A Scottish ferry grounded in North Uist due to a loose screw in its servomotor.
The UK Marine Accident Branch (MAIB) said the 5,500-gt Hebrides (built 2001) ran over several mooring pontoons in Lochmaddy on 25 September last year after its controllable pitch propeller went down.
There were no injuries but the ferry was damaged and had to be taken out of service and repaired in drydock.
The loss of control was caused by the loosening of a grub screw within a servomotor assembly, MAIB said.
Thread-locking compound had not been used to secure the screw, it added, while service instructions for the maintenance of the motor were not available to ship’s engineers or shore-based service engineers.
In addition, an alarm system that had been recommended by the control system manufacturer had not been fitted.
MAIB also found that the bridge and engine control room teams were not sufficiently prepared to deal effectively with a loss of control in confined waters.
The organisation has recommended that Rolls-Royce Marine verify its processes to ensure that service and inspection instructions provided by the original equipment manufacturers of the components used in its control systems are available to its service engineers and in the documentation provided to vessels.
CalMac was asked to document and process recommendations for safety critical system upgrades received from manufacturers, as well as introducing drills and contingency plans to better prepare its crews to deal with propulsion failures.
