REPORT General Cargo vessel SCOT TRADER call sign MZFA5 deck cargo overboard 6 January 2001 2001-07-02
REPORT General Cargo vessel SCOT TRADER call sign MZFA5 deck cargo overboard 6 January 2001 Our designation: 080202-0126095 Maritime Casualty Investigation Unit This report can also be found on our Internet Home Page Sten Anderson, Head of unit Telephone: +46-11-191269 Www.sjofartsverket.se (Webbtjänsten-Press-Rapporter/ remisser Reprinting is permitted upon disclosure of the origin of the text THE SWEDISH MARITIME ADMINISTRATION SE - 601 78 NORRKÖPING Tel: +46-11-19 10 00 Fax: +46-11-10 19 49
Content 1 Summary... 1 2 Factual account... 1 2.1 The vessel...1 2.2 The crew...3 2.3 The placement and securing of the deck cargo...3 2.4 Stability...4 2.5 The Weather...5 3 Course of events... 5 3.1 The course of events prior to the loss of deck cargo...5 3.2 The course of events after the loss of deck cargo...6 3.3 Searching for and salvaging the pontoons...6 4 Analys... 7 4.1 The lashings...7 4.2 The drift of the pontoons...7 5 Cause... 8 5.1 Primary cause...8 5.2 Contributing cause...8 6 Remarks... 8 7 Recommendation... 8 8 Damages... 9 8.1 Damages to the ship...9 8.2 Damages to the pontoons...9 9 Re-loading in Oskarshamn... 9 10 Conclusion of the investigation... 9 11 Additional information...10 Appendix: photos
1 Summary The British-flagged general cargo vessel Scot Trader had taken on a cargo in Tallinn, Estonia, consisting mainly of packaged timber loaded in the hold. In addition four pontoons were loaded on the hatch. The four pontoons were components for a fish farm, and each was 2x2x45 meters and weighed 22 tons. While heading south, the wind increased from south 2-3 m/sec. (2 Beaufort) to about 20 m/sec. (8 Beaufort) while at the same time it shifted towards the southeast. After having passed Hoburgen on the southern point of Gotland, the ship encountered port winds and seas from slightly abaft the beam, which caused it to roll violently. When the Scot Trader was almost at the midpoint between Hoburgen and Ölands Södra Grund the deck lashings parted, causing two of the four pontoons to slip overboard. The course was immediately changed to starboard in order to moderate the rolling, and it was decided to proceed to Oskarshamn in southern Sweden to re-secure the deck cargo. The two pontoons that were lost overboard floated very low in the water and presented a hazard to other vessels. The pontoons were subsequently salvaged and brought to Oskarshamn, where they were loaded onboard the Scot Trader again. 2 Factual account 2.1 The vessel Name: Call sign: Port of registry: SCOT TRADER MZFA5 Inverness Gross tonnage: 1585 LOA: 82 meters Page 1
Breadth: Draught: Classification society: 11.5 meters Fwd = 2.9 meters Aft = 3.45 meters GL Year built: 1986 Building material: Propulsion power: Steel 1500 kw Crew: 6 IMO number: 9138769 The Scot Trader was built in 1986 for a West German owner at the Husumer Schiffswerft in what was at that time West Germany, and was named the Wotan. In 1999 the ship acquired British flag with Inverness as her homeport. The superstructure, containing the bridge and the crew spaces, was located sternmost above the engine room. Forward of the engine room was a double bottom, separated into eleven double bottom tanks, and forward of these tanks was the forepeak tank. On this voyage six of the twelve tanks were filled and the other six were empty. The total water ballast on board was 625 tons. The total weight of fuel oil, lubricating oil and fresh water was 93 tons. The hold was located above the double bottom and consisted of one single large cargo space having a length of 51.6 meters. 628 tons of cargo, consisting mainly of packaged timber was carried in this space. A steel hatch measuring 50.3 by 9.0 meters covered the cargo space. The height from the deck to the top of the closed cargo hatch was approx. 2.5 meters. The four pontoons were loaded on top of the hatch. To allow the ship to take on a full deck cargo across its whole width there was an arrangement on each side, placed furthest towards the sides of the hull and extending along the entire length of the hatch. This construction Page 2
consisted of 21 vertical steel supports on which rested a horisontal top rail. The structure was permanent and its height was in level with the hatch. (See photo.) Every two meters on both sides along the length of the hatch were brackets for detachable steel supports. The supports were almost two meters in height. (See photo.) The bridge was conventionally equipped with two radars, one being a daylight radar, a gyrocompass, and DGPS (differential GPS). The main engine was an 8 cylinder MAN B&W Diesel, type 8L20/27, providing 1500 kw and connected to a variable pitch propeller. The Scot Trader could make 11.5 knots at full speed. 2.2 The crew The crew consisted of the master, the chief officer, the chief engineer and three able seamen. The master and the chief engineer were English, the others were Polish. The bridge watch was scheduled in six-hour alternating watches, shared between the master and the chief officer with one lookout on each watch. 2.3 The placement and securing of the deck cargo The four pontoons were placed close together on dunnage on the center of the hatch. According to the contract, the consignor would supply the securing materials. He had provided chains without SWL data (Safe Working Load). The dimension of each link was approx. 80 mm x 40 mm and the thickness of the metal was 9 mm. In addition, stretching screws were provided (these too lacked SWL data), having an eye in one end and a hook in the other. The metal of the hook was flattened and the dimensions were 13 mm x 20 mm. The consignor secured the deck cargo with ten chain lashings. Two chains from the fore part and two from the aft part were stretched from the port and starboard sides of the cargo respectively and secured to the opposite sides of the ship, a so called cross-lashing. Another two chains from the fore part and two from the aft part were stretched fore and aft respectively Page 3
from the four corners of the deck cargo. One chain each from the sides of the cargo ran to the respective side of the ship. All ten chains were tightened by means of stretching screws. The lashing material that was supplied was not acceptable to the master. He insisted that the consignor should provide the ship with 16-mm wire, but this could not be obtained in the port of loading. He then requested that the four pontoons should be welded together and the consignor reluctantly arranged for a length of strip iron to be welded across the four ends of the pontoons. Since this still was not satisfactory to the captain of the Scot Trader the ship's own lashing material was also used. Four web-lashings were arranged along the sides of the deck cargo with 8 tons SWL each. Additionally, 15 timber lashings were arranged, each with 6 tons SWL. All these lashings were made of synthetic fibres. 2.4 Stability In the hold the Scot Trader carried 486 tons of packaged timber, a silo weighing 27 tons, and pontoons and rails weighing 40 tons. Pontoons weighing 67 tons had been placed in the hatch coaming and on top of the hatch the four pontoons weighing 88 tons were loaded. The total weight of the cargo was 708 tons. The bottom tanks were filled with 620 tons of ballast water. In addition the ship carried fuel oil, fresh water and lubricating oil totalling 93 tons. At departure the Scot Trader had a mean draught of 3.17 meters. Also at departure the ship's GM (metacentric height) was 1.98 meters and the GZ (righting arm) was a maximum of 50. The master estimated the ship's rolling period (one complete pendular motion) to be 5-6 seconds at the time the cargo was lost overboard. By applying the formula GM = k(b/t) 2 where k is determined to be 0.5, B is the ship s breadth and T is the time for the rolling period, a rolling period of 5.75 seconds is calculated. The master's observations regarding the rolling period and the time calculated by using the formula correspond well to the calculated GM. Page 4
2.5 The Weather When the Scot Trader left Tallinn the wind was south at 2-3 m/sec. As the voyage progressed the southerly wind increased and at the time of the incident it had reached as much as up to 20 m/sec. and shifted to southeasterly. The seas at the time of the incident had increased to approx. 3 meters and were choppy, according to the master. The barometric pressure sank from 1011 hecto Pascal at the time of departure to 995 hecto Pascal when the pontoons fell over board. 3 Course of events 3.1 The course of events prior to the loss of deck cargo The Scot Trader left Tallinn in Estonia on Thursday 4 January 2001 at 1335 hrs on route to Bergen in Norway. The cargo was secured according to those procedures and by means of such material that could be obtained. The sea was moderate during the first part of the voyage. At midnight Thursday the Rista light was passed and the course 217 was set towards Hoburgen on southern Gotland. Wind and seas increased gradually and by midnight the ship was rolling and pitching in heavy sea. At 2344 hrs the Hoburgen light was on bearing 297 at a distance of 10,3 M (nautical miles) and the course was set at 233. At that time the wind was southeasterly at up to 20 m/sec. and the seas were approx. 3 meters coming from slightly abaft the port beam. This caused the Scot Trader to roll violently. On Saturday 6 January at 0415 hrs the ship lurched violently a few times as much as 45, causing the four pontoons to tear loose of their lashings. Two of the pontoons slipped into the sea from the starboard side in position N 56 32.6 E 17 39.7. Page 5
3.2 The course of events after the loss of deck cargo Immediately after the pontoons had gone over board the course was altered to starboard in order to lessen the rolling and the course was set towards Ölands Norra Udde. The master contacted the MRCC, reported what had happened and stated his position. At 0600 hrs the MRCC broadcast a navigational warning which was subsequently upgraded to a PANPAN message (notice of warning). All through Saturday and Sunday and until the forenoon on Monday the MRCC notice of warning was broadcast at regular intervals. The Scot Trader continued to Oskarshamn where she was moored on 6 January at 1445 hrs. 3.3 Searching for and salvaging the pontoons A helicopter located the pontoons at 1015 hrs and it was established that they were drifting at approx. 335 at a speed of approx. 0.5 knots. After having drifted for about six hours the distance between the two pontoons was 0.6 M (approx. 1100 meters). A salvage tug was contracted during the day but could not go to sea because of the poor weather. During the afternoon a Coast Guard aircraft tried to locate the pontoons, but could sight only one of them. At 1025 hrs on 7 January both pontoons were sighted again. Since they had last been observed 24 hours earlier they had both drifted towards the northeast at an average speed of 0.4 knots. When they were sighted anew the distance between the two units was 1.7 M (approx. 3150 meters). At 1127 on 8 January the tugboat arrived at the first pontoon in position N 56 45.04 E 18 18.81 and made it fast. The second unit was made fast in position N 56 45.85 E 18 23.2 and the tow towards Oskarshamn started at 1415 hrs. The two units were found 2.5 M (approx. 4600 meters) apart and had drifted 31 M during the 58 hours they had been in the water. Page 6
The tow to Oskarshamn went without incident. The tug arrived there on Tuesday morning and the Scot Trader took the two pontoons aboard again. 4 Analys 4.1 The lashings The master was very critical of the consignor's chain lashings. When he was unable to obtain the material (16-mm wire) which in his opinion was necessary to properly secure the deck cargo, he prevailed upon on the consignor's workers to weld a length of strip iron to the ends of the pontoons to keep them together. He also decided to use the ship's own lashing materials, which were synthetic fibre web-lashings. In this way lashings and securing arrangements consisted of welded-on strip iron, chains with stretching screws, and web-lashings. The disparity in elasticity between different lashings prevents attainment of combined effect. The combined effective breaking point was consequently not the sum of the breaking points of the three different securing arrangements. The elasticity of the welded-on strip iron was very limited and the welds broke before the chains and web-lashings had taken very much of the stress. The chains and the web-lashings have more elasticity than the strip iron but less elasticity than the web-lashings. The welds, which were very weak, broke first followed by the stretching screws which hooks opened up and finally the web-lashings parted. 4.2 The drift of the pontoons The pontoons were painted black and floated low in the water, which made them very difficult to discover visually both by aircraft and vessels. Since they floated low in the water it was also impossible to detect them on radars. Thus, they constituted a severe hazard to the traffic in the area. The drift of the two pontoons in the water was not similar. When the tugboat after less than 2,5 days get hold of the pontoons the distance Page 7
between them was 2.5 M. Since they were not kept under observation most of the time the MRCC was forced to monitor a large area. This was done to ensure that the pontoons were within the monitored area. All ships approaching the hazardous area were warned. 5 Cause 5.1 Primary cause The pontoons fell overboard as a result of the ship's severe rolling in combination with being insufficiently secured. Three different securing arrangements, which were not compatible, had been used. 5.2 Contributing cause The master kept on the same course even though the ship rolled severely. A considerable change of course to starboard would have lessened the rolling. 6 Remarks It is remarkable that the consignor in Tallin who, under the contract, was responsible for the securing of the cargo, did not provide or could not obtain acceptable lashing material. The master was well aware that the securing arrangements only marginally complemented each other. Thus, he ought to have changed course, considering the big initial stability with quick and violent rolling. In discussion on board while the ship was moored in Oskarshamn, the master indicated several times that he should have altered his course in order to lessen the rolling. 7 Recommendation If an object, which constitutes a danger to shipping has fallen overboard from a ship and is drifting uncontrolled in the water and presents or will be presenting a safety hazard to shipping in the area, the master of the ship, the shipping company or the owner should be required to salvage the Page 8
object. If that is not done, the Swedish Maritime Administration or another authority should be entitled to take action at the expence of the shipping company or the owner. The Swedish Maritime Administration should submit to the government a proposal to amend the relevant legislation. 8 Damages 8.1 Damages to the ship The pontoons, which weighed 22 tons each, slipped overboard from the severely rolling ship, without damaging the ship in any way whatsoever. 8.2 Damages to the pontoons The pontoons were slightly damaged. Certain unprotected plating became slightly indented. 9 Re-loading in Oskarshamn When the pontoons were taken aboard again in Oskarshamn they were placed two and two on each side on the hatch, resting against cargo supports of steel, which had been mounted. Each two-unit entity was lashed with a great number of 16-mm wire lashings (about 20). Ten triangular brackets, 300 mm x 600 mm and 10 mm thick were welded onto both the pontoons and the hatch. The brackets were located on the insides of the paired pontoons, so that they stopped inward movement towards the ship's centerline, and at the same time the deck cargo supports prevented movement outward toward the hull. (See photos) 10 Conclusion of the investigation The consignor was responsible for providing the securing material and for completing the securing arrangements. The master did not accept the securing material. Page 9
16-mm wire, which was what the master required, was not obtainable in the port of loading. In addition to the consignor's securing materials, the ship's own deck cargo lashings were used. The three different kinds of securing arrangements were incompatible. The wind increased during the voyage to as much as 20 m/sec. and there were choppy 3-meter seas, causing the ship to roll severely. The floating pontoons were very difficult to detect visually and could not be seen on the radars. The pontoons presented a severe safety hazard to shipping in the area. After less than two and a half days the pontoons were salvaged by a tug and towed to Oskarshamn where they were re-loaded. At the time when they were salvaged the pontoons were separated by 2.5 M (approx. 4600 meters). 11 Additional information The pontoons that fell overboard from the ship drifted uncontrolled for more than 48 hours. They were difficult to detect visually and on the radars and presented an obvious danger to shipping. Similar problems to those, which the pontoons presented to shipping, can occur when packaged timber and similar cargo falls overboard from ships. No Swedish authority has the explicit responsibility for handling these problems. If oil or other hazardous substances are discharged from a ship, or in certain cases are in danger of being discharged, the Swedish Maritime Administration can make a ruling according to Chapter 7, section 5 (1980:424) of the Act on pollution from ships. The ruling requires the shipping company or the owner to take action to stop or prevent the discharge. If the ruling is not acted upon, and under certain other conditions, The Swedish Maritime Administration may take action at the expense of the shipping company or the owner. Page 10
As regulated by the Ordinance regarding the removal of wreckage etc. presenting a danger to shipping or fishing (1951:321) the Swedish Maritime Administration may take measures to cause sunken objects to be removed to the satisfaction of the Administration if appropriate actions are not taken by the master, the shipping company or the owner. The same applies if the sunken objects present an appreciable hindrance to fishing. No regulation grants the right to the Swedish Maritime Administration or any other authority to remove a hazard which is not water polluting or does not pose the danger of polluting or a foundered wreck or any large object. An authority, as well as any person, may certainly undertake a salvage operation and make demands for salvage costs, but this seems outdated and not quite appropriate. If an object, which constitutes a danger to shipping has fallen overboard from a ship and is drifting uncontrolled in the water and presents or will be presenting a safety hazard to shipping in the area, the master of the ship, the shipping company or the owner should be required to salvage the object. If that is not done, the Swedish Maritime Administration or another authority should be entitled to take action at the expence of the shipping company or the owner. The Swedish Maritime Administration should submit to the government a proposal to amend the relevant legislation. Page 11
Appendix Page 12