Unreliable position reference systems leads to incident
- DP Event
- Published on 29 November 2019
- Generated on 26 December 2024
- DPE 04/19
- 1 minute read
Incident
The end-effect was that the deviation from the set point in surge and sway increased with each oscillation.
Comments
Only two DGNSS were online, with poor signal quality due to the location and environmental conditions. The end-effect was that the deviation from the set point in surge and sway were increasing for each oscillation.
Considerations
- For DP2 operations, the use of only two DGNSS systems is insufficient; a minimum of three systems are to be used based on two principles.
- The importance of monitoring the position reference systems (PRS) screen cannot be overstated; this then ensures that all the PRS agree on the position of the vessel.
- It is evident that the selected PRS were not providing reliable position information and highlights the problems that can be experienced when at least one reliable PRS is not available.
- It was noted that the move was paused at 2005; this should have provided the opportunity to investigate and correct the situation rather than continue with the move.
- It is also worth considering that the erratic movement of the vessel could indicate that the DP system needs retuning.
Latest DP incidents
-
Prepare for 2025 solar activity
This case study covers events that occurred on the same vessel, eight months apart.
DPE 02/24
29 July 2024
Undesired event
-
Know your vessel capabilities and when to stop!
An incident that occurred on an equipment class 2 MODU, during well intervention operations.
DPE 02/24
29 July 2024
Incident
-
Duty/not duty, which is the question?
With no steering control of the port azimuth thruster, and no other thrusters operational, the heading of the FPU could not be maintained.
DPE 02/24
29 July 2024
Undesired event
-
You’ve got the ASOG, so now you’ve got to follow it
This case study examines an incident that occurred on an equipment class 2 MODU, during well intervention operations.
DPE 02/24
29 July 2024
Incident
-
Button trouble
A Dynamically Positioned vessel experienced a loss of Dynamic Positioning (DP) control while installing cable within a wind farm.
DPE 01/24
3 April 2024
Incident
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.