Report on the investigation of

the grounding of

mv Willy
Cawsand Bay, Plymouth Sound

1 January 2002

Marine Accident Investigation Branch

First Floor
Carlton House
Carlton Place
Southampton
United Kingdom
SO15 2DZ

Report No 31/2002
October 2002
 Extract from

The Merchant Shipping

(Accident Reporting and Investigation)

Regulations 1999

The fundamental purpose of investigating an accident under these Regulations is to

determine its circumstances and the cause with the aim of improving the safety of life
at sea and the avoidance of accidents in the future. It is not the purpose to apportion
liability, nor, except so far as is necessary to achieve the fundamental purpose, to
apportion blame.
CONTENTS
Page

GLOSSARY OF ABBREVIATIONS AND ACRONYMS

GLOSSARY OF TERMS

SYNOPSIS 1

SECTION 1 - FACTUAL INFORMATION 3

1.1 Particulars mv Willy and accident 3

1.2 Narrative 4
1.2.1 Events before anchoring 4
1.2.2 Events at anchor 4
1.2.3 Events after grounding 7
1.3 Chart preparation 7
1.4 Anchor routine 8
1.4.1 Engineering 8
1.4.2 Bridge 8
1.5 Cawsand Bay 8
1.6 Company and master’s orders 9
1.7 Relevant crew 9
1.7.1 The master 9
1.7.2 The chief officer 9
1.7.3 The chief engineer 10
1.7.4 The second engineer 10
1.8 Navigation equipment 10
1.9 Characteristics and history 10
1.10 Engine readiness 10
1.11 Observations from ashore 10
1.12 Environmental conditions 12
1.13 Port control 12
1.13.1 Control of movements, anchoring and mooring 12
1.13.2 Radar and camera coverage 13
1.13.3 Manning 14
1.14 Action taken following the accident 14
1.14.1 QHM Plymouth 14
1.14.2 The MAIB 14

SECTION 2 - ANALYSIS 15

2.1 Aim 15
2.2 The amount of cable used 15
2.3 Detection of dragging 16
2.4 Onboard response 17
2.5 The role of port control 17
SECTION 3 - CONCLUSIONS 18

3.1 Findings 18
3.1.1 Cause 18
3.1.2 Contributing factors 18
3.1.3 Other findings 18

SECTION 4 - RECOMMENDATIONS 20

Figure 1 - Extract of chart BA 30 showing the designated

anchorages in Cawsand Bay

Figure 2 - Extract of chart BA 30 showing Willy’s estimated

anchorage positions, swinging circle and GPS
guard zone

Figure 3 - Diagram showing radar coverage in Plymouth Sound

Annex A - Extract of Willy’s Deck Log Book for 1 January

Annex B - Copy of the MAIB Safety Bulletin 01/2002

GLOSSARY OF ABBREVIATIONS AND ACRONYMS
AB - Able Seaman

BA - British Admiralty

CCTV - Close Circuit Television

DTLR - Department For Transport Local Government and Regions

GPS - Global Positioning System

HCO - Harbour Control Officer

IFO - Intermediate Fuel Oil

kg - kilogram

kW - kilowatt

LOF - Lloyd’s Open Form

m - metre

OOW - Officer of the Watch

QHM - Queen’s Harbour Master

SCOPIC - Special Compensation P and I Clause

SOSREP - Secretary of State’s Representative for Pollution and Salvage

UTC - Universal Time Co-ordinated

VHF - Very High Frequency

VTS - Vessel Traffic Services

GLOSSARY OF TERMS

Ship’s swinging circle – the circle centred on the ship’s anchor, the radius of which is
determined by the length of cable laid out plus the length of the ship.

Bridge swinging circle – as above, but determined by the length of cable plus the horizontal
distance between the ship’s stem and the bridge.
SYNOPSIS

At 2250 (UTC) on 1 January 2002, mv Willy grounded in

Cawsand Bay, Plymouth Sound, after dragging her anchor.
The accident was reported to the MAIB by SOSREP via the
DTLR Duty Officer at 0030 on 2 January, and an
investigation was started immediately. Safety Bulletin 1/2002
(Annex B) was issued on 18 January 2002 on the basis of
preliminary findings.

The following factors contributed to the accident:

• The ship was exposed to strong south-easterly winds in Cawsand Bay which,
together with pitching owing to her light condition and the swell, increased the
loading on her cable and anchor.

• The amount of cable used was insufficient given the prevailing weather conditions,
depth of water, nature of the seabed, and condition of the ship.

• The overall speed at which the anchor was dragged, limited the time available in
which to take corrective action to about 16 minutes.

• The ship’s movement was not detected immediately by the OOW because the
position of the anchor had not been determined accurately, the bridge swinging
circle had not been calculated or plotted, and the GPS guard zone was set at a
distance almost three times the radius of the swinging circle.

• The master was not informed of the situation until about 7 minutes after the anchor
had started to drag.

• The OOW did not start the main engine until ordered to do so by the master.

• The engine could not be started and made available in sufficient time to allow the
ship to be manoeuvred clear of danger.

• No consideration was given to paying out additional cable to stop the anchor from
dragging.

The safety recommendations to ship owners and masters contained in Safety Bulletin
1/2002 remain valid.

1
 Photograph courtesy of FotoFlite
2

Willy
SECTION 1 - FACTUAL INFORMATION
1.1 PARTICULARS MV WILLY AND ACCIDENT

Vessel details

Registered owner : Reederei TMS “Willy”

Manager : Carl F Peters

Port of registry : Limassol

Flag : Cyprus

Type : Product Tanker

Built : 1981, Rensburg

Classification society : Germanischer Lloyd

Construction : Steel

Length overall : 105.75m

Gross tonnage : 3070

Engine power : 1821kW

Service speed : 12.25 knots

Other relevant info : Distance from stem to bridge 90m. Direct

drive engine

Accident details

Time and date : 2250 (UTC) on 1 January 2002

Location of incident : Cawsand Bay, 50°20.18N 004°11.64W

Persons on board : 12

Injuries/fatalities : 0

Damage : Constructive total loss

3
 1.2 NARRATIVE

All times are UTC, and are considered to be accurate to within 3 minutes. All
courses are true.

1.2.1 Events before anchoring

During 30 December 2001, Willy, a German owned and managed product

tanker, discharged her cargo of unleaded petrol at Cattewater, Plymouth. She
then sailed at 2030, with a pilot embarked, for an anchorage in Cawsand Bay to
await further orders. The master had been given a choice of either anchorage
No. 14 or No. 15 (Figure 1) by Longroom Port Control, and agreed with the pilot
that No. 15 would be the better of the two anchorage positions. This was
because it was further to the west and there would be less chance of the ship
impeding the fairway of the western entrance to Plymouth Sound. The master
also advised the pilot of his intention to use 4 shackles of cable in the water.
The master had used 3 shackles of cable the previous night in Cawsand Bay
while waiting for an alongside berth, but considered additional cable to be
appropriate given the uncertainty of the duration of his stay.

The anchorage was approached on a course of about 250° at a speed of 2

knots, with the pilot advising the master of all helm and engine movements.
The engine was put to Half Astern to check the headway as the ship
approached the anchorage, and the port anchor was let go when the pilot
advised that the ship was in the charted position of the anchorage by radar. No
allowance was made for the distance from the radar aerial to the anchor.

1.2.2 Events at anchor

After the anchor had been let go, the engine was reduced to Slow Astern to pay
out 4 shackles of cable to the waterline. During this period, the pilot confirmed
that Longroom Port Control was content with the ship’s position, which the
master also checked by radar. A 3-cable guard zone based on Willy’s position
was set on the Leica MK8 GPS. This was the standard distance used, as lesser
distances had previously led to a large number of false alarms being generated.
The main engine was then shut down.

The following day, the wind was north-east force 3 to 4, and the ship was steady
in her anchorage position. Several safety drills and routine maintenance were
conducted during the day, and the equipment required to make the ship ‘gas
free’ was also rigged on the upper deck. However, this was not used because
of the proximity of local villages downwind. New Year’s Eve was not celebrated
on board.

During 1 January, the wind gradually veered to the south-east and increased.
The master was aware that the ship’s anchorage was now exposed, and he,
personally, monitored the ship’s position on the bridge for much of the

4
 Figure 1
Reproduced from Admiralty Chart 30 by permission of the
Controller of HMSO and the UK Hydrographic Office

Allocated
anchorage

1/2 mile

Chart extract showing the designated anchorages in Cawsand Bay

5
 afternoon. The ship was now pitching heavily in the swell running through the
western entrance to the Sound. Although this increased the loading on the
cable, no movement away from the anchorage position, or any signs that the
anchor was dragging, were detected. Reassured by his checks, the master
returned to his cabin, from where he could monitor the ship’s movement relative
to several buoys, which he could see from his windows. He returned to the
bridge during the evening when the tide was turning, but again no signs of the
ship dragging her anchor were evident; the ship was heading into wind, and
appeared to be steady.

At about 2235, the GPS alarm sounded, indicating the ship was on the limit of
the 3-cable guard zone set in the GPS receiver. The chief officer, who had been
standing at the chart table studying the local charts, immediately checked the
radar and determined that the shore to the north-west was at a range of
between 2.5 and 2.8 cables. He then spent 3 to 4 minutes trying to confirm the
ship’s position. As he was doing this, Longroom Port Control, who had been
alerted by an observer from the shore, called Willy via VHF radio to advise that
the ship was drifting to the west. The chief officer agreed, and immediately
informed the master of the situation by telephone.

Several minutes earlier, the master had felt a sudden movement as the ship’s
head swung towards the north. When told that the ship was dragging her
anchor, immediately he ordered the chief officer to start the engine, then went
directly to the bridge. The order to start the engine was passed to the chief
engineer who, because he was not dressed, immediately relayed this instruction
to the second engineer who was on duty.

When the master arrived on the bridge, he checked the radar and GPS. He saw
the ship was very close to the shore, and that her speed over the ground was
1.3 knots. After confirming the proximity of the shore visually from the port
bridge wing, and discussing the situation with the chief officer, the chief officer
was sent forward to heave in the anchor. During this period, the ship’s speed by
GPS reduced to 0.4 knots.

The second engineer started the engine within 5 minutes of being alerted, but
by the time control was transferred to the bridge, the ship was only about 50m
from the rocks. Although the master immediately put the engine to Full Ahead,
moments later there was a loud bang in the vicinity of the steering compartment;
the propeller had struck the rocks before any discernible movement ahead had
been achieved. The engine was then put to Full Astern, and the chief officer was
ordered to stop heaving in the anchor. The ship, however, did not move, so the
engine was put to Stop.

6
1.2.3 Events after grounding

After being informed by the master, at 2251, that Willy had grounded, Longroom
Port Control immediately tasked the duty tug to assist. The master also advised
Longroom Port Control that Willy was not gas free, and passed the state of her
bunkers. The ship was badly damaged; several cargo tanks had been ruptured,
the steering motors were no longer running, and the engine room was flooded.
Brixham Coastguard assumed responsibility for the co-ordination of the
emergency response, and alerted the police, the fire and rescue service, and the
duty principal counter-pollution and salvage officer. The emergency towing
vessel Far Sky was also tasked to proceed to Plymouth.

The risk of explosion, caused by the residue in the empty cargo tanks,
prevented the use of a helicopter to rescue the crew, and the sea state and
depth of water precluded the use of the Plymouth lifeboat, which had been
launched. The crew were, therefore, evacuated from the ship by the Tamar
coastguard team using cliff lines and a pilot ladder from the shore, and were
clear of the ship by 0204 on 2 January. A 1000m-exclusion zone was then
established around the ship, and approximately 100 people were evacuated
from the village of Kingsand.

On 2 January, a salvage control unit, headed by SOSREP, was set up in support

of QHM Plymouth, and the owner agreed a salvage contract with United
Salvage Ltd under the terms of LOF 2000 with SCOPIC incorporated. An
environment group was set up at English Nature headquarters in Exeter. Venting
of the cargo tanks began on 2 January, and by 5 January it had been confirmed
that the ship was gas free. After removing all fuel oils, other than about 7 tonnes
of IFO, and sealing and pressurising the cargo tanks with compressed air, Willy
was refloated at 1319 on 11 January. She was then taken to Falmouth, where
inspection in dry dock revealed extensive damage to her hull.

1.3 CHART PREPARATION

For the shift from Cattewater to the anchorage, the second officer had drawn a
limiting danger line on the chart, based on chart datum and the ship’s maximum
draught. A departure plan from Plymouth Sound had also been prepared, but
there was no plan to take the ship to the anchorage. The ship’s swinging circle
was not calculated or shown on the chart, either before or after anchoring.

7
 1.4 ANCHOR ROUTINE

1.4.1 Engineering

The engine room was not manned, but the chief and second engineers kept 24-
hour watches as the duty engineer, who was expected to stay dressed and
ready. The second engineer was the duty engineer on 1 January and
conducted a set of engineering rounds at 2200. From anchoring on 30
December, no maintenance was conducted on the main engine, which was
available for use within 10 to 15 minutes. One steering motor was kept running.
On the evening of 1 January, because of the wind and limited sea room at the
anchorage, the chief engineer had told the second engineer that if he received
the order to start the main engine, to do it as quickly as possible.

1.4.2 Bridge

The ship’s position was monitored routinely by radar while at anchor by either
the chief officer or second officer, who alternated 6 hour watches as OOW on
the bridge. The chief officer kept the 0600-1200 and 1800-2400 watches, and it
was normal procedure to log the ship’s position every 2 hours. An extract of the
deck log, showing the radar ranges and bearings recorded on 1 January, is at
Annex A. The chief officer normally checked the ship’s position by measuring
the range from the western head of Plymouth Breakwater, and marking with a
pencil dot the ship’s position on the chart.

An AB was not required to be on the bridge, but was available if required, and
conducted fire and safety rounds every 4 hours.

1.5 CAWSAND BAY

Cawsand Bay lies within the limits of the Dockyard Port of Plymouth, and ships
are allowed to anchor in the designated berths when authorised to do so by the
Queen’s Harbour Master. No dues are charged for ships anchoring within the
limits of the Dockyard Port. There are eight designated anchorage berths within
Cawsand Bay – numbers 11 to 18 (Figure 1). Anchorage No. 15 has a charted
depth of between 9.6 and 9.7m, and the sea bottom in its vicinity is a mixture of
sand and shells.

Advice given in the Admiralty Sailing Directions (NP 27) states:

Anchorage can be obtained in Cawsand Bay (50°20’0N, 4°12’0W) sheltered
from all except SE winds. Mariners should anchor clear of the recommended
track for deep-draught vessels and of the DG range.

8
1.6 COMPANY AND MASTER’S ORDERS

The following extracts are taken from the ship manager’s Navigation and Bridge
Organisation Manual:

Anchoring

…..During anchoring, the Master must ensure that speed over the ground is
monitored. The scope of the cable to be used should provide maximum holding
power……

Requirements for Vessels at Anchor

Once anchored, the ship’s position is to be fixed and the heading noted. The
position of the vessel and the amount of cable paid out is to be entered in the
Deck Log Book and Bell Book. A careful inspection of the swing area, both on
the chart and around the ship, is to be made to ensure vessel will remain clear
of hazards or shoals. The Master shall inform the officer of the watch about the
requirements for safeguarding the vessel at anchor.

The position of the vessel must be checked frequently, plotted on the chart and
entered in the Deck Log Book. The activity of other vessels, change of tide and
swing about the anchor must be carefully monitored. The time of start and finish
of the vessel’s swing is to be recorded on the Deck Log Book. Any unusual
occurrence must be reported to the Master immediately.

1.7 RELEVANT CREW

1.7.1 The master

The master was German. He first went to sea in 1983 and qualified as a ship’s
mechanic in 1987. After spending 3 years at the Hamburg Polytechnic, he
joined Shell as a third officer in 1990, and was promoted to second officer in
1991, and then chief officer in 1994. The master left Shell in 1996 and, after
serving in chemical tankers, joined Carl F Peters in April 2000. He joined Willy
in October 2001. This was his fourth visit to Plymouth in the previous 12
months, and on three of these visits he had anchored in Cawsand Bay.

1.7.2 The chief officer

The chief officer was Slovenian and had been at sea since 1975. He was
promoted in 1979, and had served mainly in product carriers. This was his
seventh contract with Carl F Peters. Since joining Willy on 1 November 2001,
the chief officer had worked every day, during which he had had the opportunity
to sleep about 7.5 hours daily. He was content with the amount of rest time
available, and had never felt particularly tired while on board. Before coming on
watch on the evening of 1 January, the chief officer had not consumed any
alcohol, drugs, or medication.

9
 1.7.3 The chief engineer

The chief engineer was German. He had been at sea since 1964, and joined
Carl F Peters in 1992. He had served on board Willy for 3 years, and had
devised the ship’s planned maintenance system, which was also used on two
sister ships.

1.7.4 The second engineer

The second engineer was Filipino, and had been at sea since 1977. He joined
Willy on 4 December 2001, and was considered by the chief engineer to be a
good engineer who could not have started the engine more quickly than he did.

1.8 NAVIGATION EQUIPMENT

Willy was fitted with 2 bow anchors, each weighing 1445kg, with 8 shackles of
chain cable, which had last been replaced in October 1999. A spare bow
anchor was also carried. The GPS receiver was located above the radar display
and could be monitored by the OOW while seated in the bridge chair. Following
the accident, the GPS receiver was removed from the ship and examined
ashore. Information retrieved from the receiver indicated that the position on
which the 3-cable guard zone was centred was 50°19.85N, 004°10.94W (Figure
2), which was 5.6 cables away from the position when aground.

1.9 CHARACTERISTICS AND HISTORY

When at anchor in ballast, Willy was affected more by the wind than the tidal
stream, and also pitched more because of her light condition. The master had
not experienced any problems when at anchor in Cawsand Bay on previous
occasions, but had dragged anchor at the Maas anchorage (off Rotterdam) on 7
November 2001. On that occasion he decided to weigh anchor and put to sea.
The chief engineer recalled that, 3 or 4 times during his 3 years on board, other
masters had ordered the engine to be running in bridge control, when the
conditions at an anchorage had given cause for concern.

1.10 ENGINE READINESS

The time taken to have the main engine running and in bridge control was
normally between 10 and 15 minutes. This was the time required to start the
various pumps, open the air bottles, start the engine, and transfer control to the
bridge. In an emergency, this could be reduced to about 4 minutes.

1.11 OBSERVATIONS FROM ASHORE

When at anchor in Cawsand Bay, a member of a local Coastwatch group could

see Willy from her sitting room window. The observer had noted that Willy had
been snatching her cable during the afternoon of 1 January and, after assessing
that between about 2320 and 2335 Willy was drifting to the west, she
immediately alerted Longroom Port Control by telephone.

10
 Figure 2

Reproduced from Admiralty Chart 30 by permission of the

Controller of HMSO and the UK Hydrographic Office

GPS guard zone

Position of
grounding

Probable position
of anchor

GPS alarm waypoint

Swinging circle

1/2 mile
Chart extract showing Willy’s estimated anchorage position, swinging circle
and GPS guard zone

11
 1.12 ENVIRONMENTAL CONDITIONS

While at anchor, the following were among the weather forecasts received by
the ship via Navtext for sea forecast area Plymouth:

Issued by the Meteorological Office at 1800 on 31 December

Southeasterly 5 to 7, occasionally gale 8 later in south. Mainly fair.

Good…Outlook following 24 hours: Strong southeasterly winds west of
02W….Gale possible south Fastnet, and south Plymouth for a time.

Issued by the Metereorological Office at 1800 on 1 January

Southeasterly 5-7, occasionally gale 8, Rain later. Moderate or good. Outlook

following 24 hours: strong southeasterly winds gradually easing from the
southwest, occasionally gale force at first in Plymouth.

Records of wind speed, measured by an anemometer sited on Plymouth

breakwater, indicate that on 1 January the wind increased from 15 knots at
1600, to 19 knots at 2200, and to 24 knots at 2300. Gusts of up to 30 knots,
however, were also observed. The wind speed and direction recorded in Willy’s
deck log during the evening of 1 January was south-east, force 7.

High water at Plymouth on 1 January was at 1922, and it was 88% spring tides.
The predicted height of tide at 2240 was 5.2m. It was a brilliant moonlit night.

1.13 PORT CONTROL

1.13.1 Control of movements, anchoring and mooring

All movements of vessels over 20m, and all anchoring and mooring within the
limits of the Dockyard Port of Plymouth are controlled by QHM via Longroom
Port Control. Prohibited anchorages are shown on current BA charts, and
regulations specific to vessel types and condition are contained in The Dockyard
Port of Plymouth Order 1999, which states:

No merchant or other private vessel-

(a) carrying hazardous, dangerous or noxious substances……as cargo; or

(b) which is in ballast having previously carried any such substances as cargo,
but which has not been gas-freed,

shall anchor or moor or secure alongside within the limits of the Dockyard Port
save at a berth specified by the Queen’s Harbour Master.

12
 It also states that such vessels shall not anchor or moor within 1000m of any of
Her Majesty’s vessels at anchor or moored, without the permission of the
Queen’s Harbour Master. There are no other restrictions applicable to ships that
are not gas-free. It is believed that two other ships were at anchor in Plymouth
Sound on 1 January, one in Jennycliffe, and the other bunkering in anchorage
No 2. There were no other ships in Cawsand Bay.

1.13.2 Radar and camera coverage

To assist Longroom Port Control meet its VTS function, radar coverage of
Plymouth Sound is achieved by radar heads located at Longroom, and on
Drake’s Island. The diagram showing the combined radar coverage of these
heads (Figure 3) shows that coverage of the deep water channels and main
anchorages was satisfactory, but that much of Cawsand Bay was in a radar
blind spot. When the pilot initially called, informing Longroom Port Control that
Willy had anchored in No 15, she was painting on radar and the HCO estimated
that she was about 0.5 cable to the south-east of the charted anchorage
position. When Willy was lying to the west of anchorage No. 15, however, she
could not be seen on the radar displays within the Port Control.

Figure 3

Cawsand Bay

Diagram showing radar coverage in Plymouth Sound

- red areas indicate radar blind spots

13
 A CCTV camera located on Maker Light, which should have provided views
across Cawsand Bay during daylight, was found to be unserviceable on the
morning of 2 January.

Planned improvements to the radar and CCTV coverage, which are being
progressed as part of a programme of continuous improvement to the VTS in
Plymouth, will provide enhanced radar and CCTV coverage in Cawsand Bay
when implemented. These are planned to be completed by mid 2003.

1.13.3 Manning

Longroom Port Control is manned 24 hours per day by one of several harbour
control officers – all of whom are Admiralty pilots – and an assistant. None of the
harbour control officers interviewed were aware of any ships previously dragging
anchor in Cawsand Bay.

1.14 ACTION TAKEN FOLLOWING THE ACCIDENT

1.14.1 QHM Plymouth

In addition to continuing with its radar and CCTV enhancements, QHM has also
reviewed the anchorage allocation and monitoring process within Longroom Port
Control, with a view to increasing the active monitoring of ships at anchor.

1.14.2 The MAIB

Following the grounding, which was the latest in a number of similar accidents,
the MAIB issued Safety Bulletin 1/2002 (Annex B), containing recommendations
to ship owners and masters.

14
SECTION 2 - ANALYSIS
2.1 AIM

The purpose of the analysis is to determine the contributory causes and

circumstances of the accident as a basis for making recommendations to
prevent similar accidents occurring in the future.

2.2 THE AMOUNT OF CABLE USED

The amount of cable to be used when anchoring depends upon several factors
including: the depth of water, the nature of the seabed, the amount of swing
room available in relation to navigational hazards and other ships at anchor, the
degree of exposure to bad weather, the rise and fall of the tide, the strength and
direction of the wind and tidal stream, and the duration of the stay at anchor.
Although there are several ‘rules of thumb’ for determining the amount of cable
to be used relating to the depth of water, all of the above factors must be taken
into consideration.

The decision to use 4 shackles of cable was based upon the master’s previous
experience at the anchorage, and the uncertainty of his length of stay. As this
length of cable was between six and ten times the depth of water, depending on
the height of tide, and the conditions initially gave no cause for concern, the
amount of cable used is considered to have been reasonable. The cable also
appears to have been laid out in a controlled manner after the anchor had been
let go.

As the weather and sea conditions worsened, however, the ship became
increasingly exposed to strong south-easterly winds. This forced the ship
towards the edge of her swinging circle and, exacerbated by the ship’s pitching
motion caused by her light condition and swell, increased the loading on her
cable and anchor. For an anchor to achieve its maximum holding power, it is
important that sufficient cable leads along the seabed before rising to the hawse
pipe. In this case, it is probable there was insufficient cable given the prevailing
weather conditions, depth of water, nature of the seabed, and condition of the
ship, to prevent the increased weight from lifting the cable from the seabed
adjacent to the anchor. This would have resulted in the angle of the lead of the
cable from the anchor shackle to rise above the shank axis, thereby reducing
the holding power of the anchor. Had more cable been used, the risk of the ship
dragging her anchor, would have been reduced.

15
 2.3 DETECTION OF DRAGGING

When the master arrived on the bridge, he noticed that the ship’s speed over the
ground by GPS was 1.3 knots. This later reduced to 0.4 knot, possibly as a
result of the scope of the cable increasing in the shallower water and the
variable effects of the wind. Nevertheless, the overall speed at which the ship
dragged her anchor, limited the time available for her crew to detect the ship’s
movement and take corrective action, to about 16 minutes.

Rapid detection was therefore essential, and should have been achievable had it
been possible to continually check the ship’s position relative to her bridge
swinging circle, which was about 220 yards. However, although the ship’s
position was checked periodically, because the position of the anchor had not
been accurately determined, and the swinging circle had not been calculated or
plotted, the OOW had no immediate indication of whether the ship lay inside or
outside her swinging circle. This contributed to the time taken by the chief officer
to confirm the ship was dragging her anchor, after being alerted by the GPS
alarm.

The GPS guard zone, however, did not alert the OOW as soon as the anchor
started to drag. This was because it had been set at a distance almost three
times the radius of the bridge swinging circle. Figure 2 shows an estimation of
Willy’s anchorage position, her bridge swinging circle, and the GPS guard zone.
This is based on the ranges and bearings recorded on 1 January, the
information retrieved from the GPS receiver, the range of the shore when the
GPS alarm sounded, and the accounts of witnesses. It is evident from this
estimation, that the guard zone was not initiated until the ship had laid out her
cable to the east, and the ship would have moved over 0.5 cable out of her
bridge swinging circle before the alarm activated.

Had the GPS guard zone been centred on the position of the anchor, and at a
distance equivalent to the bridge swinging circle, this would have provided
immediate detection of the ship dragging her anchor. Although a margin of error
when deciding the distance might be appropriate to reduce false alarms, this
should be limited to the potential navigational error in determining the position of
the anchor. In this case, considering the distance from the charted anchorage
position to the shore was 4.3 cables, the use of a 3-cable guard zone was
inappropriate.

The master was not informed of the situation until about 7 minutes after the
anchor had started to drag. Had the ship’s movement been detected, and the
master been advised sooner, more time would have been available for him to
initiate corrective action.

16
2.4 ONBOARD RESPONSE

The proximity of the lee shore to the north-west, the delay in confirming the ship
was dragging her anchor, the rate at which the ship was dragging her anchor,
and the notice of the engine, required immediate corrective action to be taken if
grounding was to be avoided. No action was taken, however, until the master
ordered the engine to be started. As a consequence, by the time the engine
was running and in bridge control, it was too late to manoeuvre the ship clear of
danger. This was despite the fact the second engineer managed to have the
engine available in less than half the time normally taken.

No consideration appears to have been given to paying out additional cable,

which is an alternative measure frequently taken when an anchor is found to be
dragging in order to optimise its holding power. Four further shackles were
available, and such action could have been initiated by the chief officer via the
on-watch AB.

In emergency situations, there is considerable benefit to be gained by masters

encouraging OOWs, either through their standing or night orders, or verbally, to
take corrective measures before, or while informing them of the situation. In this
case, had the chief officer started the engine and prepared to work the cable as
soon as he realised the ship was dragging her anchor, valuable time would have
been saved, and grounding might have been avoided.

2.5 THE ROLE OF PORT CONTROL

Longroom Port Control was not actively monitoring Willy’s position at anchor
because she was in a radar blind spot, and the CCTV camera on Maker Light
was either not working or not used, although this would have been of little
assistance during darkness. This situation was not ideal. It is important for a
VTS to have sufficient radar coverage of its area in order to meet safely its
responsibilities towards traffic monitoring, harbour management, and assisting
masters discharge their duties. This was difficult to achieve within Cawsand
Bay, and the plans to improve radar and CCTV coverage in this area are,
therefore, considered to be appropriate.

Notwithstanding this, although Port Control is responsible for allocating

anchorages within Plymouth Sound, the responsibility for monitoring position,
and taking appropriate precautions, rests with masters. The Port Control has an
obvious interest in the safety of all ships in its VTS area, however, and the
action taken to review its anchorage allocation and monitoring process
potentially will improve support to masters when at anchor.

17
 SECTION 3 - CONCLUSIONS
3.1 FINDINGS

3.1.1 Cause

Strong winds caused Willy to drag her anchor and ground.

3.1.2 Contributing factors

1. The ship was exposed to strong south-easterly winds in Cawsand Bay which,
together with her pitching caused by her light condition and the swell, increased
the loading on her cable and anchor. [2.2]

2. There was insufficient cable given the prevailing weather conditions, depth of
water, nature of the seabed, and condition of the ship, to prevent the cable from
lifting from the seabed and reducing the holding power of the anchor. [2.2]

3. The speed at which the ship dragged her anchor, limited the time available for
her crew to take corrective action, to about 16 minutes. [2.3]

4. Rapid detection of the anchor dragging was hindered by its position not being
accurately determined, the swinging circle not being calculated or plotted, and
the GPS guard zone being set at a distance almost three times the radius of the
swinging circle. [2.3]

5. The master was not informed of the situation until about 7 minutes after the
anchor had started to drag. [2.3]

6. The engine could not be started and made available in sufficient time to allow
the ship to be manoeuvred clear of danger. [2.4]

3.1.3 Other findings

1. The use of a 3-cable guard zone was inappropriate. [2.3]

2. The GPS guard zone was centred on a position on the eastern limit of the
swinging circle. [2.3]

3. A further 4 shackles of cable were available but not used. [2.4]

4. Had the chief officer been empowered or prepared to start the engine and work
the cable as soon as he realised the ship was dragging her anchor, valuable
time would have been saved, and grounding might have been avoided. [2.4]

18
5. Responsibility for monitoring the ship’s position, and taking appropriate
precautions to ensure her safety, rested with the master, not QHM. [2.5]

6. The plans to improve radar and CCTV coverage in this area are considered to
be appropriate. [2.5]

7. The action taken by Longroom Port Control, to review its anchorage allocation
and monitoring process, will potentially improve support to masters when at
anchor. [2.5]

19
 SECTION 4 - RECOMMENDATIONS
The MAIB has no further recommendations to add to those contained in Safety
Bulletin 1/2002 (Annex B).

Marine Accident Investigation Branch

October 2002

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 ANNEX A

Extract of Willy’s deck log book for 1 January 2002

 ANNEX B

MAIB Safety Bulletin 1/2002