Following a track on DP causes power issues – DP incident

Comments:

The report finding from the vessel concluded:

  • The initiating event was a sudden increase of propulsion to full ahead.
  • The main cause was attributed to the computer with unexpected thrust allocation.
  • The secondary cause was human factor due to a slow reaction to switch to manual mode.

Considerations from the above event:

  • This is an extremely deepwater operation, although margins are large, DP control is still desirable.
  • The limitation of using DGNSS as the only position reference system should be known and acknowledged by those involved in the operation.
  • From the information available it would seem this could be an operator initiated problem. Chosen settings of gain, corridor limits, rate of turn and speed of the vessel could all have contributed.
  • The operator could have selected the ‘Stop’ function on the DP console to stabilise the situation, instead of selecting joystick.
  • It is important that instructions for switchboard configurations are supplied and followed.
  • The starboard propeller tripped at 100% load; this should not happen.