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Unfamiliarity with DP system leads to – DP undesired event

Comments from the report:

Both DPOs had several years’ experience but with a different DP control system where it is common to stop the vessel during a move by reducing speed to 0.0kts.  However, on the system fitted to this vessel a retardation factor is used so speed is reduced automatically when the stop request is made.

Setting a speed at 0.0kt led to an unstable situation.  The master instructed DPOs to keep a minimum speed on DP of 0.1kts and not set speed to 0.0kts

Considerations of the IMCA Marine DP Committee from the above event:

  • Vessel specific familiarisation programmes and operation manuals should capture and make allowance for crew members not being familiar with systems. Each system/vessel has peculiarities which must be taught and learned by the crew onboard.
  • The DP system manufacturer should be involved as it should not be possible for the operator to apply a valid setting which then causes an unstable DP system.
  • It is recognised practice to slow down during a move, but it is not considered good practice to use zero speed.
  • The use of the present position would maintain the vessel in the wanted position.

DP Event

Published: 13 June 2019
Download: IMCA DPE 02/19

Classification:
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The following case studies and observations have been compiled from information received by IMCA. All vessel, client, and operational data has been removed from the narrative to ensure anonymity.

Case studies are not intended as guidance on the safe conduct of operations, but rather to assist vessel managers, DP operators and DP technical crew in appropriately determining how to safely conduct their own operations. Any queries should be directed to IMCA at dpreports@imca-int.com. Members and non-members alike are welcome to contact IMCA if they have experienced DP events which can be shared anonymously with the DP industry.

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