Industry safety noticeDP relatedDynamic PositioningLoss of PositionLifting / CraneNear Miss
PSV loss of position and uncontrolled swinging load during backloading
IMCA reports that adverse weather, technical issues and high thruster wash caused a PSV to lose position during backloading, leaving a container swinging uncontrolled. No damage or injuries. IMCA notes the event will also appear as an IMCA DP Incident report.
Source information
- Source
- International Marine Contractors Association
- Investigating authority
- None. Industry safety notice, not a regulatory investigation
- Report / reference no.
- IMCA SF 12/24
- Publication date
- Jun 18, 2024
- Last verified
- Oct 4, 2026
Industry Safety Flash based on a member submission; not a regulatory investigation.
DP details (as documented by source)
- Loss of Position
- Environmental
- Procedural / ASOG Issue
- Human Factors
- Vessel type
- Platform supply vessel (PSV)
- Operation underway
- Cargo backloading alongside
- Environmental conditions
- Adverse weather; IMCA reports sudden gusts of around 40 knots
- Initiating event
- High external forces from gusts increased thruster wash towards the PSV (IMCA)
- Loss of position
- Yes
- Thruster / propulsion
- IMCA reports the azimuth thruster lost its running DP signal, contributing to the loss of position
- Alarm response
- IMCA reports the operation was not stopped despite alarms indicating the PSV was outside defined operational limits
- ASOG / CAM / TAM
- IMCA reports the PSV was operating outside its ASOG, and the ASOG did not consider the operational limits of PSVs operating alongside
- Consequences
- Uncontrolled swinging load; IMCA reports no damage and no injuries
Fields not documented by the source are omitted rather than inferred.
Source / investigation findings: IMCA
Contributing factors
- Wind gusts of around 40 knots and increased thruster wash towards the PSV (summarised from IMCA).
- Loss of the running DP signal to the azimuth thruster (summarised from IMCA).
- Operation continued outside the PSV’s ASOG and defined operational limits (summarised from IMCA).
Lessons learned
Source / investigation findings: IMCA
- IMCA highlights planning, risk assessing and adhering to operational limits for cargo transfer.
- IMCA advises DP personnel to review ASOG requirements and document that review.
- IMCA advises updating PSV lifting procedures and project ASOGs to account for loss of position and thruster wash on vessels alongside.
Gulf of America educational summary
The DP system was giving warnings that the vessel was outside its limits, and the ASOG did not cover the vessel-alongside case. When the limits are exceeded, the lift stops.
- Your ASOG is only useful if it covers the actual operation, including vessels alongside.
- An out-of-limits alarm during a lift means stop the lift.
- Consider thruster wash from your own and neighbouring vessels in the cargo plan.
Plain-language interpretation by Gulf of America. Not a finding of IMCA or any investigating authority.