UK MAIB reports a case where an ofshore support vessel sheered to port, when during the transfer of conning position, control of the vessel was lost.
The incident
An ofshore support vessel was proceeding to its allocated berth in harbour; it was calm with a moderate breeze and, although it was dark, visibility was good as the whole area was well lit. The passage into the harbour had been uneventful and a pilot was on board to assist with the pilotage and berthing.
The allocated berth has another support vessel berthed immediately in front and another opposite. As the support vessel reached the berth, speed was reduced in preparation for manoeuvring alongside; the berth was overshot by about 20m, although this was not a concern to the master or the pilot.
At about the same time, conning control was being changed over from the bridge centreline to the bridge wing in preparation for coming alongside.
During the transfer of conning position, control of the vessel was lost and it sheered to port; the bow made contact with the vessel berthed ahead and the stern made contact with the vessel opposite.
Lessons learned
According to UK MAIB, pilotage and ship-handling in harbour requires the highest standards of planning and execution. This manoeuvre had been conducted before by the crew and pilot, who were all familiar with the vessel and the harbour.
However, the situation deteriorated rapidly when control of the vessel was lost during transfer of conning positions. This changeover occurred at a time where there was very little room to recover if anything went wrong.
Assuming that conning the vessel from the bridge wing position was key to safe berthing, then the changeover of control position could have been undertaken after entering the harbour but before the final approach to the berth.
