UK MAIB Safety Digest
The UK MAIB issued this yearSafety Digest including lessons learnt from maritime accidents. One case draws the attention on crew to ensure that they always know the limits of all operationally- critical equipment on their vessels as follows:
A freight ro-ro ferry, with twin propellers andbow thrusters, was forced to abort an attemptto berth in strong winds, at a regular port ofcall when one of her bow thrusters failed as theunit’s maximum operational rating was exceeded.The vessel proceeded to anchorage to await animprovement in weather conditions.
When at anchor, the weather deteriorated andthe anchor chain began to render. The decisionwas taken to weigh anchor and proceed to sea.While the anchor was being weighed the cablerendered against the windlass, which causedcatastrophic damage to the windlass driveshaft and clutch assembly. Once the situationhad been assessed the anchor and chain weremarked and slipped to enable the vessel to getunderway.
The vessel returned to port on the followingday, again in high winds, to make a furtherberthing attempt. On this occasion the vesselwas unable to pass mooring lines ashore beforeshe was set downwind into shallow water, andshe grounded. A harbour tug was made fast aftto assist the vessel to refloat. However, whilethe tug was pulling at full power, the towlineslipped from the towing hook and entered thewater near the vessel’s stern.
The vessel’s crew began to heave the towlineback on board. However, during this processthe line fouled one of the vessel’s propellers,which was still turning, and began to pay outrapidly and uncontrollably, striking and injuringa crewman.
The injured crewman was evacuated by thelocal lifeboat after which a further, successful,attempt was made to refloat the vessel. However,as the crew did not know if the towline hadfouled only one or both of her propellers, thedecision was taken to tow the vessel to sea, intogale force onshore winds, without using thevessel’s engines.
The harbour tug managed to tow the vessel 2miles off the port, where her remaining anchorwas let go. However, within a few hours theanchor began to drag. The decision was takento get underway using the propeller which wasless likely to have been fouled by the towline.Fortunately this proved successful. The anchorwas then weighed and the vessel returned toher original port of departure, where she berthedwithout further mishap.
|
Lessons Learnt 1. The crew were unaware that the bowthruster had a maximum limit of 30 minutes’operation. Had they been aware of thisthe berthing plan could have been revisedto prevent the unit’s failure at a criticalstage of the berthing manoeuvre. Crewsshould ensure they know the limits of alloperationally-critical equipment on theirvessels. 2. The forces acting on the windlass whileweighing anchor exceeded the strength ofthe equipment. Mariners should be awareof the limitations of their vessel’s anchoringequipment, which is “intended for temporarymooring of a vessel within a harbour orsheltered area when the vessel is awaitingberth or tide”. 3. The decision to enter port to attempt toberth was, on both occasions, made withoutinput from the harbour authority as noguidelines for port entry were in place. Harbour authorities should ensure, inaccordance with the requirements of thePort Marine Safety Code, that a formalrisk assessment is conducted to determineguidelines for harbour use in all weatherconditions. 4. There have been many accidents involvinginjuries and fatalities to crew memberswho have been struck by ropes which havefouled propellers. Recovering a rope fromthe vicinity of a turning propeller is ahazardous task; crews should be madeaware of the risks involved in such anoperation. 5. The owners’ Incident Management Teamhad closed up ashore to assist onboarddecision-making when the vessel hadgrounded. Owners should ensure that theyhave emergency response arrangements inplace which enable a proactive evaluationof recovery options to be provided to ships’staff in times of crisis. |
