Take nothing for granted when seawater is involved might be one of the messages of the preliminary report on the failure of two Marin-Ark evacuation systems aboard the P&O ro-ro ferry Pride of Canterbury issued by Britain’s Maritime Accident Investigation Branch.
Often regarded as a safer alternative to traditional evacuation by lifeboat for passenger ships, the Marin-Ark system, manufactured by RFD Ltd. of Belfast, involves dropping a chute from the ship with a liferaft built-in and passengers or crew sliding down into the waiting liferaft. One fatality is recorded in a chute-type escape system, when the casualty was jammed in a ‘piked’ position with the chute and suffocated but the system has been regarded as generally reliable.
On 1st February this year one of the Marin-Ark systems installed between decks on the Pride Of Canterbury was given an annual test as part of a joint European inspection. As the carriage mounted on hydraulic rams moved outboard to lower the chute and liferaft it caught on the outer doors, which had only partially opened. The carriage continued to move forward and upwards, twisted, broke deck plates loose and sheared the hydraulic rams off their mountings.
However, the liferafts were still tipped off the carriage, landed in the water and inflated as normal. It wasn’t possible to check how securely the chutes were attached and it was considered too dangerous to use them.
The second system was initiated but again fouled on the outer doors. The carriage was still able to move into the correct position and the rafts and chutes deployed normally. When the liferafts were being bowsed-in against the ship, however, the aluminium-clad stainless steel bowsing wires parted under tension.
Investigation showed that, even though the equipment was designed for the maritime environment, the hinges of the outer doors, which were mounted outside the ship, were fouled by salt and corrosion which prevented them from opening. This went unnoticed because there were no instructions to test or maintain the door hinges and the only time they were in use was during the annual inspection.
Similarly, the aluminium channels through which the stainless steel bowsing wires travelled were choked by corrosion, which prevented them moving freely.
Says the report: “The manufacturers inspected all other vessels fitted with similar equipment, and satisfied themselves that the equipment would function if required. They undertook a detailed technical investigation into the incidents and, in consultation with the Maritime and Coastguard Agency, developed modifications to prevent similar faults from occurring in the future. The system was subsequently demonstrated on board Pride of Canterbury and the sister ship Pride of Kent, and found to work correctly.”
So, just because equipment is designed or intended to be virtually maintenance free and suitable for the marine environment, it pays not to take them for granted, and not to wait until an inspection to find out they don’t work as required.