MAIB Safety Digest 3/1995

Marine Accident Investigation Branch (MAIB) - Safety Digest

Contents 1. SHIFT OF CARGO ON BOARD A RO-RO FERRY DUE TO HEAVY WEATHER 4 Narrative .........................................................................................................................4 Observations ...................................................................................................................4 Comment.........................................................................................................................4 2. NEAR MISS NEAR TERMINATION OF TRAFFIC SEPARATION SCHEME6 Narrative .........................................................................................................................6 Observations ...................................................................................................................6 Comment.........................................................................................................................6 3. LOSS OF A SMALL CARGO VESSEL..................................................................8 Narrative .........................................................................................................................8 Observations ...................................................................................................................8 Comment.........................................................................................................................8 4. CAPSIZE OF TUGS ..................................................................................................9 Narrative .........................................................................................................................9 Observations ...................................................................................................................9 Comment.........................................................................................................................9 5. INCIDENT INVOLVING THE RESCUE OF THREE MEN FROM A CARGO TANK ........................................................................................................................................10 Narrative .......................................................................................................................10 Observations .................................................................................................................10 Comment.......................................................................................................................11 6. UNCONTROLLED FLOODING OF A CARGO VESSEL ................................12 Narrative .......................................................................................................................12 Observations .................................................................................................................12 Comment.......................................................................................................................12 7. CHEMICAL TANKER STRANDS WITH A PILOT ON BOARD ...................13 Narrative .......................................................................................................................13 Observations .................................................................................................................13

Comment.......................................................................................................................14 8. SHIFT AND PARTIAL LOSS OF A TIMBER DECK CARGO........................15 Narrative .......................................................................................................................15 Observations .................................................................................................................15 Comment.......................................................................................................................15 9. MAJOR DAMAGE TO A GENERAL CARGO VESSEL DUE TO FLOODING 16 Narrative .......................................................................................................................16 Observations .................................................................................................................16 Comment.......................................................................................................................16 10. SPEEDBOAT TRAGEDY RESULTS IN LOSS OF FIVE LIVES ..................18 Narrative .......................................................................................................................18 Observations .................................................................................................................18 Comment.......................................................................................................................18 11. BARGEMASTER DROWNS AFTER FALLING OVERBOARD...................19 Narrative .......................................................................................................................19 Observations .................................................................................................................19 Comment.......................................................................................................................19 12. CONTACT WITH OVERHEAD POWER CABLES BY A HEAVY LIFT SHEERLEGS PONTOON ..........................................................................................21 Narrative .......................................................................................................................21 Observations .................................................................................................................21 Comment.......................................................................................................................21 13. LOSS OF STERN TRAWLER DUE TO SNAGGING AND DOWNFLOODING 23 Narrative .......................................................................................................................23 Observations .................................................................................................................23 Comment.......................................................................................................................23 14. FLOODING TO TWO FISHING VESSELS THROUGH THEIR BILGE SYSTEMS 24 Narrative .......................................................................................................................24 Observations .................................................................................................................24 Comment.......................................................................................................................24 15. FISHERMAN IS SERIOUSLY INJURED WHILE LOBSTER POTTING ...25 Narrative .......................................................................................................................25

Observations .................................................................................................................25 Comment.......................................................................................................................25 16. STERN TRAWLER CAPSIZES DURING TRAWLING OPERATION ........27 Narrative .......................................................................................................................27 Observations .................................................................................................................27 Comment.......................................................................................................................28 17. TWO COCKLE DREDGERS CAPSIZE ............................................................29 Narrative .......................................................................................................................29 Observations .................................................................................................................29 Narrative .......................................................................................................................29 Observations .................................................................................................................29 Comment.......................................................................................................................30 General ..........................................................................................................................30 18. STERN TRAWLER FOUNDERS DUE TO LACK OF MAINTENANCE.....31 Narrative .......................................................................................................................31 Observations .................................................................................................................31 Comment.......................................................................................................................31 19. MAJOR FACIAL INJURY SUSTAINED WHILE SHOOTING NETS .........32 Narrative .......................................................................................................................32 Observations .................................................................................................................32 Comment.......................................................................................................................32

1. SHIFT OF CARGO ON BOARD A RO-RO FERRY DUE TO HEAVY WEATHER

Before leaving a port in the Republic of Ireland for her home port in Wales, the Master of a 7,836 gross registered tonnage Ro-Ro ferry issued instructions that, because of forecasted winds of force 8 - 9, extra lashings should be secured to all commercial vehicles. Private vehicles were block stowed in the fore and aft extremities of the vehicle deck but usual practice was not to lash them.

The ferry departed at about 2310 hrs with 278 passengers, 33 cars, 14accompanied trailers, 4 unaccompanied trailers and 1 caravan. At first the passage was comparatively smooth due to the lee of the land. By midnight the wind had increased to force 8 from the southwest with a heavy confused swell - predominantly from the south. At about 0045 hrs there were reports that, due to the ferry's movement, damage was being caused in the restaurant and in the duty free shop. However, the movement of the ship was not severe enough to cause concern about the safety of the passengers, as the ship had decreased speed and the stabilisers were in operation. By about 0110 hrs the wind had increased to force 9 - 10 and she was steering a course of070º(T). At about 0125 hrs she took a sudden shear and roll to starboard and then rolled very quickly and very heavily to port. The ferry soon recovered and the Master altered course to 055º(T) placing the seas further on the quarter. The ship continued on passage without further incident and berthed at about 0430 hrs. It was found that all the private vehicles had moved across the vehicle deck and were damaged. Some of the commercial vehicles had moved but because of their lashings, the movement had been restricted and damage was comparatively minor. The only damage caused to the ship herself was a broken window which was hit by a heavy table. Fourteen passengers and six crew members suffered injuries but none of them serious.

Observations 1. The ferry was struck by an abnormal wave which was higher and steeper than the height of waves expected for the force of wind experienced that night.

2. A great deal of the stores and furnishings - including numerous individual seats and seat units, counter units and shop display stands -shifted in the incident as they were not secured against the movement of the ship. 3. None of the lashings to the commercial vehicles failed in the incident. 4. The legs of the trailers had been lowered to the deck.

Comment 1. The ferry company has ensured that all items of heavy furniture have been fastened down on board this particular ferry. Also, displays in the duty free shop will be taken down or secured in the advent of heavy weather.

2. The lowering of the trailer legs was in addition to the recommendations made in Section 5 of the Code of Practice "Roll-on/Roll-off Ships - Stowage and Securing of Vehicles".

2. NEAR MISS NEAR TERMINATION OF TRAFFIC SEPARATION SCHEME

A passenger ship was being overtaken by a reefer ship near the termination of the eastbound lane of a Traffic Separation Scheme. When the vessels reached the end of the lane they were on almost parallel easterly courses, with the reefer ship about a mile from the passenger ship and on her portquarter. It was daytime with good weather and clear visibility.

After clearing the lane the reefer ship intended to maintain her easterly course. The passenger ship, however, was bound for a different port and intended to turn to a north easterly course. The passenger ship contacted the reefer ship by VHF radio and advised her that she was going to start to come to port and would pass around the stern of the reefer ship. The reefer ship acknowledged this and confirmed that she would maintain her own course. The passenger ship started a slow turn to port to a course of 060º, using the auto-pilot controls. These controls included a facility for pre-setting the radius of turn before selecting the new course. A turn radius of 8cables was selected. The passenger ship remained on the 060º course for one minute after which another turn to port was initiated, again with the turn radius set at 8 cables. This second turn was not set to leave the auto-pilot to make the manoeuvre; instead the course selector was adjusted a little at a time, to allow the ship's heading to follow it slowly to port. Four minutes after the initiation of the first turn, the passenger ship had reached a heading of 037º. The reefer ship was just forward of her port beam bearing 305º true at a range of 3.9 cables. After about another minute the passenger ship had reached 021º and the reefer ship was 17º forward of her port beam, bearing 308º at a range of 2.1 cables. The Officer of the Watch on the passenger ship realised that his manoeuvre was not going to plan and reduced the ahead power of the engines by the bridge controls. A collision was only narrowly avoided as the reefer ship passed ahead of the passenger ship at very close range.

Observations 1. The passenger ship was fitted with a data recorder. This showed that as the auto-pilot course selector was being manually adjusted to turn the vessel to port, the rate of turn never exceeded 15º per minute, thereby significantly increasing the radius of the turn beyond the 8 cables originally selected. This effectively put the vessel on a collision track with the reefer ship.

2. The ARPA (Automatic Radar Plotting Aid) on the passenger ship was set to the six miles range. This range and the relatively close range of the reefer ship would not have allowed direct monitoring of its relative motion.

Comment 1. Even if the pre-set turning radius of eight cables had been maintained throughout the turn, the manoeuvre carried out by the passenger ship would still have been dangerous and in contravention of the International Regulations for Preventing Collisions at Sea. 2. Rule 17 of the Regulations required the passenger ship to maintain her course and speed. She should have delayed the start of her turn to port until the reefer ship had drawn safely ahead.

3. Alternatively, there might have been good reasons for the passenger ship to have preferred to alter course at the pre-planned alter course position, rather than 'overshoot' it; for example, to avoid risk of collision with a third vessel. Under these or similar circumstances it would have been acceptable under Rule 2 for the passenger ship to have made a substantial reduction in speed before reaching her alter course position, allowing the overtaking ship to draw ahead at an earlier stage.

3. LOSS OF A SMALL CARGO VESSEL

An 850 gross registered tonnage, single hold dry cargo vessel with a crew offive was employed on regular voyages carrying coal. A full cargo was loaded and trimmed to within 30cm of the hatch covers over the full length of the hold except for the forward 4 - 5 metres.

After departure, the vessel experienced several days of poor weather conditions with wind force 7 - 8 increasing to force 8 - 10 causing seas to break over the hatch covers. Towards the end of the Mate's watch, at 0400hrs, a port list of 4º to 5º was noticed. The Chief Engineer was requested to discharge ballast from the port ballast tank to correct this list. These efforts proved successful, however after a very short period the vessel again started to list to port. On this occasion the list gradually increased until it was estimated to be 40º - 50º. Attempts to correct the list by transferring ballast failed. The Master broadcast a MAYDAY and the crew abandoned the vessel. Three men managed to board a liferaft and were later recovered. The other two were lost. The vessel capsized shortly afterwards.

Observations 1. No clear cause could be established for the capsizing of the vessel. However a shift and liquefaction of the coal cargo must be considered as a possible explanation.

2. The two men who lost their lives had donned survival suits but neither man was able to properly close the zips due to the suits not being large enough.

Comment 1. Advice on the recommended precautions to be taken when loading coal cargoes is contained in Merchant Shipping Notice No M.1250. 2. It is speculation to suggest that the two men who lost their lives might have been saved if their survival suits had fitted properly. However, these suits would have been of very limited value in the unzipped state.

4. CAPSIZE OF TUGS

Several investigations have been undertaken into incidents where tugs have capsized while manoeuvring in the immediate vicinity of the vessels they were assisting.

In two of these incidents the tugs were close to the stern of the larger vessels and, due to restrictions of space in the dock and lock area, were using a comparatively short line. In one case a tug was passing across the stern of the larger vessel, whose engine was still on slow ahead to arrest astern movement, when it came into the influence of the propeller's wash. The intensity of this wash moved the tug athwart ships and removed the slack from the towing line which was secured to the towing hook of the tug, amidships. Once the line became taut the tug started to heel sharply, quickly reaching an angle of 90º. On removal of weight from the line, the tug regained an almost upright condition with minimal flooding. In the other incident the weight in the tug's line was effectively taken at the stern using a gog line (a length of rope used to bowse in the tow rope, sometimes called a gob rope). The vessel being assisted was passing through a narrow dock entrance, causing the tug to be positioned almost directly astern, and was using significant engine power due to there being a highwind. No difficulty was experienced until the tug's gog lined failed, so transferring the line's load to the towing hook amidships. This turned the tug beam on and caused it to heel over. The tug quickly sank, albeit in shallow water.

Observations 1. It is of great good fortune that there was no loss of life in either incident.

2. In the first case, all possible openings in the tug had been secured closed. The benefit of this practice being clearly demonstrated by the limited flooding which occurred. The value of this practice is further emphasised by the other case where the tug sank due to flooding via unsecured openings. 3. The dangers of the larger vessel moving too quickly while a tug is beam on to its towline is well recognised by tug Skippers. However, the potential effects of being caught in a propeller's wash may sometimes be overlooked.

Comment Useful advice on the safety of tugs while towing is contained in Merchant Shipping Notice No M.1531.

5. INCIDENT INVOLVING THE RESCUE OF THREE MEN FROM A CARGO TANK

A 5,800 dwt tanker was on passage to a loading port for a cargo of kerosene; the previous cargo had been naphtha. Cargo preparation required waterflushing of the tanks followed by gas-freeing and entry to hand mop the tankbottoms. The tanker had ten cargo tanks arranged in pairs, numbered 1 - 5from forward, with a centre line bulkhead and a single slop tank aft. The tanks were loaded through individual drop lines and each had its own deepwell pump.

The tanks were flushed by pumping water into No 1 tank then pumping this to No 2 tank and so on down the line of tanks and finally into the slop tank. All pipelines and manifolds were purged back to the slop tank using a purge-air system. Tanks were gas-freed by attaching two water driven fans, one port and one starboard, to the manifold and delivering air through the cargo loading lines. Numbers 1 and 2 port tanks were gas-freed first, exhausting to atmosphere through the tank lids. As they became gas-free other tanks were opened on the port side whilst continuing to vent the gas- free tanks. Once the first tank was gas-free (Lower Flammable Limit (LFL) of less than1% and oxygen content 21%) a Tank Entry Permit was issued and the required safety equipment assembled near the tank opening. One man was in continual attendance on deck and he maintained communications with the Officer on bridge watch. Mopping of the tank bottoms progressed as tanks were tested and passed fit for entry. All was proceeding well, with tank Nos 1 - 4 on the port side having been entered and mopped. At No 5 port tank the Chief Officer tested the atmosphere and obtained readings of 21% oxygen and a gas reading of less than 1%. He and a seaman entered the tank to educt residue from the pump well and they were joined by another seaman a short while later. It was about ten minutes after the third man entered the tank that one of the seamen noticed that the Chief Officer was in trouble and he raised the alarm with the man at the tank opening. The Bridge Officer was immediately informed, the alarm sounded and further assistance arrived on deck. The three men in the tank were seen to be moving around and a rescuer entered the tank wearing breathing apparatus and assisted the Chief Officer and one seaman out of the tank. The third man was more affected by the gas and so a second rescuer in breathing apparatus entered the tank and managed to get him out successfully. Once in the fresh air all three men recovered from the effects of hydrocarbon gas though the most seriously affected man suffered some discomfort for a short period afterwards.

Observations 1. The International Safety Guide for Oil Tankers and Terminals (ISGOTT)Chapter 15, states that after the carriage of naphthas, gasolines, gasoline blending products or special boiling point solvents, benzene or other aromatic hydrocarbons may be present. Overexposure to these can have chronic effects which may lead to blood and bone disorders. The Threshold Limit Value (TLV) for benzene is 10 ppm and it is recommended that special chemical tests are carried out to check for the presence of this substance. The approved Tanker Safety Courses also recommend that product tanks are tested for oxygen, LFL and benzene.

2. The accuracy of gas monitors varies between 0 and 3% provided the equipment is measuring the same gas as that with which it was calibrated. In the case of naphtha this represents a range of between 0 and 420 ppm against a 1% LFL reading. The TLV of naphtha is 300 ppm. 3. Although the Code of Safe Working Practices for Merchant Seamen (COSWP)states that a limit of 1% LFL is acceptable for entry, it also states that it would be safer to use a zero LFL.

Comment 1. The primary cause of the incident was the misreading of the gas monitoring equipment. The monitor had two modes, one measured oxygen and percentage gas whilst the other mode showed percentage gas and percentage Lower Flammable Limit. In this case the oxygen content and percentage gasmode was read. Consequently, though a reading of less than 1% was obtained, this represented a much higher gas content than 1% of the LFL. 2. In view of the possibility that a 1% LFL gas monitor reading can represent a gas concentration in excess of the TLV of naphtha, only a zero LFL should be accepted for entry. 3. The gas concentration came about because of the methods used to clean the tanks and gas- free them. The cascading method concentrated the residue into the after tanks and the efficiency of the gas freeing diminished as more tanks were opened. It is possible that the Chief Officer's judgement was impaired by the accumulated effects of the gas from the cleaning operation. 4. This case does illustrate how a successful rescue was possible because the basic safety requirements of the Code of Safe Working Practice were followed. The crew are to be