Britain’s Marine Accident Investigation Branch has asked class societies to make continued acceptance of equipment which fails catastrophically dependent on the manufacturer carrying out an investigation into the failure, distributing findings and curing the problem. The recommendation is part of MAIB’s just-released report into the ‘explosion’ of the starboard windlass hydraulic motor on board the oil tanker Stella Voyager.
MAIB made an urgent safety recommendation to the equipment manufacturer, TTS Kocks GmbH, which made the equipment, aimed at identifying the technical causes of the failure of its machinery and determining technical solutions for preventing similar accidents in the future. TTS Kocks GmbH has partially rejected the recommendation. The Chief Inspector of Marine Accidents has written to TTS Kocks GmbH urging them, in the interests of safety, to reconsider the recommendation.
“…the current industry requirements for windlass machinery fail to protect persons
against injury in the event of failure” says MAIB.
MAIB’s synopsis of the incident says: ”On 23 March 2009, the starboard windlass hydraulic motor on board the oil tanker Stella Voyager exploded as the vessel was
attempting to recover her starboard anchor in adverse weather and sea conditions, off Tees Bay, UK. Fragments of the motor and its casing seriously injured the windlass operator, who was evacuated to hospital in Middlesborough by helicopter, where he was treated for a broken leg and injuries to his groin.
”The investigation identified that the catastrophic failure of the windlass, which was manufactured by Friedrich Kocks GmbH, resulted from the anchor chain being ‘heaved in’ under considerable tension, exceeding the machinery’s safe operating limit. Examination of the failed components indicated that the windlass had over-pressurised.
“This accident is one of a series of recent catastrophic failures of anchor windlass
motors supplied by TTS Kocks GmbH and other manufacturers. The number and
frequency of these failures is a serious cause for concern, and on 17 August 2009,
the MAIB, together with the Australian Transport Safety Bureau, the Bundesstelle
für Seeunfalluntersuchung (Germany) and the Bahamas Maritime Authority, issued
a Safety Bulletin highlighting the failures and providing guidance on how they can
be avoided. It made an urgent safety recommendation to TTS Kocks GmbH aimed
at identifying the technical causes of the failure of its machinery and determining
technical solutions for preventing similar accidents in the future. TTS Kocks GmbH has
partially rejected the recommendation. The Chief Inspector of Marine Accidents has
written to TTS Kocks GmbH urging them, in the interests of safety, to reconsider the
”The American Bureau of Shipping has been recommended to submit a proposal to
the International Association of Classification Societies which seeks to ensure: a
revision of its technical requirement for windlass hydraulic motors in order to prevent
the catastrophic failure of this type of equipment; and class approval of equipment
is conditional on thorough technical investigation into the causes of catastrophic
failures being conducted by equipment manufacturers whenever these occur. A
recommendation has also been made to the Oil Companies International Marine
Forum with the aim of providing guidance on weighing anchor, particularly with regard
to the safe operation of windlasses. A further recommendation has been made to TTS
Kocks GmbH intended to improve the technical and operational information it provides
when supplying windlass machinery.