TSB Canada published its report on the 1 December 2020 incident, where while the crew on the bulk carrier Blue Bosporus were carrying out a free‑fall lifeboat drill at Anchorage 12 in English Bay, British Columbia, the wire rope slings holding the lifeboat failed and it fell approximately 14m to the water.
The incident
On 01 December 2020, while the Blue Bosporus was at Anchorage 12 in English Bay, British Columbia (BC) (Appendix A), a lifeboat drill was planned according to the vessel’s drill schedule. During the drill, the lifeboat was to be lowered to the water using the davit and taken for a test run.
Around 1300,5 the master obtained permission to conduct the drill from the Vancouver harbour master and Victoria Traffic. At 1303, an announcement was made over the vessel’s public address system informing the crew that the lifeboat was to be lowered and taken for a test run in the water.
At 1305, all crew members on the Blue Bosporus mustered at the lifeboat station, with the exception of the second officer who remained on the bridge on anchor watch. The master went from the bridge to the aft section of D deck, where he could observe the drill from a distance of about 15 m.
The chief officer, who would normally supervise the drill, had not supervised a free-fall lifeboat drill on the Blue Bosporus since joining the vessel 2.5 months earlier. As a result, the chief officer asked the third officer to prepare the lifeboat for release as well as supervise the 2 able seafarers who were also part of the drill. The third officer and the 2 able seafarers proceeded to the launching platform. The fourth engineer also proceeded to the launching platform, but left after confirming that engineering assistance was not needed.
Meanwhile, the chief officer stood by on the main deck waiting for the lifeboat to be lowered so that he could board the lifeboat with another crew member and take it for the test run. The bosun stood by the davit controls on the main deck.
The third officer used hand signals to communicate with the bosun to lower the davit so that the lifeboat’s slings could be connected to the hooks on the spreader bar. Once the hooks were within reach, the launching crew took the oval rings and attached them to the hooks on the spreader bar. On the port side, the crew placed the oval ring into the hook. On the starboard side, they placed the oval ring and the eye of the aft starboard sling into the hook, shortening the sling length.
Once the slings were connected, the third officer tested the tension in the slings by pushing them forward with his hand. The third officer then signalled to the bosun to lift the lifeboat slightly in order to increase the tension on the slings.
At 1310, the third officer informed the master, via very high frequency radiotelephone, that the lifeboat was ready to launch. The master gave the third officer permission to continue with the launch, and the third officer removed the safety pin. The third officer directed one of the able seafarers to monitor the release hook and inform him when it was unlatched.
The other able seafarer opened the lifeboat door from outside and stepped aside to let the third officer enter.
The third officer entered the lifeboat and stood beside the coxswain’s chair facing toward the bow of the lifeboat. He then moved the release handle up and down 8 to 10 times in order to build up the hydraulic pressure needed to unlatch the release hook .
During this time, the able seafarer who had opened the lifeboat door climbed onto the small platform at the stern of the lifeboat and then into the lifeboat to observe the third officer unlatch the release hook. The other able seafarer remained on the launching platform.
Once the hydraulic pressure was sufficient, the release hook unlatched, and the lifeboat slid forward approximately 25 cm. At this point, the aft starboard sling failed, followed by the 2 forward slings. The bracket holding the aft port sling onto the lifeboat broke off as well. The lifeboat fell about 14 m into the water.
Analysis
- Condition of slings: The crimp sleeves on the Blue Bosporus’s lifeboat slings had weakened over time as a result of intergranular stress-corrosion cracking.
- Attachment of slings to hooks: The manner in which the slings were attached to the hooks caused the load to concentrate on the aft starboard sling. This, in combination with the weakened crimp sleeves, caused the sequential failure of the slings and the aft port sling bracket.
- Verification of slings: In the absence of any international guidance requiring free-fall lifeboat slings to be verified periodically, inspected before use, and marked with a safe working load, there is a risk that this critical equipment will be overlooked during inspections or its safe limits will be exceeded, leading to an accident.
- Crew practice during the lifeboat drill: Without a complete procedure for conducting a drill that involved launching the lifeboat using the davit, the crew had developed an informal practice that did not address the risk of standing unsecured in the lifeboat, which led to the serious injury of 2 crew members when the lifeboat fell.
- Supervision: If supervisors are required to take an active role during safety critical tasks such as lifeboat drills, their attention will be divided and they will be less able to attend to all aspects of the task, increasing the risk that safety critical items will not be identified in time to prevent an accident.
- Additional restraining devices: There was no additional restraining device in use to protect the crew on the Blue Bosporus from falling when the slings failed.
Probable cause
The crimp sleeves on the Blue Bosporus’s lifeboat slings had weakened over time as a result of intergranular stress-corrosion cracking.
In addition, the manner in which the slings were attached to the hooks caused the load to concentrate on the aft starboard sling. This, in combination with the weakened crimp sleeves, caused the sequential failure of the slings and the aft port sling bracket.
Furthermore, without a complete procedure for conducting a drill that involved launching the lifeboat using the davit, the crew had developed an informal practice that did not address the risk of standing unsecured in the lifeboat, which led to the serious injury of 2 crew members when the lifeboat fell.
Finally, there was no additional restraining device in use to protect the crew on the Blue Bosporus from falling when the slings failed.
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Source: TSB Canada
