Inadequate communication and planning causes fouled thruster – DP undesired event

Comments:

During the over boarding of the end termination through the starboard aft chute, the cable laying shift supervisor asked the bridge to isolate thruster No 5 (port quarter) instead of thruster No 6 (starboard quarter). He did not realise he was isolating the opposite thruster and consequently the thruster closest to the lay chute was still running. Moreover, he asked the bridge to move backwards and in the same direction where the end termination was being laid down. This movement contributed to the end termination deployment rope fouling thruster No 6.

Considerations from the above event:

  • There was either a lack of operational planning or it was inadequate.
  • The event highlights the need for accurate and verified communication between key control centres.
  • With three satellite derived position systems on line and the acoustic system on standby the vessel was not complying with the requirements of IMO Circular 645.