Alteration of course with COR offset causes loss of power – DP incident

Comments:

The report discussed the set-up and mode selection for the thrusters and main engines during high power manoeuvres such as alteration of course and heading.  The vessel standing orders were changed accordingly.  Investigation as to why the emergency generator did not connect to the bus bar and therefore aid black out recovery was ongoing.

Considerations from the above event:

  • The DPO should be aware of the vessel’s DP capability taking into account the environmental conditions and in this case the additional thrust required by the centre of rotation (COR) being set at the lay chute;
  • It was not clear whether the rate of turn could have been adjusted to reduce thruster demand.  Considering the COR was set at the stern, it should have been set at a low rate;
  • Was the power management system set up correctly as it should have reduced power demand by activating non-essential tripping as part of black out prevention?
  • It should be questioned whether stopping thruster No 2 contributed to the incident as it may have been reacting as required;
  • What was the problem with the set-up of the emergency generator, was it available for manual start only?
    Stresses the importance of the technical crew being adequately trained to deal with a black-out event.