The UK’s Marine Accident Investigation Bureau (MAIB) has launched its report into an allision between a trawler and a moored tug on the port of Hull in 2022. The accident was attributable to a mismatch between the controllable pitch propeller’s management levers when transferring management from the bridge to the engine room, in keeping with the company. 

On June 24, 2022, the Kirkella returned from a fishing voyage and transited up the Humber to her traditional berth at King George Dock in Hull. The grasp took the helm management on the starboard wing station for berthing. At about 0531, the grasp berthed the vessel alongside the pier within the southeastern nook of the terminal, with out incident. The crew handed traces over to the dock, and the vessel was securely tied up by 0606, with two head traces, two stern traces and 4 spring traces. The crew started working out the gangway. 

At 0611, with the voyage absolutely over, the grasp started the sequence for shutting down the ship’s engines. He transferred helm management to the middle console, after which transferred management to the engine room. The first engineer was on responsibility within the engine management room and pressed a touchscreen button to just accept management of propulsion. The engine management room’s pitch management lever was set at 85 p.c, and the propeller shifted to match this (unintended and undesirable) “ahead” setting. 

Seconds later, the Kirkella started to maneuver forward. The first officer was on the bridge and seen virtually instantly, and raised the alarm, simply in time to observe the strict traces half. The grasp referred to as the engine room to order an engine shutdown, and he hit the emergency cease button on the middle console to declutch the engine. 

The ship’s momentum continued to hold her ahead, parting two extra mooring traces and dragging the gangway off the dock. Within 10 seconds, the bow of Kirkella hit the moored harbor tug Shovette amidships, beneath the waterline. The tug started spilling diesel into the harbor and taking over water, however the swift response of one other native tug prevented it from capsizing and sinking. 

Illustration courtesy MAIB

The MAIB’s investigation homed in on the vessel’s propulsion management system, a classy Rolls-Royce Helicon-X3 put in throughout outfitting in Norway in 2018. The Helicon-X3 is a complicated design usually used for advanced DP vessels that require digital management of a number of thrusters. 

SOLAS guidelines and IACS common guidelines require an interlock to stop sudden propulsion management modifications when transferring management between consoles. According to the system’s working handbook, it didn’t have an interlock to stop management switching between the bridge and engine room consoles when the propulsion pitch management lever positions differed between the sending finish and the receiving finish. The Rolls-Royce design was authorised by class in 2016, and the vessel’s particular unit handed manufacturing unit acceptance testing.

The bridge officers have been used to the shortage of an interlock, they usually all the time set the controls to “stop” earlier than switching consoles with a purpose to forestall an abrupt change; this was a casual observe and was not documented in procedures. On the day of the casualty, the primary engineer was busy with administrative work and accepted the switch of management from the bridge to his station with out noticing that the pitch management setting on his console was at 85 p.c – a predictable human error, made extra possible by a protracted 12-hour shift and by a scarcity of formal process, in keeping with MAIB. 

“As fitted to Kirkella, the Rolls-Royce Helicon-X3 propulsion control system did not align to the standard of [IACS] UR M43.12, which required a means to prevent significant alteration of the propelling thrust when transferring control,” MAIB concluded. “The Rolls-Royce Helicon-X3 propulsion control system had been fitted to other vessels with remote control stations in the engine control room. Those systems might also not align with the requirement of UR M43.12.”

The MAIB has issued a discover to trade operators about this potential subject, and the shipowner has requested the OEM to alter Kirkella’s propulsion controls to retrofit an interlock.