Swinging load after loss of position

What happened

During backloading of an empty refrigerated container to a Pipe Supply Vessel (PSV), adverse weather conditions, combined with technical issues and the effect of high thrust wash, resulted in a loss of position of the PSV and an uncontrolled swinging load. There was no damage to equipment and no-one was harmed.

This event will also appear as an IMCA DP Incident report.

What went wrong

• Sudden gusts of wind of around 40 knots created high external forces, which resulted in an increased thruster wash towards the PSV, which caused the PSV to lose position;
• The PSV’s azimuth thruster lost its running DP signal, contributing to the loss of position;
• The PSV was operating outside its Activity Specific Operation Guidelines (ASOG);
• The operational limits of PSVs operating alongside were not considered in the Activity Specific Operation Guidelines (ASOG);
• No-one stopped the job: the operation wasn’t stopped despite alarms indicating the PSV was outside defined operational limits.

Lessons to learn

• Review any (project specific) ASOG to include vessel to vessel operations and the effect that thruster wash can have on vessels alongside;
• Review and update procedures for the lifting of cargo to/from PSVs to reflect the potential for loss of position;
• Ensure personnel responsible for DP operations review and consider the requirements of the ASOGs and document their review process;
• Planning, risk assessing and adhering to operational guidelines and limits is crucial to ensuring safe cargo transfer operations.