Rip tide presents problems
- DP Event
- Published on 2 June 2017
- Generated on 22 February 2025
- DPE 02/17
- 1 minute read
Observation
A degraded performance was caused by a rip tide. All DP checks were carried out, and the system's performance was monitored for 20 minutes.
Comments
It was a single rip tide and when it had passed the vessel was set up back in automatic position mode.
There was clear evidence that a degraded performance was caused by the rip tide. A risk assessment was made, all DP set-up checks were carried out and the DP system performance was monitored for 20 minutes.
Other rip tides were not observed and the vessel approached the installation to resume operations.
Considerations
- The observation demonstrates a positive attitude to observing environmental conditions with respect to vessel capability and taking the correct actions to avoid potential dangerous loss of position.
- It is unreasonable to expect any DP system to cope with the sudden change in forces that can be introduced by rip tides which can have a catastrophic effect on the ability of a DP system to maintain position and heading.
- If this was a DP equipment class 2 operation then the report indicates that there was inadequate redundancy with regards to position reference systems.
Latest DP incidents
-
Thorough preparation is key
With 4 of 8 diesel generators running and connected to a closed ring bus, and 7 of the 8 thrusters selected to DP, a DP equipment class 3 MODU was set up in Green mode whilst on standby.
DPE 03/24
5 November 2024
Incident
-
There – but not really there
This DP event occurred on a DP equipment class two supply vessel whilst carrying out cargo operations on the starboard side alongside the asset and working at the lee side in the drift-off position.
DPE 03/24
5 November 2024
Incident
-
Equipment Class 3, even if you operate as 'Class 2'
This case study examines a DP incident on an equipment class 3 multi-purpose vessel while operating in good conditions.
DPE 03/24
5 November 2024
Incident
-
Line of sight
This case study covers events onboard a DP equipment class 2 vessel whilst holding position in a turbine field, with three position reference systems selected into DP – DGPS, HPR and Fanbeam.
DPE 03/24
5 November 2024
Incident
-
DP Drill Scenario
DP emergency drill scenarios are included to assist DP vessel management, DPOs / Engineers, and ETOs in conducting DP drills onboard.
DPE 03/24
5 November 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.