201748 Mooring rope caught in thruster

 

A chemical tanker in ballast was unmooring from a river berth with a strong current. The forward breast lines had been simultaneously let go ashore but were still in the water and being winched on board. Suddenly the bow thruster stopped functioning. This event did not affect the manoeuvre and the unmooring was safely completed.

It was discovered that one of the forward breast lines floating on the water surface had become caught in the thruster’s propeller. This caused an overload on the thruster which then ceased functioning. The mooring rope was successfully removed some days later by divers.

Lessons learned
- Always be aware of mooring ropes in the water and their proximity to thrusters.
- If possible, single up lines first so that the number of lines to be retrieved from the water at the moment of leaving the berth is reduced.
- Clear, concise communication between the bridge team and the mooring crew is a necessary component in safe berthing and de-berthing operations.