Summary

On 10 December 1993, the Australian flag tanker Osco Star was loading a cargo of petroleum products at the Shell refinery Geelong (Corio). A little after midnight, as the officer of the off-going watch was checking the deck, he opened the sighting port to no.4 port cargo tank and heard the rush of liquid falling into what should have been an empty tank. On checking he found that the gas oil cargo in no.3 centre tank was flowing into no.4 port.

Cargo operations were suspended and an inspection made of the area. It was subsequently discovered that gas oil had also entered the trunk-way to no.4 double bottom ballast tank.

Initially, it was considered that the ship had been over-stressed during cargo operations. However, by late morning on the 11 th, it was accepted that the tank structure had suffered damage due to over-pressurisation, caused by the failure of the pressure/ vacuum relief valve on no.3 centre cargo tank, a valve which is designed to vent the displaced gas in the tank when loading, or to relieve vacuum when discharging.

Substantial damage was sustained by the vessel's structure, with splits occurring between no.3 centre cargo tank and no.4 port wing tank and the trunk-way to no.4 double-bottom ballast tank. The top of the bulkhead between nos.3 and 4 centre cargo tanks was set back approximately 750mm and the main deck above the tank was set up by 116mm.

The Marine Incident Investigation Unit investigated the incident under the provisions of the Navigation (Marine Casualty) Regulations.

Conclusions

1. The structural damage experienced by the vessel, in the vicinity of no.3 centre and no.4 port wing cargo tanks, was caused by an excessive buildup of gas pressure in no.3 centre tank as the tank was loaded. This was, in turn, caused by the failure of the single PIV valve on no.3 centre tank to open and vent the tank.
2. The PIV valve met the International Maritime Organisation standard and was of proven design. However, the cast iron used in the PIV valves on Osco Star resulted in a build-up of rust and cargo residues in the critical area between the valve housing and the edge of the valve disk and also between the valve housing and the top cone.
3. Due to the fact that the ship made relatively few voyages in ballast, the opportunity to overhaul the P/V valves at sea was limited.
4. The Chief Mate knew of a deficiency in no.3 centre tank PN valve but did not ensure that the valve was repaired or that alternative open loading procedures were followed before loading cargo to that tank. It is probable that the need to ensure that the valve was repaired slipped his mind.
5. Other members of the ship's staff were aware of the defect in no.3 centre PIV valve, but no action was taken to rectify the situation, and only a limited and low-key reminder was given to the officer of the watch, and no alternative open loading procedure was suggested.
6. The Third Mate, when handing over his watch, indicated that the PN valve on no.3 centre tank was functioning correctly, without having previously established that this was the case.
7. There was a break-down in procedures in addressing the repair of no.3 centre PN valve and a failure of communications concerning the importance of ensuring the valve worked correctly.
8. The information obtained during the course of this investigation, with particular reference to the report of the Salvage Association, UK, would demonstrate that incidents of over-pressurisation of cargo and ballast tanks, with the associated danger to life and the risk of pollution, occur very much more frequently than is commonly appreciated throughout the maritime industry.

Summary

In the early hours of 29 October 1993, the offshore supply vessel Pacific Commander manoeuvred stern-to the semi-submersible drilling rig Atwood Falcon to back-load some sections of casing. The Master was advised the cargo operation would be of short duration and, as a result, he chose not to use an anchor, making fast with two lines aft and maintaining position, at right angles to the rig, with the bow thruster.

After the planned cargo operation was completed and some further equipment transferred, Atwood Falcon then decided to take the opportunity to top up with cement from Pacific Commander, thereby extending the cargo operation significantly. Weather conditions were good, and the Master continued to maintain position by use of the bow thruster. In the early afternoon, the Mate was unable to maintain the position and the Master decided to suspend operations and let go. During the operation of letting go, a nylon mooring line, jammed on the bitts, parted under strain, injuring the Mate.

Conclusions

It is considered that:

1. The information provided to the Master prior to Pacific Commander going alongside Atwood Falcon gave no indication that the operation would be other than relatively short.
2. Based on the initial information provided to him and his experience in the industry, the Master's decision not to use an anchor on that particular occasion was not unreasonable. However, an earlier exercising of his power of discretion to suspend operations, while he remoored using an anchor, would have been appropriate.
3. Full length nylon mooring ropes should not be used, because of the inherent dangers of their elasticity.
4. The configuration of the capstans and bitts on Pacific Commander, with capstans at a higher level than the bitts and close in fore and aft alignment, is such that the mooring lines are prone to becoming jammed when turned up on both and under tension.
5. As changes in plans can occur at short notice, and as the operations of anchoring and weighing anchor are routine, provided water depth permits, an anchor should be used during cargo operations as a standard procedure for vessels not equipped with directional/azimuth thrusters, unless the operation is limited to a single lift.
6. The planning of cargo transfer operations by rig staff was deficient and subject to ad hoc alterations without proper consultation with the Master of the support vessel.

Summary

In November 1993, two reports of close quarter incidents were brought to the attention of the Inspector of Marine Accidents. In both cases the navigation of the two ships concerned was under the charge of pilots licensed for the Great Barrier Reef inner route. The four ships involved were "regulated" ships within the meaning of the Great Barrier Reef Marine Park Act 1975. Under the Act any ship over 70m, navigating the Reef between Cape York and Cairns (Low Isles), must take a duly licensed pilot.

The Inspector regarded the reports. as "incidents" in that each one was, on the face of it, an event as a result of which serious damage to a ship or the environment might reasonably have occurred, and it was reasonably suspected that the safety of ships' personnel were imperilled.

Incident 1

On 2 November 1993, the south-bound Philippine flag bulk carrier Blossom Forever was slowly overtaking the Indian flag bulk carrier Pearl Prosperity in an area of the Great Barrier Reef where the maximum width of fairway reduced from about 1.5 miles to about 1 mile. The differential in speed meant that the overtaking manoeuvre would take about 45 minutes or about 10 miles to complete.

Both ships, in ballast en route for Hay Point, were of almost identical size, marginally over 180m in length, with deadweight tonnages of 38,852 tonnes and 34,554 tonnes respectively.

The two pilots had been in contact by VHF and it was mutually agreed that Blossom Forever would overtake on Pearl Prosperity's port side. The distance by radar between the two vessels reduced to 143m, with the overtaking vessel between 30 and 60 degrees on the Pearl Prosperity's port quarter. The Pearl Prosperity's Pilot considered that the vessel was unnecessarily close and the passing distance would be less than a cable (185m). The ship's master commented on the fact to the Pilot, who was becoming concerned. He therefore contacted the Pilot on board the Blossom Forever and suggested that he alter course away from the Pearl Prosperity.

The Blossom Forever's Pilot agreed and the distance between the ships increased, and the passing manoeuvre was completed safely.

Incident 2

On 15 November 1993, the Liberian tanker Palm Monarch, of 81,282 tonnes deadweight, was overtaking the Australian bulk carrier Iron Shortland, of 107,140 tonnes deadweight. Both vessels were in ballast, each vessel being in excess of 225m in length. The two ships were in the same area of the Great Barrier Reef as the incident of 2 November, but in this case the vessels were north-bound, Iron Shortland bound for the Westem Australian port of Port Hedland and Palm Monarch for the offshore installation of Challis Venture.

Palm Monarch overtook Iron Shortland and the converging courses put the overtaking ship close ahead with both ships on course to pass to the east of Waterwitch Reef. The Master of Iron Shortland expressed concern at the closeness of the other ship and the Pilot altered the ship's course to port, to pass to the west of Waterwitch Reef and any potential risk of collision was averted.

Conclusions

1. Having studied the available information, the Inspector is satisfied that the ships involved in the reported incidents were unnecessarily close, therefore close quarters incidents did occur and that it was reasonable to regard the reports as "incidents" within the meaning of the Regulations.
2. Given that all ships were aware of the close quarter situation and all those on the respective ship's bridges were alert to the potential danger, the risk of collision, had a failure of machinery or steering gear occurred, was remote.
3. Given the situation on the day, there was no compelling reason for ships to overtake in such close proximity.
4. Although communications were established between the vessels involved and the passing manoeuvres discussed, the general level of planning and discussion of projected manoeuvres and courses was inadequate.
5. Given the limits of the water available within the Great Barrier Reef, close quarter situations are bound to occur from time to time. Where vessels' speeds are close and the overtaking manoeuvre prolonged, the overtaken vessel should, in consultation with the overtaking ship, consider reducing engine revolutions to reduce the time of any close proximity.

Summary

Shortly after berthing at West Swanson dock, Melbourne, on 24 September 1993 the 13280 grt container and general cargo vessel "Iron Flinders", on charter to BHP Ltd, suffered a fire in the waste-heat unit (economiser) which is situated in the main engine exhaust trunking at the base of the funnel.

The fire gained sufficient hold for a hydrogen-iron fire to become established, and the internal tube banks of the unit were completely destroyed before the fire was extinguished some eight hours later by the Melbourne Metropolitan Fire Brigade, assisted by the ship's staff and the use of over 8 tonnes of liquid carbon dioxide.

The investigation revealed a combination of several factors which played an important role in causing the fire. The main ones were:

Poor design.

Poor maintenance and operating procedures, due in part to the inadequate provision of on-board instructions and information and, in part, to a lack of instrumentation on the waste-heat unit.

The initial response to the fire revealed considerable uncertainty about, and a lack of specific training for, this kind of fire on the part of the ship's staff. It also revealed some inadequacies in the type of fire-fighting equipment fitted in the vessel.

Conclusions

1. The fire occurred as the result of a combination of factors:

Soot build-up

in order for the fire to have occurred, there must have been a build-up of soot within the unit. The production of soot in the exhaust gas was probably exacerbated by three factors, namely:

1.  
   • The poor performance of the East German fuel valve nozzles,
   • The high consumption of cylinder oil, particularly following the frequent overhaul of pistons, and
   • manoeuvring into port prior to the occurrence of the fire.

The first two of these may have caused fouling of the waste-heat unit over a prolonged period.

The measure employed to assist in the prevention of fouling was the use of Drew Ameroid "LT' soot release powder injected into the bottom of the unit every third day. The effectiveness of this treatment would be reduced if there had been significant oil vapour carry over.

Cleaning

With the inadequate arrangements for thorough inspection of the unit and no provision for water-washing, the quantity of deposits within the more inaccessible areas of the tube nest could have been considerable.

The only method employed for cleaning the unit was that of soot blowing, carried out twice daily. The check-off sheets, however, which were filled in by the Duty Integrated Rating for the two days at sea prior to arriving in Melbourne, that is the 22nd and 23rd September, indicate that the unit was soot blown only once on each of those days, instead of twice as was the routine.

Ignition

Ignition of the accumulated soot could have been caused by either high exhaust gas temperature or by sparks carried over from combustion into the exhaust gas stream. The engine manufacturers, MAN-B&W, have stated in one of their service letters that "oil-wetted soot" may ignite at temperatures as low as 150 Celsius. If the fire, as is most likely, had been smouldering for some considerable period before "Finished with Engines", then the action of shutting down the feedwater circulation would have assisted the fire to gain a hold by stopping the only means by which the heat of combustion was being removed from the tube banks.

2. The lack of information provided by the manufacturers on keeping the tubes clean if part of the unit was to be run in the "dry" condition, is considered to be a contributory factor to the incident. Similarly, the absence of any instructions from the owners, following similar incidents in recent years, emphasising the importance of maintaining waste-heat units in clean condition to minimise the risk of soot fires, is also considered to have been a contributory factor.

No regular monitoring of the degree of fouling of the unit was carried out. The temperatures of gas flow into and out of the unit were not recorded and no instrumentation was fitted for measuring the pressure differential of the gas flow through the unit. Had the remote alarm for "Uptake Temperature High" been connected, an earlier warning of the fire would have been received.

No information was available on board, either in the equipment manuals, owner's orders, or operating instructions concerning the means by which to fight this type of fire. This is considered to have contributed to delays in tackling the fire by the best means in the early stages.

No reports of similar incidents had been passed to their fleet by the vessel's owners, neither was this type of fire covered in the fire training courses undertaken by the ship's staff.

The ship's fire hoses carried in the engine-room, although complying with the requirements of the regulations, were not the most suitable size for use in this situation. Similarly, the nozzles, of East German design, gave a water flow rate and cone angle not well suited to the cooling of surfaces in confined spaces.

Summary

On 28 July 1993, the off-shore supply ship Maersk Runner was employed running out anchors for the mobile drilling unit Atwood Falcon in the Walkley-l field, on the Australian North-West Shelf.

This operation involved the use of a 64 mm diameter working wire, or "chaser wire", which is used to haul the anchors out to the correct position and then to lower the anchors to the seabed.

As a dedicated chaser wire had not been provided, the ship had been using the starboard, 70 mm towing wire. When this towing wire parted, early that morning, a composite chaser wire, made up from a number of wire pendants shackled together, was used.

In the early part of the afternoon, one of the anchors failed to set in the seabed and had to be lifted and repositioned. As Maersk Runner started to lift this anchor, the composite chaser wire parted at a spelter socket, positioned just off the winch. The Mate was struck and thrown by flaying wire, suffering severe head and pelvic wounds, as a result of which he died.

Conclusions

1. The Mate died as a result of injuries received from being struck and thrown by the chain on the end of the port tugger wire and/or the 64 mm diameter chaser wire.
2. The cause of the Mate being struck by the chain/wire was the failure of the spelter socket at the inboard end of a 200m, 64 mm diameter wire pendant, shackled to the ship's working wire and being used as part of a "composite" chaser wire.
3. The spelter socket failed because of the effects of shock overload when the chaser was "homed" on the anchor.
4. The Mate's standing in an exposed position was brought about by the requirements of the particular operation.
5. The operation of using tugger wires on chaser wires, although not a common or usual practice, is necessary when using a composite wire with connecting shackles and sockets within its length.
6. There was no negligence on the part of the Mate, the Master or crew of Maersk Runner.
7. The long, straight stirrup "Crosby" design of spelter socket is not suitable for spooling on to a winch drum of a diameter the size of the normal working drum.
8. Chaser wires should be of one continuous length, to avoid shackles and spelter sockets being spooled on to the drum, and thus also avoid the need for the use of tugger wires.

Summary

On 12 May 1993, the fully laden, 81,248 tonnes deadweight Bahamas flag tanker Oppama Spirit grounded at Gove, Northern Territory. The ship had been manoeuvring to go alongside the berth, when it experienced a total power loss as a result of the seawater cooling system becoming blocked. While under tow to the anchorage, the ship took a sheer and grounded forward.

The ship was pulled clear by one of the tugs after less than one hour and towed to the anchorage without further mishap.

No damage was sustained by the ship and no oil pollution occurred as a result of the grounding.

Conclusions

It is considered that:

1. The blockage of the sea-water cooling system, which resulted in a total power failure, was caused by mud, sand and shells churned up from the seabed and drawn into the system while the engine was being run astern off the berth at Gove.
2. The decision to abort the berthing and tow the ship out to the anchorage was appropriate.
3. The decision not to use an anchor to stop the sheer to port was appropriate.
4. The two tugs stationed at Gove were under-powered for the task in hand and were unable to stop either Oppama Spirit's sheer to port or the grounding.

Summary

The German flag, 35,303 gross tonnes container ship Berlin Express, while proceeding in auto-pilot steering mode through the dredged cut, in the South Channel, Port Phillip Bay, en route to Melbourne, took a rapid sheer to starboard, as a result of which the ship grounded adjacent to South Channel Pile beacon.

Assisted by two tugs from the Port of Melbourne, the ship was successfully refloated 10 hours later, on the next high tide.

The ship suffered no structural damage, and no pollution occurred as a result of the grounding.

Conclusions

Berlin Express grounded as a result of a rapid sheer to starboard brought about by the rudder moving to starboard 20 degrees.

It is considered that:

1. Although an autopilot human input error is the most straightforward and simplest explanation for the movement of the rudder to starboard 20 and cannot be totally discounted, such an error was unlikely.
2. A momentary systems failure, either of the autopilot or the steering gear, was unlikely.
3. Electrical radiation interference of the electronic control systems, from an outside source, was unlikely.
4. Possibly no conceivable malfunction occurred, instead the movement of the rudder to starboard 20 was the response of the autopilot, under the programmed settings, to that particular set of circumstances.
5. The speed of Berlin Express, on entering the cut, was around 18.5 knots.
6. The effect of squat reduced the under-keel clearance as the ship passed between buoys 11 and 12 to 4.78m. As the ship sheered away from the centre line, this would have been reduced to about 2.75m, which would have had an adverse effect on the ship's manoeuvrability.
7. Those on the bridge acted quickly and correctly but were unable to prevent the grounding.
8. At the speed at which Berlin Express was travelling, once the sheer commenced, grounding was unavoidable.
9. Although regulation 339 of the Port of Melbourne Authority (Amendment) Regulations 1988 is no longer considered appropriate, had Berlin Express been proceeding at a much-reduced speed for passage through the dredged cut, the lateral movement to starboard would not have been so great and, therefore, the grounding would have been less likely to happen.
10. The movement of the rudder to starboard 20, the resultant sheer, and hence the grounding, would most probably not have occurred had the steering been conducted manually.

Summary

On 5 April 1993, Oji Maru No 37, a Japanese long line fishing vessel, was on passage from fishing grounds south-west of North West Cape to Fremantle. Just before midnight local time, it ran aground at full speed on Leschenault Reef, two & a half miles off the coast, about 39 miles north of Fremantle pilot boarding ground. The weather was fine & the visibility clear.

Nobody was injured & no pollution resulted from the grounding.

The vessel sustained bottom damage including a hole in No. 6 fuel tank, which was empty, & lost the use of the rudder. The speed at which Oij Maru No 37 grounded nearly carried it over the reef into deep water, but the skeg lodged fast. At about 0200 on 6 April, the vessel refloated & the Master dropped the port anchor at 0218 on the shore side of the reef.

A tug from Fremantle arrived at the vessel at 2210 and, in the morning of 7 April, Oji Maru No 37 was taken in tow to Fremantle.

At Fremantle, temporary repairs were carried out to the holed tank, the skeg & the rudder. These repairs were completed to the satisfaction of the Australian Maritime Safety Authority surveyor & the vessel left for Japan at 1130 on 11 April 1993.

Conclusions

The grounding of Oji Maru No 37 resulted from the failure to observe the basic principles of navigation & the recommendations of IMO Resolution A.484(XII) in that:

1. The Master failed to navigate the vessel in a professional & careful manner, in that he did not check the vessel's position at sufficiently frequent intervals, on appropriate & up to date charts, to ensure that the vessel followed the planned course.
2. The Master failed to ensure that an appropriately qualified officer was in charge of the watch & in the wheelhouse at all times.
3. The Master should not have relied on an unqualified deck hand to maintain a watch.

Summary

The Malinska, a Maltese flag bulk carrier of 34,752 tonnes deadweight, loaded a full cargo of manganese ore at the Groote Eylandt loading terminal from 23 to 25 April 1993.

While sailing from the port, the ship, which should have cleared via a narrow channel of deep water through a bank stretching southward from Connexion Island, grounded on Burley Shaol, 1.5 miles north of "the gap". Initial attempts to refloat the ship were unsuccessful and 1100 tonnes of cargo had to be off loaded before the ship was pulled off by tugs on 28 April 1993.

Conclusions

It is concluded that:

1. While proceeding towards "the gap", Malinska experienced a strong northerly set, and the position plotted on the chart by the Third Mate at 1820 was incorrect.

2. The Master of Malinska failed to use the radar to best advantage, failed to use parallel indexing or other radar monitoring method, and so was unaware that the ship was being set to the north.

3. The Master failed to fully assess the situation before altering course to starboard, placing undue reliance on the ARPA, misreading or misinterpreting the distance to the collision point, and failing to check the ship's position.

4. When Iron Carpentaria altered course to 145 degrees, to take the ship south of the recommended track, due to the strong tidal effect, a developing collision, or near collision, situation was created.

It is further considered that:

5. Even had Malinska not altered course to starboard and had maintained a heading of 232 degrees, because it had been set to the north, there was a strong possibility of the ship grounding on the bank to the south of Burley Shoal.

6. The bridge procedures on board Malinska were lax, in that there was no bridge management structure and no passage planning had been carried out.

7. Had the Mate been on the bridge for departure, instead of, as more traditionally, on the forecastle, the incident may have been approached with greater awareness and possibly avoided.

8. Alcohol cannot be totally ruled out as a factor that might have affected the Master's judgement.

9. The Master of Iron Carpentaria intended to keep clear of Malinska, to give that ship priority.

10. The actions of the Master of Iron Carpentaria were correct and not inappropriate.

11. Where an inbound vessel is to encounter a loaded outbound vessel in the vicinity of "the gap", it would be appropriate for the inbound vessel to standoff, so as to allow the outbound vessel to clear "the gap", before making the final approach.

12. A navigation aid, located either on Burley Shoal or on the northern side of "the gap", would have provided a visual reference for the Master, alerting him to the fact that the ship was being set to the north and that Iron Carpentaria was still to seaward of "the gap".

13. Before disembarking, the Harbour Master should have drawn the Master's attention to the northerly setting current and warned him of the danger of being set towards Burley Shoal

The aircraft was engaged on an IFR freight operation from Bankstown to Canberra and return. The flight from Bankstown to Canberra was uneventful and the aircraft subsequently departed for Bankstown at 1836 ESuT, carrying about 45 kg of light freight. A flight plan submitted by the pilot indicated the aircraft was to track via Shellys at 7,000 ft, thence to Bankstown outside controlled airspace (OCTA).

The pilot reported to Sydney Flight Service over Shellys at 1900, maintaining 7,000 ft, and estimating Bankstown at 1927. Three minutes later the pilot reported commencing descent, and subsequently reported on descent to Flight Service at 1906 after a frequency change. No further radio transmissions were received from the aircraft. Weather reports indicated that instrument meteorological conditions were prevailing in the area at the time.

The wreckage of the aircraft was located the following afternoon on the eastern slope of Axehead Mountain at an elevation of about 2,145 ft. The damage to the aircraft was consistent with having struck trees at cruising speed in straight and slightly descending flight, on a track of about 2930M. Both fuel tanks were completely disrupted, and the wreckage had been largely incinerated in the subsequent fire.

Later examination of the wreckage indicated the aircraft had been capable of normal operation at the time of the accident.

Recorded radar data showed that at 1906 the aircraft was tracking inbound on the 2200 radial of the Sydney VOR at a range of 50 NM, and passing through an altitude of 5,600 ft. When the aircraft was at a range of about 40 NM from Sydney, at an altitude of about 4,300 ft, it was observed to turn left and take up a track of about 2900, still gradually descending. The aircraft continued to maintain this track for a further 22 NM before it faded from radar. The last recorded altitude was at 2,900 ft. At the time of the accident the aircraft was OCTA and not under radar control. Radar returns from the aircraft transponder were suppressed from radar displays to reduce clutter, in accordance with normal operating procedures.

An examination of the medical history of the pilot showed no evidence of any cardiovascular disease or cerebrovascular disease risk factors. He was aged 49 years and held a current Class 1 medical certificate. An ECG performed at his last medical examination indicated a slight conduction defect, but in the absence of other indications of cardiovascular disease the pilot was assessed as fit.

From the evidence available, the flight path of the aircraft was consistent with the pilot becoming incapacitated as the aircraft descended towards Bankstown. The left turn at 40 NM from Sydney onto a heading of about 2900 is considered to have been unintentional as the subsequent track, which was about 1000 left of the flight planned track, took the descending aircraft towards mountainous terrain which was obscured by low cloud. The final track was not directed to any known tracking aid.

Significant Factor

The pilot probably suffered a sudden incapacitation during flight which rendered him incapable of continuing to safely operate the aircraft.