into account any malfunction which may exist in making
operational decisions;

 All essential information should be collected, processed and interpreted, and made
conveniently available to those who require it for the performance of their duties;

 Non-essential materials should not be placed on the bridge or any work surface; and

 Members of the navigational watch should at all times be prepared to respond efficiently and
effectively to changes in circumstances.

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CHAPTER 4

PLAN AND CO-ORDINATE SEARCH AND RESCUE

4.1 RESPOND TO A DISTRESS MESSAGE

Methods of Distress Notification

 An alarm signal or a distress call from another vessel at sea, either directly or by relay.
 A distress call or message from aircraft. This usually occurs by relay from a CRS.
 Alert sent from a vessel's alerting equipment and then relayed shoreto- ship.
 Visual signals or sound signals from a nearby distressed craft.

Immediate Action

 The following immediate action should be taken by any ship receiving a distress message:
 Acknowledge receipt of message.
 Gather the following information from the craft in distress if possible:
 Position of distressed craft
 Distressed craft's identity, call sign, and name
 Number of POBs
 Nature of the distress or casualty
 Type of assistance required
 Number of victims, if any
 Distressed craft's course and speed
 Type of craft, and cargo carried
 Any other pertinent information that might facilitate the rescue
 Maintain a continuous watch on the following international frequencies, if equipped to do so:
 500 kHz (radiotelegraphy)
 2182 kHz (radiotelephony)
 156.8 MHz FM (Channel 16, radiotelephony) for vessel distress
 121.5 MHz AM (radiotelephony) for aircraft distress
 After 1 February 1999, vessels subject to the SOLAS Convention must comply with applicable
equipment carriage and monitoring requirements
 SOLAS communications equipment is referred to as Global Maritime Distress and Safety System
(GMDSS) equipment, and includes:
 Inmarsat ship earth stations
 VHF, MF, and HF digital selective calling (DSC) radios
 Maritime safety information receivers like NAVTEX and Safety NET
 Hand-held VHF equipment
 Emergency position-indicating radio beacons (EPIRBs)
 Search and rescue radar transponders (SARTs)
 Any vessel carrying GMDSS-compatible equipment should use it as intended, and must be
prepared at all times to receive distress alerts with it (see figures on pages 2-3 and 2-4).
 Vessels should maintain communications with the distressed craft while attempting to advise the
SAR system of the situation.

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 The following information should be communicated to the distressed craft:

 Own vessel's identity, call sign, and name
 Own vessel's position
 Own vessel's speed and estimated time of arrival (ETA) to distressed craft site
 Distressed craft's true bearing and distance from ship.
 Use all available means to remain aware of the location of distressed craft (such as radar plotting,
chart plots, Global Positioning System (GPS)).

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 When in close proximity, post extra look-outs to keep distressed craft in sight.
 The ship or CRS co-coordinating distress traffic should establish contact with the SMC and
pass on all available information, updating as necessary.

Proceeding to the Area of Distress

 Establish a traffic co-coordinating system among vessels proceeding to the same area of
distress.
 Maintain active radar plots on vessels in the general vicinity.
 Estimate the ETAs to the distress site of other assisting vessels.
 Assess the distress situation to prepare for operations on-scene.

On-Board Preparation

 A vessel en route to assist a distressed craft should have the following equipment ready for
possible use:

Life-saving and rescue equipment:

 Iifeboat
 Inflatable liferaft
 Lifejackets
 Survival suits for the crew
 Lifebuoys
 Breeches buoys
 Portable VHF radios for communication with the ship and boats deployed
 Line-throwing apparatus
 Buoyant lifelines
 Hauling lines
 Non-sparking boat hooks or grappling hooks
 Hatchets
 Rescue baskets
 Litters
 Pilot ladders
 Scrambling nets
 Copies of the International Code of Signals
 Radio equipment operating on MF/HF and/or VHF/UHF and capable of communicating with
the SMC and rescue facilities, and with a facility for direction finding (DF)
 Supplies and survival equipment, as required
 Fire-fighting equipment
 Portable ejector pumps
 Binoculars
 Cameras
 Bailers and oars.

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Signaling equipment:

 Signaling lamps
 Searchlights
 Torches
 Flare pistol with color-coded signal flares
 Buoyant VHF/UHF marker beacons

 Floating lights

 Smoke generators
 Flame and smoke floats
 Dye markers;
 Loud hailers.

Preparations for medical assistance, including:

 Stretchers
 Blankets
 Medical supplies and medicines
 Clothing
 Food
 Shelter.

Miscellaneous equipment:

 If fitted, a gantry crane for hoisting on each side of ship with a cargo net for recovery of
survivors.
 Line running from bow to stern at the water's edge on both sides for boats and craft to secure
alongside.
 On the lowest weather deck, pilot ladders and manropes to assist survivors boarding the
vessel.
 Vessel's lifeboats ready for use as a boarding station.
 Line-throwing apparatus ready for making connection with either ship in distress or survival
craft.
 Floodlights set in appropriate locations, if recovery at night.

Vessels Not Assisting

The master deciding not to proceed to the scene of a distress due to sailing time involved and in the
knowledge that a rescue operation is under way should:
 Make an appropriate entry in the ships’ log-book.
 If the master had previously acknowledged and responded to thealert, report the decision not
to proceed to the SAR service concerned.
 Consider reports unnecessary if no contact has been made with the SAR service.
 Reconsider the decision not to proceed nor report to the SAR service when vessel in distress
is far from land or in an area where density of shipping is low.

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4.2 CO-ORDINATE SEARCH AND RESCUE OPERATION

Requirements for Co-ordination

When a SAR incident occurs, an SMC will normally be designated, within an RCC or RSC. The SMC will
obtain SAR facilities, plan SAR operations, and provide overall co-ordination. The SMC may also designate
an OSC to provide co-ordination at the scene to carry out plans to locate and rescue survivors. If no SMC has
been designated or communications between the SMC and OSC are lost, the OSC may need to perform
some additional functions normally handled by an SMC. It may be necessary to designate a vessel OSC for
surface activities and an aircraft co-ordinator (ACO) for aircraft activities if vessel-aircraft communications on-
scene are not practical.

Note: In practice, the terms RCC and SMC are often used interchangeably due to their close association.

When a vessel or aircraft becomes aware of a SAR incident directly, it should alert the appropriate RCC or
RSC as follows:
 The RCC or RSC responsible for the SRR where the incident occurred
 The nearest RCC or RSC
 Any RCC or RSC which can be reached; or
 Any communications facility (e.g., alerting post).
 The first facility to arrive in the vicinity of the SAR incident should assume OSC duties and, if
necessary, SMC duties, until an SMC has-been designated, and retain OSC duties until the
SMC has designated an OSC.
 For the maritime environment, ship masters typically perform the OSC function due to ship
endurance on-scene unless more capable SRUs are available.

Co-ordination by Land-Based Authorities

 SAR operations are normally co-ordinated from specially equipped operational centers or
RCCs, staffed 24 hours a day with trained personnel. The working language for these centers
should be English.
 Each RCC has an associated SRR. The SRR might be divided into sub regions with
associated RSCs.
 Land-based communication facilities include:
 Land earth stations (LESs)
 COSPAS-SARSAT Mission Control Centres with Local User Terminals (LUTs)
 Independent CRSs or CRSs associated with the RCCs
 ATS units
 Mobile phone networks
 Internet
 Public telephone alerting systems.
 LESs may also be referred to as aeronautical ground earth stations
 (GESs) or maritime coast earth stations (CESs)

On-Scene Co-ordination

 The types of facilities involved in the response and the region of the SAR incident affect on-
scene co-ordination.

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 Available facilities may include:

 designated SRUs
 Civil aircraft and vessels, military and naval or other facilities with SAR capability.
 In remote regions, SAR aircraft may not always be available to participate.
 In most oceanic regions, ships will normally be available, depending on shipping density.
 Ships may receive information from land-based SAR authorities or by monitoring distress
traffic.
 No advice received from these authorities can set aside the duties of any master as set forth
in regulation V/33 of SOLAS 1974 (see appendix A).

Designation of On-Scene Coordinator (OSC)

 When two or more SAR facilities conduct operations together, the SMC should designate an
OSC.
 If this is not practicable, facilities involved should designate, by mutual agreement, an OSC.
 This should be done as early as practicable and preferably before arrival within the search
area.
 Until an OSC has been designated, the first facility arriving at the scene should assume the
duties of an OSC.
 When deciding how much responsibility to delegate to the OSC, the SMC normally considers
the communications and personnel capabilities of the facilities involved.
 The poorer the communications, the more authority the OSC will need to initiate actions.

OSC Duties

 Co-ordinate operations of all SAR facilities on-scene.

 Receive the search action plan or rescue plan from the SMC or plan the search or rescue
operation, if no plan is otherwise available.
 Modify the search action or rescue action plan as the situation on scene dictates, keeping the
SMC advised (do in consultation with the SMC when practicable).
 Co-ordinate on-scene communications.
 Monitor the performance of other participating facilities.
 Ensure operations are conducted safely, paying particular attention to maintaining safe
separations among all facilities both surface and air.
 Make periodic situation reports (SITREPs) to the SMC. The standard SITREP format may be
found in appendix D. SITREPs should include but not be limited to:
 weather and sea conditions
 the results of search to date
 any actions taken
 any future plans or recommendations.
 Maintain a detailed record of the operation:
 on-scene arrival and departure times of SAR facilities, other vessel sand aircraft engaged in
the operation
 areas searched
 track spacing used
 sightings and leads reported
 actions taken
 results obtained.
 Advise the SMC to release facilities no longer required.

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 Report the number and names of survivors to the SMC.

 Provide the SMC with the names and designations of facilities with survivors aboard.
 Report which survivors are in each facility.
 Request additional SMC assistance when necessary (for example, medical evacuation of
seriously injured survivors).

Designation of Aircraft Co-ordinator (ACO)

 When multiple aircraft conduct SAR operations, the SMC may designate an ACO in addition
to an OSC.
 If this in not practicable, the OSC may designate an ACO.
 Generally, the ACO is responsible to the SMC and co-ordinates closely with the OSC.
 Typically, the SMC or the OSC, as the case may be, would remain in overall charge.
 When deciding how much responsibility to delegate to the ACO, the SMC considers the mix
of radios, radar, and trained personnel capabilities of the facilities involved.
 The ACO may be a fixed-wing aircraft, a helicopter, a ship, a fixed structure such as an oil rig,
or an appropriate land unit.
 Flight safety of SAR aircraft is a primary concern of the ACO.

ACO Duties

 Maintain flight safety:

 Maintain safe separation of aircraft
 Ensure common pressure setting used
 Advise the SMC of on-scene weather implications
 Determine aircraft entry and departure points and altitudes
 Filter radio messages to and from SAR aircraft
 Ensure frequencies are used in accordance with SMC directives
 Co-ordinate with adjacent area control centres (ACCs) and airfields.
 Prioritize and allocate tasks:
 Ensure air facilities are aware of the SMC/OSC overall plan
 Monitor and report search area coverage
 With appropriate SMC/OSC authority, identify emerging tasks and direct SAR aircraft to meet
them.
 Co-ordinate the coverage of search areas:
 Respond to changing factors on-scene and supervise effectiveness of searches
 Co-ordinate aircraft refueling
 Advise SMC/OSC on maintaining continuity.
 Make periodic consolidated reports (SITREPs) of SAR aircraft to the SMC and the OSC, as
appropriate. The standard S1TREP format maybe found in appendix D.
 Work closely with the OSC:
 Assist in execution of SMC directives
 Maintain communications
 Advice on how the ACO can assist.

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Joining Entry Report

Airborne SRUs should make a standard joining entry report to the ACO when entering a search and rescue
mission area, including:
 Call Sign;
 Nationality;
 Type (specify fixed-wing or helicopter and type);
 Position;
 Altitude (on pressure setting used);
 ETA (at relevant point or search area);
 Endurance on scene; and
 Remarks (specific equipment or limitations).

SAR Operation Risks

 Safe and effective SAR operations depend on co-ordinated team work and sound risk
assessment.
 Saving distressed persons, and the safety of assisting personnel, should both be of concern
to the OSC.
 The leaders (captain, pilot-in-command, or OSC) must ensure that personnel perform
properly as a team with a common mission.
 Mishaps often follow a chain of errors that can start with mistakes made during SAR planning
and lead to poor decisions during operations.
 Team safety is supported by:
 Proficiency in keeping everyone informed
 Matching resource capabilities to tasks
 Detecting and avoiding errors early
 Following standard procedures
 Adjusting to non-standard activities.
 Search and rescue action plans provided by the SMC are onlyguidance for the OSC and SAR
facilities on-scene.
 The OSC may adjust the plans, based on the situation, and informthe SMC (do in
consultation with the SMC when practicable)
 SAR facilities should keep the OSC advised of any difficulties or hazards encountered.
 The risks inherent in any SAR response must be considered against the chances for success
and the safety of SAR personnel.

Some practical concerns for assessing the situation include:

 Is the distressed craft in immediate danger of causing harm or placing the rescue facility in
jeopardy?
 Can the rescue facility handle the weather conditions?
 Has the distressed craft given enough information to prepare the assisting vessel to aid in the
rescue?
 Can the assisting facility realistically be of assistance?

 If recovery of a large number of survivors is a factor:

 Can the rescue facility accommodate them in regards to food, shelter, clothing, living
space?

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 Will the craft performing the rescue be stable with the survivors on-board?
 If helicopter operations are a factor:
 Is the vessel's construction suitable for a vessel-aircraft joint operation?
 Does the rescue facility have enough crew members available to assist?

Communications
On-Scene Communications

The OSC should ensure that reliable communications are maintained on-scene.
 Normally, the SMC will select SAR-dedicated frequencies for use on scene, inform the OSC
or SAR facilities, and establish communications with adjacent RCCs and parent agencies of
SAR facilities as appropriate.
 The OSC should maintain communications with all SAR facilities and the SMC
 A primary and secondary frequency should be assigned for on scene communications.
 SAR facilities should report to the OSC on an assigned frequency.
 If a frequency shift is carried out, instructions should be provided about what to do if intended
communications cannot be re established on the new frequency
 All SAR facilities should carry a copy of the International Code of Signals (INTERCO), which
contains communications information internationally recognized by aircraft, vessels, and
survivors.

OSC Communications with RCC or RSC

Situation Reports

 The OSC uses SITREPs to keep the SMC informed of on-scene mission progress and
conditions, and addresses SITREPs to the SMC unless otherwise directed. Search facilities
use SITREPs to keep the OSC informed.
 The SMC uses SITREPs to keep superiors, other RCCs and RSCs, and any other interested
agencies informed
 Where pollution or threat of pollution exists from the vessel or aircraft casualty, the agency
tasked with environmental protection should be an information addressee on all SITREPs
 Provide earliest notice of an emergency (short form)
 Pass urgent essential details when requesting assistance (short form)
 Pass amplifying or updating information during SAR operations(full form).
 Initial SlTREPs should be transmitted as soon as details of an incident become clear enough
to indicate SAR involvement.
 SlTREPs should not be delayed unnecessarily for confirmation of all details
 Further SlTREPs should be issued as soon as other relevant information is obtained
 Information already passed should not be repeated
 During prolonged operations, "no change" SlTREPs should be issued at intervals of about
three hours to reassure recipients that nothing has been missed
 When the incident is concluded, a "final" SITREP should be issued as confirmation.
 A standard SITREP format is shown in appendix D of IAMSAR vol3.
 Each SITREP concerning the same incident should be numbered sequentially.
 SlTREPs prepared on-scene usually provide the following information:
Identification
 Usually in the subject line
 The SITREP number
 Identification of the distressed craft

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 A one- or two-word description of the emergency

 Numbered sequentially throughout the case
 When an OSC is relieved on-scene, the new OSC continues theSITREP numbering
sequence

Situation
 A description of the case
 The conditions that affect the case
 Any amplifying information that will clarify the problem
 After the first SITREP, only changes to the original reported situation need be included

Action taken
 A report of all action taken since the last report, including results of such action
 When an unsuccessful search has been conducted, the report includes:
 The areas searched
 Hours searched
 Factors that may have decreased search effectiveness, such as weather or equipment
difficulties
Future plans
 Description of actions planned for future execution
 Recommendations
 Request for additional assistance

Status of case
 This is normally used only on the final SITREP to indicate that the case is closed or that
search is suspended pending further developments.

RCC and RSC Communications

Maritime Radio Telex

 RCCs and RSCs may use radio telex for shore-to-ship distress traffic.
 Radio telex is sometimes called radio teletype (RTT) or narrow-band direct printing (NBDP).
 Telex messages may be sent via satellite or terrestrial radio.
 Radio telex services should be indicated in the International Telecommunication Union (ITU)
List of Coast Stations.
 Shore-to-ship telex messages are on predetermined frequencies, and mostly at
predetermined times.
 The frequencies for radio telex are:
 490 kHz,
 518 and 4209.5 kHz (international NAVTEX)
 2174.5 kHz.

Maritime Safety Information

 NAVTEX is used to promulgate navigation and safety warnings to vessels, and may be used
by SAR personnel for SAR-related broadcasts.
 The World Wide Navigational Warning System (WWNWS) is for long-range NAVAREA
warnings and coastal NAVTEX warnings.

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 It provides for globally co-ordinated transmissions with NAVAREA Co-ordinators for each
NAVAREA.
 Warnings which SAR personnel may send over WWNWS include:
 Distress alerts
 Information about overdue or missing aircraft or vessels.
 Collectively, these types of alerts, combined with navigation and meteorological warnings, are
called maritime safety information (MSI).
 Inmarsat is also used to broadcast MSI via Safety NET.
 Safety NET provides an automatic, global method of broad casting SAR messages to vessels
in both fixed and variable geographic areas. A similar service of Inmarsat called Fleet NET
can be used to send shore-to-ship messages to predetermined groups of vessels.
 RCCs normally relay distress alerts over both NAVTEX and Safety NET.
 Normally, SAR broadcasts over Safety NET are sent to all vessels within a desired radius of a
specified position.
 It may be faster to first see whether an appropriate ship can be identified via a ship reporting
system, and contacted, before doing a SAR broadcast.

Radio Telegraph (WT)

 Radio telegraph is a Morse Code service provided in the MF and HF maritime bands. For
distress alerting, it is used on the frequencies500 kHz and 8364 kHz.
 After 1 February 1999, SOLAS vessels are not required to continuous of the service.
 This service overcomes language barriers, but it depends upon trained radio operators.
 WT transmissions other than distress calls are supposed to be kept to one minute or less.
 Ship-to-shore WT working frequencies are 425, 454, 458, 468, 480,and 512 kHz.
 During their hours of service, ships are supposed to watch on 500kHz for three minutes twice
per hour beginning at h + 15 and h + 45by an operator using headphones or a loudspeaker.
 During these periods of silence, only distress, urgency, and safety signals are permitted.

Phonetic Alphabet and Figure Code

 The phonetic alphabet and figure code is sometimes necessary to use when speaking or
spelling out call signs, names, search are designations, abbreviations, etc.
 For a complete listing of the phonetic alphabet, figure code, and Morse signals, obtains a
copy of the International Code of Signals.

Radio Communication Frequencies for Distress Purposes

 The frequencies in the following tables are available for safety purposes, distress
communications, and SAR operations.

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Maritime

Ships transmitting a distress message on any of the above frequencies should use the appropriate alarm
signals before transmitting the message until contact has been established.

Aeronautical
The aeronautical frequencies 3023 kHz and 5680 kHz may be used for communications by ships and
participating CRSs engaged in coordinated SAR operations. However, since these frequencies are not
continuously monitored, shore authorities may be needed to help establish communications on these
frequencies.

Land
 Land SAR can be conducted for many types of incidents, ranging from a downed aircraft to a
hiker lost in the wilderness. Land facilities and aeronautical facilities may conduct co-
ordinated land searches. Since each normally operates on different radio frequencies,
advance co-ordination amongst local agencies may be necessary to establish effective
communications.
 Aircraft typically have at least one radio, so it may be easiest for the air facility and land
facility to use an aeronautical frequency.
 If the land facility does not have a portable aircraft radio, then communications may be
provided by equipping an aircraft with a radio operating on ground frequencies.

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4.3 EXECUTE A SEARCH AND RESCUE OPERATION

For surface and aircraft facilities to search effectively, search pattern sand procedures must be pre-
planned so ships and aircraft can cooperation co-ordinated operations with the minimum risks and
delay.
Standard search patterns have been established to meet varying circumstances.

Responsibilities of OSC

The OSC should obtain a search action plan from the SMC via the RCC or RSC as soon as possible.
Normally, search planning is performed using trained personnel, advanced search planning techniques, and
information about the incident or distressed craft not normally available to the OSC. However, the OSC may
still need to plan a search under some circumstances. Search operations should commence as soon as
facilities are available at the scene. If a search plan has not been provided by the SMC, the OSC should do
the planning until an SMC assumes the search planning function. Simplified techniques are presented below.

Modify search plans based on changes in the on-scene situation, such as:
 Arrival of additional assisting facilities
 Receipt of additional information
 Changes in weather, visibility, lighting conditions, etc.
 In case of language difficulties, the International Code of Signals and IMO Standard Marine
Communication Phrases should be used.
 On assuming the duty, the OSC should inform the appropriate CRS or ATS unit and keep it
informed of developments at regular intervals.
 The OSC should keep the SMC informed at regular intervals and whenever the situation has
changed.

Planning the Search

Datum

It will be necessary to establish a datum, or geographic reference, for the area to be searched. The following
factors should be considered:
 Reported position and time of the SAR incident
 Any supplementary information such as DF bearings or sightings
 Time interval between the incident and the arrival of SAR facilities
 Estimated surface movements of the distressed craft or survival craft, depending on drift (The two
figures following this discussion are used in calculating drift.) The datum position for the search is
found as follows:
 Drift has two components: leeway and total water current
 Leeway direction is downwind
 Leeway speed depends on wind speed
 The observed wind speed when approaching the scene may be used for estimating
leeway speed of liferafts by using the graph following this discussion (Persons in the water
(PIVV) have no leeway while liferaft stability and speed vary with or without drogue or
ballast.)
 Total water current may be estimated by computing set and drift when approaching the
scene
 Drift direction and speed is the vector sum of leeway and total water current

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 Drift distance is drift speed multiplied by the time interval between the incident time, or time of the
last computed datum, and the commence search time
 Datum position is found by moving from the incident position, or last computed datum position, the
drift distance in the drift direction and plotting the resulting position on a suitable chart.

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Visual Search

 Individual search patterns have been designed so that an OSC can rapidly initiate a search by one
or more craft.
 There will be a number of variables that cannot be foreseen. Search patterns based on visual
search have been established which should meet many circumstances. They have been selected
for simplicity and effectiveness and are discussed later in this section.

Track Spacing

 Most search patterns consist of parallel tracks or sweeps covering a rectangular area. The
distance between adjacent tracks is called the track spacing.
 Recommended uncorrected track spacing for merchant vessels are provided in the table following
this discussion. Correction factors based on weather conditions and search object are provided in
the table after the track spacing table. Multiplying the uncorrected track spacing (Su) by the
appropriate weather correction factor (fw)produces the recommended track spacing (S):
 S = Su x fw
 Changes in weather, number of assisting craft, etc., may occur, making it prudent to alter the track
spacing.
 The SMC must ensure that all searching ships and aircraft maintain safe separations from one
another and accurately follow their assigned search patterns.

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 The track spacing shown in the tables above are recommended for use with all the search patterns
shown in this Volume except for the sector search pattern.
 The table takes into account the type of search object and the meteorological visibility.
 Other factors may also be considered, including sea conditions, time of day, position of the sun,
effectiveness of observers, etc.

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Searching Speed (V)

 To carry out a parallel sweep search in a co-ordinated manner, all facilities should proceed at the
same speed, as directed by the OSC.
 This should normally be the maximum speed of the slowest ship present.
 In restricted visibility, the OSC will normally order a reduction in searching speed.

Search Area (A)

 Compute the search radius (R), using one of the following two methods:
 If the search must commence immediately, assume R = 10 NM
 If time is available for computation:
 Compute the area a craft can cover in a certain amount of time(T) by the formula: A = S x V x T
 The total amount of area (At) which can be covered by several craft is the sum of the areas
each craft can cover: At = A1+A2+A3 + ...if all craft are searching at the same speed for the
same amount of time, then: At = N x A where N is the number of search craft
 the search radius (R) of the circle is one-half the square root ofthe search area:
 Plot the search area:
 Draw a circle centered on datum with radius R.
 Using tangents to the circle, form a square as shown below
 If several facilities will be searching at the same time, divide the square into sub-areas of the
appropriate size and assign search facilities accordingly.

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Search Patterns

Expanding Square Search (SS)

 Most effective when the location of the search object is known within relatively close limits.
 The commence search point is always the datum position.
 Often appropriate for vessels or small boats to use when searching for persons in the water or
other search objects with little or no leeway.
 Due to the small area involved, this procedure must not be used simultaneously by multiple aircraft
at similar altitudes or by multiple vessels.
 Accurate navigation is required; the first leg is usually oriented directly into the wind to minimize
navigational errors.
 It is difficult for fixed-wing aircraft to fly legs close to datum if S is less than 2 NM.

Sector Search (VS)

 Most effective when the position of the search object is accurately known and the search area is
small.
 Used to search a circular area centered on a datum point.
 Due to the small area involved, this procedure must not be used simultaneously by multiple
aircraft at similar altitudes or by multiple vessels.
 An aircraft and a vessel may be used together to perform independent sector searches of the
same area.
 A suitable marker (for example, a smoke float or a radio beacon) maybe dropped at the datum
position and used as a reference or navigational aid marking the centre of the pattern.
 For aircraft, the search pattern radius is usually between 5 NM and20 NM.
 For vessels, the search pattern radius is usually between 2 NM and5 NM, and each turn is 120°,
normally turned to starboard.

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Track Line Search (TS)

 Normally used when an aircraft or vessel has disappeared without a trace along a known route.
 Often used as initial search effort due to ease of planning and implementation.
 Consists of a rapid and reasonably thorough search along intended route of the distressed craft.
 Search may be along one side of the track line and return in the opposite direction on the other
side (TSR).
 Search may be along the intended track and once on each side, then search facility continues on
its way and does not return (TSN).
 Aircraft are frequently used for TS due to their high speed.

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 Aircraft search height usually 300 m to 600 m (1000 ft to 3000 ft)during daylight or 600 m to 900
m (2000 ft to 3000 ft) at night.

Parallel Sweep Search (PS)

 Used to search a large area when survivor location is uncertain.

 Most effective over water or flat terrain.
 Usually used when a large search area must be divided into sub areas for assignment to
individual search facilities on-scene at the same time.
 The commence search point is in one corner of the sub-area, one-halftrack space inside the
rectangle from each of the two sides forming the corner.
 Search legs are parallel to each other and to the long sides of the subarea.

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Multiple vessels may be used as shown:

 Parallel sweep: for use by two ships.

 Parallel sweep: for use by three ships.
 Parallel sweep: for use by four ships.
 Parallel sweep: for use by five or more ships.

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Restricted Visibility

 A parallel sweep search in restricted visibility poses problems because of the following
considerations:
 Desirability of reducing the interval between SAR facilities as much as possible consistent with
safety
 Resulting loss of search area coverage
 Potential risk of collision.
 During restricted visibility, the OSC should direct a reduction of vessel speed as necessary.
 In such circumstances, any ship not fitted with radar, or whose radar has become defective,
should consider dropping astern of other ships, informing the OSC of its action.
 The ship's search should continue when it judges its position(relative to other searching ships) is
safe to do so
 Iif there is a reduction in visibility and ships have already started to carry out a search pattern, the
OSC may decide that the safest action would be to continue the pattern in force despite the
resulting loss of coverage.
 Should it be necessary for the OSC to consider initiating any of the patterns during conditions of
restricted visibility, the following factors should be considered:
 ships will be proceeding at a reduced speed and searches will take longer
 to search the area thoroughly in such conditions must mean reduction in track spacing• reduction
in track spacing would require a reduction in the interval between SAR facilities and, thus, the
carrying out of more sweeps.
 The OSC may decide to accept a reduction in the area searched and should have regard to the
direction and rate of estimated drift in deciding whether to accept a reduction in one or both of the
length and width of the search area.
 If visibility improves, the OSC should initiate such actions as will best make good the lost coverage
which has taken place.

Radar Search

 When several assisting ships are available, a radar search may be effective, especially when the
position of the incident is not known reliably and SAR aircraft may not be available.
 No prescribed pattern has been provided for this contingency.
 The OSC should normally direct ships to proceed in "loose line abreast", maintaining a track
spacing between ships of the expected detection range multiplied by 1 1/2.
 The table below serves as a guide for detection ranges for ship radar.

Land Search Patterns

 Aircraft search over land differs from maritime searching in that it is usually more difficult to locate
search objects.
 Repeated aircraft searches of an area are often necessary.
 Search of large areas by ground facilities alone is usually not practical but may be effective for
close examination of a small area.

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Visual Ground Search

 Use obvious natural or artificial landmarks such as rivers or roads to delimit search sub-areas.
 Land search facilities should be equipped with large-scale topographical maps with search areas
marked on them.
 Land search facility patterns are normally parallel sweeps or contour searches using a line-abreast
formation.
 Track spacing for lost persons is normally between five and eight metres.
 Search progress should be slow through wooded areas. One square kilometer of woods can be
searched by 20 to 25 persons in about1.5 hours.
 The parallel sweep search:
 Team leader, two flankers on end of each line, and as many searchers as the terrain will allow
 Search line is first formed along the search area boundary
 If an obstacle or an item of interest is encountered, the team stop sand waits for results of the
investigation before the entire search line moves forward again
 Boundary control of each successive sweep through an area is assigned to the pivoting flanker
 Track spacing between each searcher is determined by the distance a person can effectively
search while keeping adjacent searchers in visual and audible contact
 On first leg of search, one flanker will follow a natural boundary or predetermined compass course
while the other flanker marks at rail at the other end to follow after the pivot is made
 If contact is lost with a searcher, the team leader must be notified and the search line stopped until
complete team contact is reestablished.
 The contour search:
 Used when mountainous features can be circled completely
 Pattern is a modified parallel sweep
 Search begins with one flanker at the highest level and the other flanker at the low end of the line
 When the mountain is circled once, the search line is re-formed on the lower side of the bottom
flanker
 General procedures for a parallel sweep search are followed.

SAR Briefing, Debriefing, and Tasking

 The SMC or OSC should provide information to SAR facilities on relevant details of the distress
and all instructions prior to the conduct of SAR operations. Parent agencies may provide this
information by briefing their facilities prior to deployment. Debriefings of the SAR facilities provide
valuable information on effectiveness of the search and can influence planning of the next search.
SAR facilities and the OSC should be aware of the type of information that the SMC is likely to
request. Appendix E provides a sample SAR Briefing and Debriefing Form.
 Masters and pilots-in-command of SAR facilities not designated as search and rescue units should
also be contacted by the SMC or OSC for debriefing.

Further Action on Completion of Initial Phase

 The OSC will normally consider the initial phase to have been completed when, in the absence of
further information, searching ships have completed one search of the most probable area.
 If at that stage nothing has been located, it will be necessary for the OSC to consider the most
effective method of continuing the search.
 Failure to locate the search object may be due to one or more of the following causes:

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 Errors in position owing to navigational inaccuracies or in accuracy in the distress communications

reporting the position. This is especially likely to apply if the position of datum was based on an
estimated position using incomplete information
 An error in drift estimation
 Failure to sight the search object during the search although it was in the search area. This is most
likely to occur if the search object is a small craft, a survival craft, or survivors in the water
 The craft having sunk without a trace. Other than the case of as mall ship or craft in rough
weather, experience has shown that there are usually some traces, even if only debris or oil
patches.

Navigational Inaccuracies of Searching Ships

 This is most likely to apply when navigational fixes cannot be obtained. In this situation, the OSC
may:
 Re-search the same area, allowing for added drift during the time elapsed since calculating last
datum;
 Expand the most probable area, after allowing for added drift, and search the expanded area; or
 Expand the area more in one direction than another, depending on circumstance and information
available.
 Determine a new probable area based upon any additional information received.
 Where information is received to indicate that the original datum was grossly inaccurate,
determining an entirely new probable area would be advisable.
 A small search object, which is easily missed in the daytime, may become visible at night if it
shows lights, flares, or other pyrotechnics.
 The OSC should, therefore, consider using surface craft at night to research areas covered by
day.
 It is good practice when searching for survivors in small craft, in survival craft, or in the water, to
stop the engines occasionally at night and in restricted visibility by day to listen for cries for help.

Evidence of Distressed Craft Found

 In some cases, the search may provide evidence of the distressed craft without survivors being
found.
 This evidence may provide information for a recalculation of datum and revision of the search
area.
 A low-lying, half-sunken loaded ship or aircraft may drift more slowly than a floating survival craft,
even if a drogue is used.
 A derelict may drift at a considerable angle off the prevailing wind direction.
 When wreckage is located it usually consists of debris, possibly with an oil slick.
 Should this have come from the distressed craft, survival craft will usually be found downwind from
the debris
 In some cases, however, a ship may have been abandoned sometime before sinking, in which
case survival craft may be upwind.
 If it is known, or suspected, that survivors are in the water, the area into which they may have
been forced by the buffeting of the seas should also be checked.

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Maneuvering Instructions

 International Regulations for Preventing Collisions at Sea continue to apply fully while carrying out
searches.
 Maneuvering and warning signals will be of particular importance in the circumstances.
 The master of any ship taking part in a search should endeavor to carry out all directions received
and have due regard for the safety of the ship and crew.
 To initiate and conduct co-ordinated search patterns, the OSC should transmit a limited number of
maneuvering instructions by the most appropriate means, and in plain language when practicable.
 The text of the message for the initiation of a pattern and subsequent messages relating to its
conduct or adjustment should be in standard form. The International Code of Signals may serve
this purpose.

Conclusion of Search

 Search Unsuccessful
 The OSC should continue the search until all reasonable hope of rescuing survivors has passed.
 The OSC may need to decide whether to terminate an unsuccessful search (do in consultation
with the SMC when practicable). For this determination, factors to consider include the following:
 Probability that survivors, if alive, were in the search area
 Probability of detection of the search object, if it were in the areas searched
 Time remaining that search facilities can remain on-scene
 Probability that survivors might still be alive.
 The following diagrams illustrate the probability of survival under various temperature, wind, and
sea conditions:

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 The OSC, after consultation with other assisting craft and land-based authorities, should take
the following action:
Ocean Incident
 terminate active search
 Advise assisting craft to proceed on passage and inform the land based authority send a
message to all ships in the area asking them to continue to keep a look-out
 Consult with land-based authorities about the termination of search.

Search Successful

 Once the distressed craft or survivors have been sighted, the OSC should assess the best method
for the rescue and direct the most suitably equipped craft to the scene. See Section 2, Rescue
Function, for discussion on rescue by various types of SAR facilities.
 Ensure that all survivors are accounted for.
 Survivors should be questioned concerning:
 The ship or aircraft in distress, number of persons on board

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 Whether other survivors or survival craft have been seen

 This information should be promptly relayed to the SMC.
 When all rescuing action has been effected, the OSC should immediately inform all search
facilities that the search has been terminated.
 The OSC should inform the SMC of the conclusion of the search and give the following details:
 Names and destinations of ships with survivors, and identities and numbers of survivors in each
 Physical condition of survivors
 Whether medical aid is needed
 The state of the distressed craft and whether it is a hazard to navigation.

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Radar-ARPA
Navigation
Simulator
(Version 1.0)

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(OPERATION MANUAL)

INTRODUCTION

This document describes the functions, main software modules, hardware and supporting tools covered
by ELAB-NAV E Radar Arpa Navigation Simulator.

DEFINITIONS AND ACRONYMS

The definitions for all the acronyms and terms given unique to this document are explained below:

Term Description

N-up North up

H-up Head up

C-up Course up

TM True Motion

RM Relative Motion

EBL Electronic Bearing Line

VRM Variable Range Marker

ENC Electronic Nautical Chart

ETD Estimated Time Departure

ETA Estimated Time Arrival

RNCs Raster Nautical Chart

XTE Cross Track Error

ARPA Automatic Radar Plotting Aid

AIS Automatic Identification System

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OPERATION MANUAL

1. SIMULATOR OPERATIONS

1.1. DESIGN

The ELAB NAV-E RADAR-ARPA NAVIGATION SIMULATOR Instructor Station

Software is installed in one system and the ELAB NAV-E RADAR-ARPA NAVIGATION SIMULATOR Student
Station software’s are installed in 5 student stations each consisting of 2 systems. All these systems are
interconnected via a Network Switch.

The main software modules installed per hardware unit is stated below.

ELAB NAV-E RADAR-ARPA NAVIGATION SIMULATOR Instructor Station

 Navigation Simulator - Instructor module(S/W)

ELAB NAV-E RADAR-ARPA NAVIGATION SIMULATOR Student Station

 RADAR-ARPA
 Navigation Simulator Radar-ARPA module(S/W)
 VISUALS/CONNING
 Navigation Simulator Visuals module(S/W)
 ELECTRONIC CHART SYSTEM(ECS)
 Navigation Simulator – ECS module(S/W)

1.2. PROCEDURE FOR STARTING THE ELAB NAV-E RADAR-ARPA NAVIGATION

SIMULATORSYSTEM

 Switch on the UPS of all the 11 Systems

 Switch on/Boot-up all the computer systems

 Instructor station

 Student Station – 1 (ARPA -1 and Visuals-1)

 Student Station – 2 (ARPA - 2 and Visuals-2)

 Student Station – 3 (ARPA - 3 and Visuals-3)

 Student Station – 4 (ARPA - 4 and Visuals-4)

 Student Station – 5 (ARPA - 5 and Visuals-5)

 Student Station – 6 (ARPA - 6 and Visuals-6)

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 In the Instructor Station,

 Start the ELAB Navigation Simulator Instructor program (Double- click
on “Instructor Console” icon on the desktop)

 Open the Navigational Scenario window and create the exercise.

 Open the Instructor Interrupts window for execution of the exercise.

 Before executing the Simulator exercise, make sure that the following actions are done at the
STUDENTSTATIONS

The RADAR/ARPA, ECS and Visual Displays should have the SHIP Icon on their Status Bars (at the bottom
right of the desktops

 The ARPA, ECS and Visuals modules of the student station is executed from the Instructor
interrupts window of the Navigation Simulator Instructor module

 Once the above actions are taken, then the station is ready for Execution of the Simulator
exercise.

 Now on the Instructor Station, from the Instructor Interrupts window of the ELAB Navigation
Simulator Instructor module, execute the exercise.

 Please refer to the following Chapter “The Instructor Station” for information on procedures
for:
 Preparing an Exercise
 Creating an Exercise
 Saving an Exercise
 Opening a Saved Exercise
 Prior to Executing the Exercise
 Starting the Exercise

2. THE RADAR-ARPA NAVIGATION SIMULATOR INSTRUCTOR

STATION

2.1. General

The Instructor Station is designed for exercise development, execution and monitoring. The Instructor Station
consists of the following three Menu options:

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 Navigational Scenario – This menu is used for

 Creating and Saving an Exercise

 Chart area selection,
 Placement of Own-ship stations, Target ships, Buoys and Racons on the Chart area
 Changing Environment settings (Wind / Current direction and speeds)
 Creating AIS target database and linking
 Enabling Radar Overlay

 Instructor Interrupts – This menu is used for

 Execution of Exercise
 Changing Weather Conditions (Rain, Fog and Cloud cover)
 Invoking equipment failures and errors

 Student Ship Data – This menu displays the present position of all the Own- Ship Stations
(Latitude& Longitude) along with their Courses and Speeds.

2.2. INSTRUCTOR CONSOLE WINDOW

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This is the Main panel seen on the Instructor console. (See the picture above). The system scenario can be
chosen from this window. There are 3 Menu options available for the Instructor as displayed below:

(1) Navigational Scenario

(2) Instructor Interrupts

(3) Student Ship data

Brief descriptions of each of these menu-options are given below:

2.3. Navigational Scenario

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The Instructor station’s Navigation Scenario enables the instructor to perform the
following tasks:

 Create program and restore exercise in accordance with training objectives

 Select the data base/exercise area.
 Select a pre-programmed exercise.
 Manually change exercise parameters if necessary.
 Select the hydrodynamic models for Own Ships and change their parameters, such as speed or
heading.
 Change the parameters of Target Ships and their type.
 Specify environmental conditions.

2.3.1. Creating an Exercise

 First Click on “REMOVE ALL TARGETS ” and then“APPLY”

 Click on the Chart-Area pull-down menu to display list of available charts and select the required
chart area. Once the chart gets loaded on the “Chart-Window” of the screen. Then click
on“APPLY”.

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 Click on “OWN SHIP” button and then click on the chart area where you want the Own ship to
appear. A Ship Entry dialog box will appear in which the following information can be input:

 Ship Station ID (i.e, Station 1,2,3 or4)

 Ship Type (Cargo, Container, Bulk, OBO or Tanker)

 Ship’s Course (speed cannot be input) Click “OK” and then “APPLY”.

 Similarly “Target Ships” can also be placed on the chart area, giving their Type, Course and
Speed. When clicked on the chart area, a window appears, where the following can be selected:

 Select Target Ship type (You can choose from 5 types of Target ships)
 In the Course Edit field, key-in the required course.
 In the Speed Edit field, key-in the required speed.
 Click “OK”.
 The window will disappear.
 To activate this target, click “APPLY”.

 Buoys, RACONs and SARTs can also be placed if required.“APPLY”

 “ENVIRONMENT Settings can be used to select the following:

 Wind Direction &Speed
 Current Direction &Speed
 Night Navigation, if required (for DAY Navigation, do not tick this option)

Click “OK” and then “APPLY”.

2.3.2. Saving An Exercise

 After having placed all the required targets, own-ships and

Environment conditions, click “APPLY”

 On the Exercise field, Type the required FILENAME and

 Click “APPLY”.

 Now Click on the “File” button. A dialog box will open, on

which the “SAVE” button is to be clicked.

The exercise thus created would be saved only for the

particular CHART AREA selected.

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2.3.3. Opening A Saved Exercise

 First Click on “REMOVE ALL” and then “APPLY”

 Select the relevant Chart area.“APPLY”
 Click on “File”.
 Now the Instructor opens the Exercise pull-down menu. Pre-set exercises for the selected Chart gets
displayed. Instructor can select one of those exercises. Click on “OPEN”. Then “APPLY”

 On selection of the preset exercise, the own-ship, moving targets, Buoys, Racons & SARTS appear
at specified positions on the “Chart-display”, each appearing in different colors as indicated by the
legend area on-screen. The positions of all targets are displayed on the data-grid at the top half of the
screen.

 Even on the pre-set exercise, the Instructor can make modifications by adding or deleting one or
more targets or by re-positioning the own-ship.

 To delete a preset target or own ship, click on the required target or own ship on the data grid. The
selected target will be marked by a RED circle around it. Now use the DELETE button on the
keyboard to delete the own- ship or target.

 In case the Instructor makes any changes to the preset scenario, he can save the new scenario. The
Instructor may save this as a new exercise or overwrite the previously saved one.

 Finally, the Instructor can click on the “APPLY” button to invoke such changes for conducting of
exercise.

2.3.4. During An Exercise

During an exercise (and “off-line”) the Instructor will be able to:

 Run, edit, restart, save, stop the exercise

 Control Target Ships by manual control. Their Courses and speeds can b changed.
 Add new Target Ships anywhere within the exercise area
 Stop and freeze Target Ships
 Control all environmental conditions manually
 Control external equipment and facilities
 Control input of failures and errors

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2.3.4.1. Changing Target’s Course and Speed during an exercise

The positions of all targets, their types, courses and speeds are displayed on the data-grid at the top half
of the “Navigation Scenario” screen.

 Single-clicking on the target in the data-grid will highlight that particular target in the chart area
of the Navigation Scenario Screen.
 Double-clicking on the target in the data-grid will open the course & speed edit window of the
target.
 Change the Course or Speed value, as required
 Click “OK”
 The newly edited values will appear in the tabular form.
 Click “SAVE”. The window will disappear.
 To activate the changes made, Click “APPLY” on the Navigation Scenario screen.
 Check for the changes made in the data-grid (top half of the “Navigation Scenario ”screen)

2.3.4.2. Changing Environment Settings during an exercise

 Click on the “Environment Settings” Tab in the
Navigation Scenario Screen.

 Edit/ Change the

 Wind Speed
 Wind Direction
 Current Speed (Drift)and
 Current Direction(Set)
 Click “OK”. The window
 To activate the changes made, Click
“APPLY” on the Navigation Scenario screen.

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2.4. INSTRUCTOR INTERRUPTS

2.4.1. Executing The Exercise

To start / execute an exercise, first close the “Navigation Scenario” Window. Then from the Main
Instructor Screen, select “INTRUCTOR INTERRUPTS”.

The following window opens up:

To start execution of the Simulator software at the Student station,

 Click at the signal picture in the grid (under Ship-1).

 The signal turns yellow and the software gets executed at the ship station.

At the Student station, the Radar display, Visuals-cum-Conning, ECS Screens shows up. Once the
student station is ready for operation, the signal under Ship-1 of the “Instructor Interrupts” screen turns
to green.

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2.4.2. Controlling Radar Equipment facilities

From the “INSTUCTOR INTERRUPTS” Screen, the following Radar facilities can be invoked:
 Spoking effect
 Blind Sector
 Racon
 Ramark
 Side-Lobes
 Multiple-echo
 Performance Monitor Signal
 SART signal
 Rain Clutter (Invoking Rain)
 Sea Clutter.

 Click under the required facility for SHIP-1. The Cross mark will change into a TICK mark
 To activate click “APPLY”

2.4.3. Invoking Failure and Errors

The Instructor Station also allows the instructor to input and monitor information relevant to failures
and errors for the Own Ship.

Bridge Equipment Failures and errors:

 Gyro failure
 Gyro error
 Log failure
 Log error
 Auto pilot failure
 Echo-Sounder failure
 ARPA failure
 GPS failure

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To activate the Failures

 Click under the required Failure column forShip-1.

 The Cross symbol will change into a Tick Mark.
 To activate, click on “APPLY”

To de-activate the failures,

 Click on the Tick mark symbol. It will change into a Cross symbol.
 Click “APPLY

2.4.4 Changing Weather Conditions

Instructor can change the weather conditions by introducing Rain, Fog (with variable visibility
ranges) and Cloud cover (medium & overcast)

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2.4.5 Ending an Exercise

There are two ways of ending the Simulator exercise.

 From the Radar/ARPA Simulator Module

 Click on the POWER button located at the bottom-right side of the Radar/ARPA
simulator screen. This will close all the simulator screens (Radar/ARPA, Visuals /
Conning) of the student station.

 From the Instructor Station

To Stop / End an exercise, first close the “Navigation Scenario” Window, if open. Then from the Main
Instructor Screen, select “INTRUCTORINTERRUPTS”.

 Click at the signal picture in the grid (underShip-1).

 When asked for confirmation to stop, click YES.
The signal will turn RED and all the simulator screens (Radar/ARPA, Conning, ECS
and 3 Visuals) of the student station will close

3. THE NAVIGATION SIMULATOR STUDENT STATION

3.1. RADAR and ARPA Simulator

3.1.1. INTRODUCTION

The Radar/ARPA module consists of a table-mounted, single Monitor display (combined Radar and
ARPA) with simulation software capable of producing realistic Radar/ARPA operation and presentation
for the training of collision avoidance and Radar navigation.

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This simulator incorporates the generic features of ARPA. It simulates the common ARPA features like

 Automatic & Manual Acquisition

 Tracking, Alarms
 Guard Zone
 Trial Manoeuvres
 Vector, Trials, History Etc

3.1.2 CONTROLS & DISPLAY

All operational controls and displays are located on the front panel of the Radar/ARPA unit. There is a
separate display box showing the own ship heading and speed, range scale selected, range rings, VRMs &
EBL on/off status, cursor position, head up or north up mode, true motion or relative motion.

POWER

To switch ON and switch OFF the Simulator

RANGE SCALES

The Student can increase or decrease the Range scale by

clicking the right and left arrow buttons under “RANGE” on the
panel. The range scale varies from 0.75 nm, 1.5, 3, 6, 12, 24 &
48 nm. All objects on

RANGE RINGS

The Student can switch on and switch off the range rings by
clicking on this button on the panel. There is a separate switch
for controlling the brilliance of the fixed range rings. Three
Rings are visible on Range below 3 NM and 6 Rings are visible
above 3 NM range

EBL ON/OFF

There are two EBL’s available in the simulator. The Student

can display or hide both of them by clicking on these buttons on
the panel and select “ON” from the drop-down menu. The
indication on the Top-left part of the button color changes to red
when the EBL is “ON” .the PPI get adjusted accordingly. After
putting the EBL “ON”, the Student can move the EBL in both
clockwise and anti-clockwise directions by pressing the left-
arrow and right-arrow- buttons respectively. The direction of the
EBL ie the bearing is displayed on the left bottom corner of the
PPI, and denotes whether the bearing is “True” or “Relative”.

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EBL OFFSET / RESET

The EBL can be offset from the centre and placed anywhere on the screen. To do this, click on the EBL
button and select “Off Centre” from the drop-down menu and then click anywhere on screen. It can be
increased or decreased in length as needed by left-clicking the mouse on the extended line or on the
line, as the case may be. By selecting “Reset” from the drop-down menu, the off- centered EBL
returns to the PPI centre point.

VRM ON/OFF

The Student can display or hide the Variable Range Marker by clicking on this button on the panel.
The button color changes to red when the VRM is at “ON” or in visible state.

After putting the VRM “ON”, the Student can increase or decrease the VRM by pressing the left-
arrow-button or right-arrow-button respectively. The range is displayed on the left bottom corner of
the PPI in NM. The VRM can be changed to off-centered mode also.

VRM OFFSET / RESET

The VRM can be offset from the centre and placed anywhere on the screen. To do this, click on the
VRM button and select “Off Centre” from the drop-down menu and then click anywhere on screen.
By selecting “Reset” from the drop- down menu, the off- centered VRM returns to the PPI centre
point.

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Head-up, North-up & Course-up Modes

The Student can change the mode by clicking any of these buttons. By default, the radar is in North-
up position, unless the student changes the Default Setup.

Anti Clutter switches for Sea and Rain

While the exercise is in progress, the Instructor can invoke “Rain” or “Sea” effect on the Student
console and the student is required to use the Anti- clutter controls to filter out the disturbance. By
left-button-depression, the anti-clutter switch increases and removes the effect and by right-button-
depression it gradually restores the effect. If the Anti-clutter control is increased too much, then the
actual targets would also disappear from the PPI.

Heading Marker

The Student can hide the heading marker temporarily by depressing the “HDG Marker button”, to
see if there

ACQUIRE (Target Acquisition)

(Left Click for Acquisition and Right Click for Cancellation)

Clicking on the Acquire button activates the ARPA acquisition mode. Every target when acquired is
enumerated and enclosed within either a rectangular or a circular symbol. The average acquisition
time is 90 seconds. Any number of targets can be acquired at any point of time.

A tracked target status display provides data on operator selected target. This data presents target
number, range, bearing, CPA & TCPA in hours, minutes & seconds and the target’s course & speed.

This simulator is capable of tracking

more than 20 targets and it can
simultaneously display and update
the information. The ARPA clearly
indicates the acquired targets with
relevant symbols.

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VECTOR

The student is allowed to enter his choice and designate all vectors as true or relative and the time
duration, setting the length of the vectors.

HISTORY

The student can view the history of each target for the specified history time .

TRAILS
ll targets can be made to show the trails of its past position in both head-up and north-up modes.

GUARD RINGS
The student is able to set the start and end of each guard ring, and turn it off when desired. Any target
that crosses the guard rings activates the intruder alarm if auto acquire is put on. To set the start of
guard zone, left click on the required position on the screen. To set the end of guard zone, right click on
the required position

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EXCLUSION ZONE

The system allows the construction of

exclusion area to keep the targets from
being automatically acquired in that
region. The area is constructed by
giving two left clicks followed by a right
click on the radar PPI.

TRIAL MANOEUVRE

This is provided for the student to evaluate the effect of change in course and/or speed of own
ship on all the targets before the own ship actually performs the manoeuvres. During the trial
manoeuvre a warning display appears on the screen, reminding the user that he is in trial
manoeuvre mode.

Parallel INDEX

This can be switched on by the PI On/Off switch and rotated clockwise or anti- clockwise by the
right-arrow and left-arrow controls respectively.

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PULSE

Clicking on the Pulse switch can change the length from short too long or vice versa. The PPI blinks
for a few seconds and then comes alive with the new pulse read-out at top-left of the PPI.

Standby Mode

A standby control is provided that allows the operator to switch the system from a simulated ‘Standby’
mode to the “ON” mode of operation.

ALARMS

Following audio/visual alarms are sounded under the specified conditions:

 CPA alarms when any acquired target is calculated to pass by less than the CPA limit set by
the user.
 TCPA alarms when any acquired target’s time to CPA is less than the operator-set-TCPA
limit. The target that causes the alarm is indicated by a flashing symbol.
 The intruder alarm occurs whenever a guard ring has been turned on with the auto
acquisition.

MUTE

This control mutes the various audio alarms.

SETTINGS

Before switching on the ‘Power’ student can set various parameters as required

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TRUE MOTION

To enter into True motion mode the student has to click the ‘True/Rel’ button. A pop-up menu appears,
prompting the user to enter sea stabilized or land stabilized mode.

Selecting “Sea-Stabilized” will change the display to TM-sea stabilized immediately.

On selecting “Ground-Stabilized”, a fixed (stationary) target echo has to be acquired. Only then the
display will change to TM-Ground stabilized. The acquired fixed target is marked as “echo reference
point” on the screen.

In true motion display, stationary targets do not move, and own ship and targets move on their true
course and speed. Own ship position can be started from any point (not more than 75% of the display
radius). The system automatically jumps the display with own ship repositioned back to the start point.

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MAPPING

The ARPA simulator provides exclusive features of video mapping simulated and displayed in the
most realistic manner. This facility allows the user to draw different types of lines, insert different
shapes for marking the navigational buoys, waypoints and anchoring points. The entire map can be
saved onto the hard disk and recalled whenever needed. The student can click the map and drag the
mouse and align it with the real picture on the PPI and un-click again to reposition the map at the
required position.

Before drawing the Map on the PPI, make sure that the display is on RELATIVE MOTION –
NORTHUP.

To draw the TSS lines on the screen, first select a reference point (Tip of Land or Racon) on the chart,
close to the TSS. Take range and bearings of all the TSS points from the selected reference point on
the chart. After having noted all the range and bearings, click on the Map button on the Arpa panel.

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On clicking the Map button on the ARPA panel, the “Map Control” window pops-up. It has following
buttons:

 Symbol – While drawing the Map, the student can create various scenarios, by placing the
symbols from the pop-up palette on the Map drawing. Anchor points, waypoint, buoys, etc can
be placed and constructed as part of the Map. For example, the student may select a port
hand buoy and insert it on the port side of the channel drawn on the PPI by clicking at the
desired point of insertion. He can then select from different types of cardinal buoys to insert
them in the map. Furthermore he can mark waypoints and anchoring points on the map in
order to plan his passage.

 Select a symbol and place it on the centre of the screen. This symbol represents the selected
reference point. With the help of VRM and EBL mark all the TSS points with various other
symbols. Now use the “Start Line” and “Stop Line” buttons to draw lines joining all the marked
points.

 Start line and Stop line – By clicking the Start line, the student can specify the starting
point for drawing the channel on the PPI. On clicking any other point on the PPI, after
selecting the Stop line button, the software assumes that as the end-point and draws a line
connecting the two points. This way, he can draw any number of contoured paths and define a
channel. The thickness of the line can also be changed by selecting the required line-type as
displayed in the lower part of the pop-up menu before clicking on the “start line “icon

 Load & Save buttons – After creating a Map, the student can save it by specifying any
name to that Map, so that at a later stage whenever required, he can recall that Map. Clicking
the “Load” button and specifying the filename will display the map on the PPI.

 Position – The student can reposition the Map anywhere on the PPI, by left clicking on the
symbol (reference point) and without leaving the click dragging the mouse and placing (un-
clicking) it on the real echo of the reference point. The map will now shift and get aligned with
the actual echo.

When the Position button is clicked, the button turns red. After re- positioning the map, again click on
the Position button and note that the buttons turns Black. This is necessary for the shifted symbol to be
continuously attached to the real echo.

PPC

The PPC [Potential point of collision] can be easily calculated and displayed visually on the PPI on our
Radar/ARPA Simulator. In order to calculate the PPC of any targets, just click on the targets and
acquire them. Once acquired press keystroke “P” or click on the PPC button on the panel.

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The computer calculates the PPC and

the course to steer for each acquired
target and displays it continuously on
the PPI. This can be of immense use in
ascertaining as to which course should
be avoided in order to avoid direct
collision with the concerned target. Or
conversely, which course to follow in
order to home directly for a target, for
example a SART placed on a lifeboat, in
distress.

The PPC is shown in the North-up mode

and would prompt the student to switch the
mode, if not already in North-up position.
It not only draws the PPC point but also
specifies the course at which the collision
will take place. There is a possibility that more than one PPC points could appear for an acquired target

PAD

The PAD [Predicted area of danger] is constructed on the PPI for all acquired targets on pressing
keystroke ‘X’ of the keyboard or clicking the PAD button on the panel. The software also allows students
to specify “Miss Distance” for acquired target.

In a heavy traffic, it’s not enough just to know the

PPC and the collision course of each target as
seen on the PPI. It is more practical to have
knowledge of the area {surrounding the target} that
should be avoided in order to avoid a close quarter
situation. User enters a safe distance, which he
intends to pass off from the concerned target either
off his bow or his stern. The computer then draws a
polygon with or without the PPC at its center and
depicts continuously the predicted area of danger,
which should be avoided in order to avoid
passing off at a distance lesser than the “miss
distance” (CPA) as desired by him. The shape and
position of the PAD for each target keeps changing
depending upon the relative position of the target
and the own ship and their relative speeds. Care
should be taken that the heading marker of own
ship does not enter the PAD displayed on the PPI
for any target.

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PERFORMANCE MONITOR

This facility has to be activated from the Instructor station. To see the PM signal, the Range Scale should
be changed to 1.5 Nm

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3.2 VISUALS-cum-CONNING SIMULATOR

It gives a complete view of the horizon as seen from the bridge while steering different types of
vessels. Currently, the simulator offers a choice of 5 different ships, viz. General Cargo, Container,
Tanker, OBO and Bulk Carrier.

Steering can be done both in day and night times and in both Open Sea and Restricted waters. The
Bridge Team gets the feel of real-life sailing at sea in each of the scenarios.

Additionally, the instructor can introduce current and wind effects in moderate to poor visibility to
make the exercise more interesting and challenging.

The Simulator provides for a complete 360 degrees view from the bridge. The Operator can change
the angle of view from the Conning display. It also provides the Binocular view of the entire 360
degrees.

Instructor can invoke environmental conditions like wind, current, fog and Rain (for restricted
visibility) from the Instructor station

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To summarize, the various scenarios and effects covered by the Simulator are:

 Open Sea or Restricted Waters

 Day time or Night time Navigation
 Wind effect
 Current effect
 Fog effect
 Rain Effect
 Cloud Cover
 Full 360 degree view by toggling the view angle
 Binocular view of complete 360 degree scenario
 10)Sound effects – Own-ship Oncoming ships, Engine, Water waves, etc

3.2.1 OWN SHIP DATA

3.2.2 CONNING PANEL

The Conning Panel is situated at the bottom of the Visuals Screen. The following panels are
available for use:

 GPS-1
 GPS-2
 AUTOPILOT
 DEPTHINDICATOR
 RUDDER
 TELEGRAPH
 VIEW-ANGLE
 COURSERECORDER
 VISUAL BEARING /BINOCULARS

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3.2.3 GPS-1 &GPS-2

Both the GPS panels are similar.

They display the following information:

 Latitude
 Longitude
 CMG
 SMG
 Date
 Time

ROUTE-DETAILS

This part of the GPS Panel displays the edited and saved routes The listed routes can be selected and

ACTIVATE – for activating the selected route. Activation of the route is required for the Auto-pilot to run
on COG Control and AUTO-TRACK Control.

EDIT – for editing the selected route

ADD NEW - for editing a new route

Once all the way-points are fed in, clicks SAVE

For re-editing a particular way-point, select it and click EDIT for deleting a particular way-point, select it
and click DEL

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3.2.4 AUTO-PILOT

First the student needs to steady on a particular course. Then Click on the Autopilot tab of the bottom
panel

Having done that, the Auto-Pilot Panel appears

By default the Autopilot is on Manual steering, indicated by a green light below MAN.

HDG Control

When clicked, the present Gyro course appears on the SET COURSE window

 Click on SET , the gyro course with be shown between parenthesis[030]

 Now the Autopilot is active on HDG Control.
 To change the course while on Autopilot, click on the PREV and NEXT buttons to increase/
decrease the course value
 Again Click on SET, to execute the new course.

As far as the response of the Auto-pilot is concerned, intermittent malfunction has been incorporated in the
software with the intention that the Student should notice it and immediately change over to MANUAL
steering, by click on MAN.

COG Control

For this, we require to have already activated a route on the GPS-1 panel. If route is not activated, the
moment COG Control is clicked; it will prompt to activate the route.

Once on COG Control, the Autopilot will steer to make the COG equal to the CTS of the present Leg of the
route.

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AUTO-TRACK Control

For this, we require to have already activated a route on the GPS-1 panel. If route is not activated, the
moment AUTO-TRACK Control is clicked; it will prompt to activate the route.

Once on AUTO-TRACK Control, the Autopilot will check the Cross-track error of the vessel wrt the present leg
of the route. If the vessel is off-track, the autopilot will steer to bring the vessel back on track. Once the vessel
is on track, the autopilot will maintain the vessel on track.

Once the vessel reaches the wheel-over point of the present leg, the autopilot alters the course after giving an
alarm indication.

During the alteration the auto-track is not active.

After having steadied on the new course, the auto-track becomes active and does the needful.

3.2.5 DEPTH

This panel displays the UKC of the vessel in meters.

It also consists of

WHISTLE CONTROL –
FOG SIGNAL PANEL

Two type of Fog Signals can be sounded from here.

Manual – To blow whistle once per click. (One Long Blast

and One Short Blast)
Auto– To blow whistle at a certain interval continuously.
The following Fog signals are available on Auto mode :.

 One Prolonged Blast

Fog signal of a power driven Vessel making way
through water.

 Two Prolonged Blast

Fog signal of a power driven Vessel Underway but not making way through water.

 One Prolonged Blast followed by Two Short Blasts

Fog signal of Vessel Not Under Command (NUC), vessel Restricted in Ability to Manoeuvre
(RAM), & vessel Constrained By Draught (CBD)

 One Short Blast Followed by One Prolonged Blast and a Short Blast
Fog signal of Vessel at Anchor or Vessel Aground

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3.2.6 VISUALBEARING

Switching on this facility enables the operator to take Visual Bearings of objects on the Visuals Main Screen.
The right and left arrow keys are used to move the picture accordingly. For taking bearings, the vertical
Centre-line needs to be placed on the object. The Bearing reading is displayed onscreen.

3.2.7 BINOCULARS

When this facility is switched on, a binocular view will appear on the Main Visuals Screen. The “Zoom+” and
“Zoom-” buttons can be used to zoom in and out of the picture. The right and left arrow keys can be used to
move the binocular view towards starboard or portside.

3.2.8 SHIP INFO

Clicking on this button will show the Own Ship’s Particulars on the Main Visual Screen (Top Left portion). The
following details will be given

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3.2.9 PANNING VIEW (360deg)

This facility is used to view the full sea area around the ship (360 deg) divided into 8 views:

 Right ahead
 Starboard Bow
 Starboard Beam
 Starboard Quarter
 Right Astern
 Port Quarter
 Port Beam
 Port Bow

Selecting any one view from above shows that area on the Main Visual screen and the other visual screens
change accordingly.

3.1.10 TELEGRAPH

This control is used to give Engine movements, to control the speed of Own ship.

Click on the UP arrow and DOWN Arrow for increasing/ decreasing speed.

The various Telegraph positions are:

 Sea Speed
 Full Ahead
 Half Ahead
 Slow Ahead
 Dead Slow Ahead
 Stand-by
 STOP
 FWE
 Dead Slow Astern
 Slow Astern
 Half Astern
 Full Astern

3.2.11 RUDDER

Every Click on the RIGHT arrow or LEFT arrow, will move the Rudder angle indicator (located on the top
portion of the main visuals screen) to Starboard or Port by 5 degrees

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3.2.12 GYROCOMPASS

(Top Right Side Of The Main Visuals Screen)

The pointer of the Gyro Compass shows the ship’s Course being steered. The student on the steering wheel
can steer the vessel using the Gyro Compass reading. Apart from this, a digital read-out of the Gyro Compass
course is also displayed on the Over-Head Panel.

3.2.13 COURSERECORDER

This panel records the Gyro course and displays it a a graph (Course vs Time)

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3.3 ELECTRONIC CHART SYSTEM (ECS)

3.3.1 Introduction

The ECS display has seamless integration with the Visual Steering Simulator, Control and Conning
Station, and the stand alone Radar / ARPA simulator to form the total Bridge Team Management

simulator.

CONTROLS & DISPLAY

The tool bar above the main display panel includes some common operations to work with Electronic
Navigation Display unit. There is a status bar that continuously shows the position of the mouse cursor in
Latitude & Longitude. It also gives some attributes of the various navigational marks drawn on the main
display.

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The color settings of all the objects in the screen and the size of the targets as well as own ship could be
adjusted according to users choice by editing a preset file (Ecnsis.ini) available in application home directory

ZOOM

The display could be scaled by operating ‘Zoom (+)’ and ‘Zoom (-)’ buttons. The scaling could be done to any
level on users demand.

MOVE

User may view a select area of the display using this feature. When he clicks the ‘Move’ button the mouse
cursor takes shape of a hand. Now he can move the chart to view the desired region

SHAPES

By clicking this button, user gets the tool window to draw the navigational marks

Separate buttons are provided for drawing objects like lines, rectangles, circles, arcs, etc. The color, fill-mode
and transparency level could be adjusted according to the user’s choice

SELECT
The ‘Select’ button is used to select a particular object drawn on display area. Whenever a figure is selected
the attributes like length, bearing, radius, height, width, etc are displayed on the status bar

DELETE

Any object on the display area could be deleted by pressing the ‘Delete’ button. The object has to be first
selected before deletion

HISTORY

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The ‘’History’ button is used to toggle the history mode. When the history is ON, the system gives the true
history for the all targets as well as the own ship.

SAVE SESSION

The whole session can be recorded for debriefing. When the ‘Save Session’ is clicked the Session Save
dialog box pops up. User can specify a session file name and save it on the hard-disk for subsequent
playback

DE-BRIEFING

The recorded session can be replayed for de- briefing. User can go to the tool window for controlling the de-
briefing by clicking the ‘De- Brief’ button.

Using this tool window any recorded session could be loaded for playback & de-briefing. The replay can be
viewed in three different speeds. User can pause and reverse the replay at any point of time, by clicking
appropriate buttons

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SEARCH & RESCUE

The Search and Rescue tool window could be invoked by

clicking the ‘SAR’ button

Here student gives the position of the datum in Latitude-Longitude,

track- spacing and the angle of the orientation of the search pattern
to be drawn. The search pattern can be drawn in six different
modes.

 Square Search
 Sector Search
 Ship Search
 Ship Search
 Ship Search
 Ship Search

To apply the setting for the search pattern to draw, student has to
click the ‘Apply’ button.
Then to draw the figure the ‘Draw’ check box should be ticked ON

SETTINGS

Presetting can be made using the Settings tool window. On

clicking the ‘Settings’ button the tool window appears

Using this tool window, student can opt to display the Chart Title,
Replay Indicator Depth values. He can run the Electronic Navigation
Display in stand-alone mode by disconnecting the ARPA. When the
system is running in stand-alone mode a particular chart can be
viewed by choosing the chart name from the list box. During the
session the display can be viewed in ‘True’ or ‘Relative’ mode with
respect to the position and course of the own ship

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