Arab Academy for Science and Technology and Maritime Transport
COLLEGE OF MARITIME TRANSPORT
Subject: Marine Certificate
SE424
Research Title: Report on The Underwater Survey
Class: 8/7
Name: Mohamed Ehab Ahmed Youssef
ID: 17100854
Captain: Hesham El-Sayad
12th Week Report
Table of Contents
1. Introduction...........................................................................................................................................2
1.1 Definition……………………………………………………………………………………………………………………………………2
2. PRE-EXAMINATION IN-WATER SURVEY PROGRAM.............................................................3
3. IN-WATER SURVEY REQUIREMENTS..........................................................................................4
4. WHAT IS A SHIP SURVEY AT THE REQUEST OF CLASSIFICATION SOCIETIES UNDER
WATER?....................................................................................................................................................5
5. WHICH SITUATIONS IS A SHIP SURVEY CARRIED OUT IN?.................................................6
6. PROCEDURES WHEN UNDERTAKING AN IN-WATER SURVEY……………………………………………………………6
7. Conclusion..............................................................................................................................................9
8. Reference................................................................................................................................................9
1. Introduction
In-water survey (referred to by various classification societies as IWS, BIS, etc.) is
a method of surveying the underwater parts of a ship while it is still afloat instead
of having to dry-dock it for examination of these areas as was conventionally done.
1.1 Definition
The underwater survey is a scheduled or unscheduled inspection, but necessary
due to the certain circumstances, expertise of risks. The underwater survey of the
ship’s hull state is a procedure which is required for each ship irrespectively of her
type and cargo-carrying capacity. The underwater survey is necessary for
estimation of the general and detailed technical state of the ship’s hull underwater
part before docking, purchase or sale of the ship as well as a compulsory part of a
package of measures approved by the Classification societies.
2. PRE-EXAMINATION IN-WATER SURVEY PROGRAM
The first step to make an in-water survey possible is to send an initial application
to the classification societies’ Ship Safety division indicating the intention to have
any ship(s) participate in an in-water survey program.
The ship then must be examined to get an approval of Class Societies Ship Safety
Headquarters to get into the In-Water Survey Program. This examination of the
underwater portion and fittings of the hull as required by the appropriate
regulations can be made by a team of competent divers and technicians in the
presence of a Marine Surveyor. The diving company must be approved by the
appropriate Classification Society in order to execute this survey.
The in-water survey should provide, for as far as possible, the information on the
condition of the vessel’s underwater hull and fittings usually obtained from a
(previous) dry docking survey.
One of the other requirements that needs to be checked are the stern tube seals. The
report needs to provide information ascertaining that the seal assembly on oil
lubricated bearings remains intact and that the clearance or wear down measure of
the stern bearing has been verified to be in accordance with OEM specifications.
For wood or rubber bearings, an opening in the top of the rope guard and a suitable
gauge or wedge should be provided for checking the clearance by the diver.
Please note that in case the Marine Surveyor is not satisfied with the outcome of
this first in-water survey or if the condition of the vessel warrants a survey in dry
dock this must be arranged by the ship owner. Read our blog to find out which
preparations need to be made for in water seal repair.
3. IN-WATER SURVEY REQUIREMENTS
1. Master’s Statement
At the time of an in-water survey the Master or Owner’s representative should
provide a declaration of all suspected or actual damage that has occurred since the
previous dry-docking.
2. Survey Site
The proposed survey site should be in a protected location with calm clear water
providing good underwater visibility. Visibility is typically greater than 2 meters
length. Sufficient visibility shall be available to enable the Marine Surveyor to
ascertain if the hull has undergone any permanent setup or set down. Special
attention should also be given to the effects of current.
3. Hull Condition
The hull should be clean for external survey and the Marine Surveyor should be
satisfied that the method and quality of pictorial presentation is satisfactory and
that the information obtained enables a reliable assessment to be made of the
condition of the hull. The survey should be discontinued if the conditions or
equipment deteriorate to the extent that the transmitted pictures and/or
communications are no longer acceptable.
4. Underwater Areas
An examination of the entire vessel below the waterline should be carried out by a
competent diver using closed circuit television with two-way communication
capable of being monitored by the Marine Surveyor as required.Where practicable
the in-water survey should be carried out while the vessel is in Light Operating
Condition to facilitate the survey.
5. Above Waterline Areas
An examination of the outside of the shell plating above the waterline and exposed
portions of appendages should be carried out by the Marine Surveyor. Means
should be provided to enable the Surveyor to accomplish this visual examination.
6. Internal Inspection
Where a defect or damage is detected or suspected as a result of the in-water
survey or the Master’s statement, the internal structure should be examined as
considered necessary to clarify or confirm the findings. Vessels operating in ice
should have the internal structure examined in way of areas which are susceptible
to ice damage. In this respect, attention should be given to the hazards associated
with entering ship’s tanks.
7. Report
Copies of the diver’s report, pertinent colour photographs and/or video tapes
should be submitted to the attending Marine Surveyor and Ship Safety
Headquarters for record purposes.
4. WHAT IS A SHIP SURVEY AT THE REQUEST OF
CLASSIFICATION SOCIETIES UNDER WATER?
In most cases, the inspection of the vessel is carried out under the supervision of an
inspector of the Classification Society. The diving company must have a
Certificate of recognition from the Classification Society under which the survey
of the vessel is carried out to perform such work.
5. WHICH SITUATIONS IS A SHIP SURVEY CARRIED OUT
IN?
An underwater survey of the vessel is carried out in the following cases:
Necessities for obtaining/renewing a license for the transportation of
passengers, goods or a permit for operation.
Assessment of the condition of the vessel upon its purchase, sale or lease.
Before a scheduled repair.
In cases of an unplanned situation: damage after a collision with other
transport objects, landing on a sandbank or complicated weather conditions.
6. PROCEDURES WHEN UNDERTAKING AN IN-WATER
SURVEY
A meeting should be held before the IWS is to be carried out to coordinate the
various
participants (i.e. owner ‘s superintendent, deck and engineer officers of the ship,
diving and
survey personnel), to review and agree all aspects of the survey and adopt a final
survey
schedule. The responsibilities for the control and supervision of the survey,
including
arrangements for locking the propellers, rudders and thrusters, the stopping of all
pumps
and the provision of effective communication should be clearly assigned. This is
not the role
or responsibility of the surveyor, who is there to witness the results of the survey
and request
examination of particular areas. A Permit to Work system should be used to ensure
the
safety of divers and other personnel. This should include informing relevant ships
staff and
port authorities. However, where the surveyor considers the practice to be unsafe
they
should refuse to take part. The primary aim being to provide safe and effective
conditions
for the divers and a successful survey.
2. The programme agreed for the IWS should ensure that necessary priority is
given to the
examination of the major hull penetrations, shafting, rudder, stabilizers, bow
thrusters, any
suspected contact/damage, etc., in the best available conditions.
3. Ideally the survey should be conducted in a manner permitting the sighting of
the forward
and after ends of the hull towards midship in order that the shape of the hull can be
sighted
against the surrounding water. The amount of hog/sag should be recorded using
draught
marks or loading computer.
4. The survey of large areas of flat of bottom can prove difficult due to light and
sight problems
and advice must be taken from the senior diver as to the best procedure to be
adopted.
5. When actual or suspected contacts have been recorded by the Master, the
surveyor should
make an internal examination of the hull, if access is possible, either immediately
before or
after the IWS. In this respect attention must be given to the hazards associated with
entering
ship’s tanks.
6. The survey should not be commenced unless the surveyor is satisfied with the
visibility,
scale effects due to using closed circuit TV and detail provided by the underwater
cameras
on site. The survey must be discontinued if the conditions or equipment deteriorate
to the
extent that the transmitted pictures and/or communications are no longer
acceptable.
7. Visibility and scale checks should be undertaken at intervals during the survey.
Visibility
must be to the surveyor’s satisfaction, but if generally below 5 metres surveys
should be
discontinued.
8. It is essential that the entire hull and associated fittings are surveyed in order to
accept the
IWS in lieu of an inspection in dry dock.
9. The out-of-water portion of the hull should be surveyed in conjunction with the
IWS.
10. Caution should be taken not to underestimate defects observed externally
during IWS.
Where a defect/damage is detected or suspected as a result of the IWS, the internal
structure should be examined as considered necessary and practical to clarify or
confirm
the findings. This examination will provide a basis for a decision regarding the
need for
either a temporary repair afloat or an earlier dry-docking to permit a permanent
repair.
7. Conclusion
In this study an examination of the entire vessel below the waterline should be
carried out by a competent diver using closed circuit television with two-way
communication capable of being monitored by the Marine Surveyor as required
Through this study, it is possible to obtain the appropriate survey angle of towfish
by using data of depth and distance collected from the field. Therefore, it is
possible to prevent degradation of sonar data due to inexperienced operations and
to obtain good sonar data to analyze damage of underwater structure. Based on the
accurate sonar data, which is the result of this study, it is considered that reliable
safety evaluation of underwater structures is possible.
8. Reference
https://diving-ms.com.ua/en/articles/91-in-water-survey-of-ships-afloat/
https://en.wikipedia.org/wiki/In-water_survey
https://www.researchgate.net/publication/
334654129_Underwater_Inspection_in_Lieu_of_Dry-
Docking_UWILD_using_Remotely_Operated_Vehicles_ROV
http://shippingregs.org/Portals/2/SecuredDoc/Flag/UK/MGN/MGN_546_IWS_-
_Final_March_2017.pdf
https://www.hindawi.com/journals/js/2017/9206898/
