The incident

During the mooring of an offshore support vessel at a sea mooring, the crew saw that the hawser was fouled.  The chief officer manoeuvred the ship around the buoy to make sure that the line would provide a clear lead once the hawser had been made fast.


After securing the hawser to the mooring bitts, the chief officer manoeuvred the vessel around the sea buoy. He did not know that a seafarer was still on the foredeck area, coiling a grapple rope.

As the vessel was manoeuvring, the swell and sea state impacted the vessel’s rate of turn, leading it to move ahead rather than turn. This caused in the direction of the mooring buoy to lead aft of the vessel’s port beam and place the hawser line under tension;

In addition, the taut line slipped over the bow fender and bulwarks arrangement and pinned the seafarer against the handrail of the stairs for about  4-5 seconds.

The vessel then moved in the seaway, the line tension became less, and the seafarer was freed. He did not sustain serious injury but experienced some post-event shock as well as bruising and pain.

Probable cause

The following played an important role in the incident, according to IMCA:

  • The design of the sea buoy allowed the floating hawser and messenger to become fouled when floating free;
  • The location of the sea mooring was subject to strong and fluctuating currents (a replacement low profile sea buoy was ready to be deployed upon the vessel’s next arrival in port);
  • The chief officer believed the foredeck to be clear of personnel immediately before starting his manoeuvre around the sea buoy to clear the hawser;

In addition, the conning position at the forward console had blind spots, due to vertical window stanchions, which raise obstacles in the view of the foredeck area, unless the person manoeuvring the vessel moves his field of view. In this case:

  • Confirmation by very high frequency (VHF) radio that the deck was clear, was not obtained; The vessel manoeuvre used to un-wrap the hawser from
  • The sea buoy could place sudden tension on the hawser line as the vessel rotated around the sea buoy. It also could place an adverse lead on the line from the vessel’s central panama lead.

Lessons learned

  • A new low profile sea buoy has been deployed that is more suitable to areas experiencing strong and fluctuating currents;
  • A strict clear deck policy has been enforced for future operations involving vessel manoeuvres while attached to a mooring hawser, including VHF communications confirming that the deck is clear prior to commencing the manoeuvre;
  • A toolbox talk (TBT)/job safety analysis (JSA) review will be held prior to manoeuvring the vessel around a sea buoy that emphasises the clear deck policy and VHF confirmation;
  • An alternative method, used by other persons performing the manoeuvre in previous occasions, involved using the azimuth drives to ‘side walk’ around the buoy, while keeping the buoy facing the bow and not under tension.