Automatic control – navigation problem

We have recently had reported to us this near-miss concerning an ROV support vessel and an unmanned installation. The vessel was operating under automatic control with the platform selected in the outboard navigation computer as the target destination.

On approaching the 500m zone, the on-shift Chief Officer commenced operations to position the vessel outside the 500m zone for field arrival trials.

However, as a result of his omission to deselect automatic control, the vessel failed to respond as he had expected and continued into the platform 500m zone at a speed of between three and six knots.

The Vessel Master, who was also on the bridge, realised that the automatic control had not been deselected. He changed to manual mode and stopped the vessel short of the platform.

The vessel is reported to have come within 10-60m of the structure.

Following the incident, the vessel departed the 500m zone and satisfactorily completed standard field arrival trials prior to starting DP operations.

The company involved has noted that the incident, which occurred on the UKCS, occurred as a result of the failure to comply with UKOOA’s “Guidelines for the Safe Operation of Offshore Support Vessels”, Section 3 “Way Points”, compounded by operator error. A number of corrective actions have been taken by the company to prevent recurrence of this situation.