Separate problem with two thrusters caused loss of DP
- DP Event
- Published on 13 September 2016
- Generated on 16 September 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
-
Know your equipment, or at least where to find the answers
During an update in the Follow Target Mode, the crew noticed an anomaly with joystick control.
DPE 02/26
1 September 2026
Observation
-
New equipment, unexpected consequences
During the operation, a loss of DGNSS correction signals was experienced across multiple vessel DGNSS units.
DPE 02/26
1 September 2026
Incident
-
A chain of small failures leads to a major consequence
While conducting cargo operations on DP a vessel experienced a partial blackout caused by an unexpected shutdown of generator 3
DPE 02/26
1 September 2026
Incident
-
Holding position, losing references
While approaching a turret-moored, weather-vaning offshore installation (FPSO), in preparation for cargo operations, a DP equipment class 2 vessel experienced significant rolling of up to 15–20° due to a long-period swell close to the vessel’s natural roll period, resulting in a resonance effect
DPE 02/26
1 September 2026
Observation
-
DP drill scenario – Loss of seawater cooling pump redundancy
Exercise scenario – Loss of seawater cooling pump redundancy
DPE 02/26
1 September 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.