Separate problem with two thrusters caused loss of DP
- DP Event
- Published on 13 September 2016
- Generated on 10 November 2026
- DPE 03/16
- 1 minute read
Incident
The seat for the stop solenoid on the engine was damaged causing a slight air leak causing a reduction in main engine rpm.
Comments
The bow thruster gave an alarm that pitch was at maximum showing 114% on DP display. Investigation concluded that the full starboard maximum limit command/set point of the bow thruster proportional valve had been adjusted to 70%. During maximum pitch request the valve had to be permanently opened with constant and continuous hydraulic oil flow through the proportional valve.
It was concluded that because the valve direction flow was set at 70% this resulted in the valve’s malfunction and pitch stuck at maximum. It was later discovered that the azimuth thruster tripped because of sea water contamination of the gear box oil.
Considerations
- Consideration should always be given to making heading changes in incremental steps, a heading change of 20° in one step during critical operations is not recommended.
- To stop adverse thrust from a rogue thruster it must be shut down and not just deselected from DP control.
Latest DP incidents
-
Watch what you are pressing
While transiting away from a wind farm, the Master of a DP equipment class 2 vessel observed that the vessel was operating in Backup Mode and queried this with the bridge team and attending electrician
DPE 03/26
19 October 2026
Incident
-
The domino effect
The event demonstrates the importance of maintaining the approved DP power configuration, addressing known defects before equipment is relied upon during DP operations, and ensuring DP personnel understand how changes to the generating arrangement can affect redundancy and failure propagation
DPE 03/26
19 October 2026
Incident
-
Lost in calibration
During activity associated with calibration of a vessel Vertical Reference Unit (VRU), the DP control system experienced degradation of its attitude reference arrangement. Shortly afterwards, the vessel generated an Off Position Warning followed by an Off Position Alarm
DPE 03/26
19 October 2026
Incident
-
The UPS and downs
While a vessel was transiting in DP mode, the DPO observed the loss of Gyros 2 and 3 together with alarms from a 230V backup power supply. The telephone system remained powered but was inoperable.
DPE 03/26
19 October 2026
Incident
-
DP drill scenario – Consequence Analysis Class DP2 & DP3
DP drill scenario – Consequence Analysis Class DP2 & DP3
DPE 03/26
19 October 2026
Drill Scenario
The case studies and observations above 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 technical crew.
IMCA makes every effort to ensure both the accuracy and reliability of the information, but it is not liable for any guidance and/or recommendation and/or statement herein contained.
Any queries should be directed to DP team at IMCA. Share your DP incidents with IMCA online. Sign-up to receive DP event bulletins straight to your email.