Chemical Tanker & General Cargo Ship Collision – Investigation Report

This investigation report is referring to the collision between the Norwegian chemical tanker Sundstraum and the Malta registered general cargo ship Kapitan Lus. At 1316 LT on 3 July 2009, the Norwegian vessel Sundstraum and the Malta registered vessel Kapitan Lus collided in the Drogden Channel off Copenhagen. Sundstraum was on route from Tjelbergodden in Norway to Stettin in Poland with a cargo of 3707 tonnes of methanol. The vessel was southbound in the Drogden Channel, with the officer of the watch manning the bridge. Kapitan Lus was on its way from St Petersburg in Russia to Le Havre in France with a cargo of 4193 tonnes of aluminium and 182 tonnes of uranium oxide. The vessel was northbound in Drogden and the bridge crew consisted of the Master, the officer of the watch, a Danish pilot and the helmsman. There was good visibility and no wind or seas worth mentioning in the area.

Accident timeline

At 1000 hours Sundstraum’s second officer took over the navigation watch. There was good visibility and almost no wind. The current was flowing southwards through the channel at about 0.4 knots. After Sundstraum had passed a meeting ship just after 1100 hours, the traffic situation at the northern end of the channel was clear, with the exception of some small leisure craft.

At 1010 hours he reported information about the ship and planned passage to the vessel traffic service for the area (Sound VTS) and continued sailing southbound towards the Drogden Channel.

At 1030 hours Kapitan Lus took on board at pilot at Drogden Lighthouse south of the channel, and set a northbound course at a speed of 8 knots.

Section of map showing Sundstraum’s planned southbound route (red) through the Øresund Strait.

At 1105 hours Kapitan Lus was between buoys 8 and 6, the Master on board noticed that Sundstraum, which was heading south, was in the eastern part of the waterway down towards the Drogden Channel. The Master drew the pilot’s attention to this. On the bridge of Kapitan Lus were a pilot, the ship’s Master, the officer of the watch and a helmsman.

At 1110 hours Sundstraum was located a little to the north of the Drogden Channel. The ship was sailing on the east side of the waterway with course east of the central buoy which indicates the northern boundary of the fairway. At this time Kapitan Lus was 2.2 nautical miles south of Sundstraum and just south of buoy no. 6. When Kapitan Lus passed buoy no. 6, the pilot called the vessel traffic service and asked for identification of the southbound tanker that was approaching.

Map section showing a sketch of Sundstraum’s passage (red solid line) and
Kapitan Lus’ passage (blue solid line), and Sundstraum’s planned passage (red broken line).

At 11.10.30 the vessel traffic service identified the vessel in question as Sundstraum. Immediately afterwards, the vessel traffic service called up Sundstraum and pointed out that it was on the wrong side of the central buoy.

The officer of the watch on Sundstraum, who was alone on the bridge, answered the call from the vessel traffic service and stated that he had moved to port in order to pass a leisure craft that was crossing the waterway from Sundstraum’s port side. The pilot on Kapitan Lus confirmed that there was a light leisure craft in the area at the time in question. At this time Sundstraum was steering 171°. At the same time as the call from the vessel traffic service was answered, Sundstraum started turning to starboard to a new course of 186°. After this turn to starboard, the vessel maintained the course briefly before again turning to port, ending up with a course of 168° (see Figure 5). The officer of the watch on Sundstraum now began calling the Master in his cabin via the telephone/PA system.

At 11:12:36 Kapitan Lus called up Sundstraum and requested that the vessels should pass port to port. The officer of the watch on Sundstraum answered the call and at the same time the vessel again turned to starboard to 187 before again turning back to port. This turn to port was observed by Kapitan Lus and they again called up Sundstraum, 11.14.06, and asked Sundstraum to come starboard over in order to make a port to port passing.

At 11.14.13 Sundstraum’s Master arrived on the bridge. At this time Sundstraum had turned to port to 173 degrees, and was 0.81 nautical miles from Kapitan Lus. Shortly afterwards, Sundstraum again turned to starboard and was set for a port to port passing with Kapitan Lus. When the Master arrived on the bridge, he observed that Sundstraum was on the wrong side of the fairway. The officer of the watch informed him that the ship was yawing. The Master understood the officer to say that he had had to give way to a yacht, and was therefore on the wrong side of the fairway. The Master observed that Sundstraum was heading to starboard and towards the correct side of the fairway. As a result, the Master and the officer became caught up in discussions of how they should navigate through Drogden. This discussion was in progress when Sundstraum for the last time turned to port (11.15.30).

At 11.15.10 the situation, as viewed from Kapitan Lus’ side, was again clarified, and the intention was for a port to port passing with a closest point of approach of 0.07 nautical mile (130 m). Nevertheless, the pilot and Master on board Kapitan Lus were uncertain of Sundstraum’s movements, and the pilot ordered the engine reduced to slow ahead and placed the vessel as far to starboard in the fairway as he could.

Picture from Sundstraum’s S-VDR showing the situation at 11.15.10. The distance between the vessels at this time was 0.49 nautical miles (907 metres).

At 11.15.30 Sundstraum again began to turn to port. The vessel was then 0.37 nautical miles from Kapitan Lus. The Master of Sundstraum became aware of the situation, and he ordered manual steering and told the 2nd officer to put on the lights that showed that the vessel was not under command. Dialogues with those involved have not made it clear whether control actually was switched from autopilot to manual steering. The Master tried to turn the rudder to starboard with the joystick (see Figure 11), but observed that the vessel continued to turn to port. He also observed on the rudder indicator that the rudder did not move.

At the same time, the pilot on Kapitan Lus ordered the rudder hard to starboard and full speed ahead in order to turn the vessel away from Sundstraum, at the same time as 5 short blasts were given on the ship’s whistle.

At 11.16.03 Sundstraum’s Master went to the VHF radio at the rear of the bridge and announced that the vessel was not under command. He then returned to the manoeuvre console and put the engine into reverse. The distance to Kapitan Lus was now 0.21 nautical miles. At this time the pilot on Kapitan Lus realised that his turn to starboard could not prevent collision with Sundstraum. He then ordered the engine put hard astern in the hope that the Sundstraum would pass in front. The pilot soon observed that Sundstraum would not pass in front of Kapitan Lus. He then ordered full ahead and the rudder hard to port to make the vessels stern turning away from Sundstraum to reduce the impact force of the collision.

The situation at 11.16.03.

At 11.16.52 the Master of Sundstraum considered that a collision was unavoidable, and decided at this point that he would try to turn the vessel further to port in order to reduce the angle of collision. He tried to turn to port with the aid of the joystick, but the vessel did not react. Sundstraum and Kapitan Lus collided.

After the collision, Sundstraum was detained by the Danish maritime authorities and anchored up in the area where the collision had taken place. Sundstraum had minor damage to the bows, including leakage into the forepeak tank and somewhat depressed steel in the bow section bulwark reinforcement plate on the starboard side. The vessel remained lying there until all necessary investigations had been completed and the Danish authorities released the vessel. The vessel left the area on the evening of 5 July and continued its voyage to Stettin.

The situation just before the collision, 11.16.51. Sundstraum’s speed had now been reduced to 9.1 knots.

Kapitan Lus sustained damage below the waterline to a wing tank on the starboard side and hold no. 3. The damage caused water ingress into hold no. 3 and the vessel rapidly developed a 10° list to port. Kapitan Lus was detained by the Danish maritime authorities and anchored at 1308 hours. The vessel docked in Copenhagen early in the morning of 4 July for unloading and the necessary temporary repairs. On 21 July the vessel was declared temporarily repaired and was given necessary sailing permit by the classification society. The Danish maritime authorities released the vessel and it left Copenhagen on 22 July 2009.

Root Causes

Interviews were conducted with the personnel involved and inspections made on board both vessels. Data from the Sundstraum’s Simplified Voyage Data Recorder (S-VDR) were downloaded after the accident. In addition data and information were obtained from the autopilot supplier, the rudder manufacturer and the vessel traffic service. Simulations were also performed of Sundstraum’s directional stability and movements at the time of the accident.

The investigation did not reveal any features of the steering or technical faults in the steering gear on board the Sundstraum which explain the oscillatory movement pattern that developed. However, weaknesses were revealed with respect to the operator’s framework conditions for safe operation (safety management system).

1. Sundstraum’s changed movement pattern. The investigation report could not explain conclusively what initiated and maintained the oscillations in the time from 11.10.40 up to the time of the collision. The vessel’s directional stability probably did not change as a result of the squat effect. The vessel was probably on autopilot until a short time before the collision. The oscillations in the period from 11.10.40 and up to the time when the Master arrived on the bridge are probably due to the fact that attempts were made to regain control of the situation by repeated changes in the set heading on the autopilot. Irrespective of why the oscillating movement pattern arose and continued, the Board is of the view that an unexpected situation arose for the crew.
2. The Sundstraum crew’s handling of the situation. The crew of the Sundstraum was not prepared to handle the unexpected situation. There was not an adequate bridge manning to handle the unexpected situation. The bridge crew was not pulling as a team to handle the unexpected situation. A speed reduction at an early stage of events, or alternative ways of steering the vessel were not considered or tried.
3. Bridge manning and lack of training. The passage through the Drogden, which is a shallow, narrow and trafficked waterway, requires full focus from a trained bridge crew of adequate size. The planning of the bridge manning for the passage was based on the assumption that no unexpected situation would arise. Compliance with the operator’s existing procedure for passage planning would have resulted in increased manning on the bridge and a greater possibility of rapidly regaining control of the unexpected situation. The shipping company has left it up to the Master to decide whether to use an optional pilot. The Master chose to sail through the area without a pilot. Strengthening this part of the passage by including an extra navigator (pilot) would have given the bridge crew increased possibility to regain control of the situation. The IMO recommends using a pilot. The bridge crew was probably not adequately familiarized with the vessel’s navigation equipment. The bridge crew was not trained in handling an unexpected situation that requires cooperation, precise communication and implementing alternative ways of manoeuvring the vessel. The shipping company’s safety management system does not make provision for the crew to systematically undergo practical training for such situations. Such training would have further increased the possibility of regaining control when the unexpected situation arose.
4. Decision-making support for the crew from the Sound VTS. There may be a need for further measures to assist mariners in the area with information from the Sound VTS to support decision-making on board.

Lessons to be learned

1. Use of pilot in areas such as the one that the accident occurred is recommended. Sundstraum sailed through Øresund without a pilot on board, and thereby opting out of the safety barrier represented by the pilot. In its safety management system, the operator has left the decision regarding the use of an optional pilot to the ship’s Master. The Board recommends that the operator should consider using a pilot in Øresund and similar waterways in line with the IMO’s recommendations.
2. Drills on ship handling when ship’s steering has been lost. The bridge crew’s lack of training contributed to that they did not react early enough to the situation that had arisen and hence the time available for manoeuvre to regain control was not utilised. The operator’s safety management system does not make provision for the crew to practically drill scenarios where control of the ship’s steering is lost. The investigation report recommended that the operator should make provision for all ship’s crews to practically drill handling of scenarios where control of the ship’s steering is lost.

Source: AIBN