Dropping a deck on your passengers is probably not the best way to impress them, although it might lead to some interesting insurance claims. Looking after your wire ropes will help avoid that unpleasantness, to go by the UK's Marine Accident Investigation Branch, MAIB, report into just such an incident aboard the ro-ro ferry St. Helens at the Fishbourne Ferry Terminal, Isle of Wight.
The same problems also arise with lifeboat and fast rescue boats, so the lessons regarding proper lubrication and maintenance of wire ropes goes beyond this particular incident.
At 2221 on 18 July 2014, the starboard forward mezzanine deck on board the UK registered roll-on roll-off passenger ferry St Helen partially collapsed, causing injuries to a crewman and several passengers.
The ferry was berthed at the Fishbourne ferry terminal, Isle of Wight, and the mezzanine deck was being lowered in preparation for the disembarkation of the cars parked on it. The injured crewman, who was rendered unconscious from a head injury, and three passengers, who had suffered a variety of minor injuries while seated in their cars, were taken to hospital. None of the injured remained in hospital overnight.
The mezzanine deck collapsed when its inboard steel wire ramping rope suddenly parted. This caused the forward inboard corner of the suspended deck to drop from a height of about 2m and hit the main deck below. The force of the impact caused the failure of one of the mezzanine deck’s main structural beams.
Post-accident analysis of the failed wire rope found that it had suffered a significant amount of mechanical wear. The mechanical wear, which had primarily been attributed to internal and external abrasion caused by a lack of lubrication, had severely diminished the strength of the rope.
Weaknesses in the way that Wightlink had managed the day-to-day maintenance of its vessels and, in particular, their mezzanine decks. This was despite the mezzanine decks being subject to regular inspections and mandatory 6-monthly thorough examinations by a Royal & Sun Alliance Engineering Inspection & Consultancy surveyor.
Wightlink was aware of many of the safety issues and contributing factors highlighted in this investigation report. Of note: the absence of a formal mezzanine deck greasing routine had been subject to an internal safety management system non-conformity for over 2 years; the failure to address the non-conformity was highlighted by the Maritime and Coastguard Agency nine months prior to the accident; and the failure to lubricate the steel wire lifting ropes was identified during 6-monthly examinations.
Given this knowledge, and the potential consequences of a rope parting, says MAIB, Wightlink demonstrated little or no appetite to allocate the resources necessary to resolve this long-standing issue. This apparent lack of impetus was probably influenced by an over reliance on its 4-yearly wire rope replacement program and the Royal & Sun Alliance Engineering Inspection & Consultancy and the Maritime and Coastguard Agency’s reluctance to escalate the issue.
On 7 August 2014, the Chief Inspector of Marine Accidents wrote to Wightlink and issued a recommendation to immediately instigate a mezzanine deck steel wire lifting rope maintenance programme, and seek independent assurance that the mezzanine decks on its vessels were of sound condition. Wightlink accepted the recommendation and has taken action to improve the material condition of its mezzanine decks and maintain them in accordance with accepted best practice.
MAIB has recommended that Wightlink, British Engineering Services Ltd and the Maritime and Coastguard Agency designed to improve the overall management of maintenance across the Wightlink fleet and improving the levels of assurance provided by the statutory thorough examination of lifting equipment