Confidential Human Factors
Incident Reporting Programme
The Charity
Aviation
Maritime
M2152
Initial Report
During a recreational wreck dive off a chartered dive vessel, a diver was hit by the turning blades of the dive boat’s propeller, sustaining significant injuries. The diver was transferred to the local hospital and had their wounds stitched. Coastguard assistance was not requested.
The wreck is best dived while there is still a weak tide over the site, ie close to slack water. The divers had therefore to be dropped up-tide of the wreck to counter the effect of tide while they descended from the surface to the wreck. Once the skipper was satisfied that they were in the right position, the engine was put into neutral to stop the propellor spinning, and the divers entered the water as a group. They swiftly conducted last minute checks before making themselves negatively buoyant and leaving surface.
On the dive boat, the engine is only put back into gear once is it visually confirmed that all divers have left surface. CCTV coverage of blind spots under the hull provide additional assurance. However in this instance, when forward propulsion was engaged, it collided with the diver who sustained serious injuries.
CHIRP Comment
The effect of tide on the boat meant that it drifted back over the location where the divers had entered the water. Although it was visually confirmed that they had all left surface, the crew on board had no way of knowing that at least one diver remained at a shallow depth, with whom they then collided when the engine was put back into gear.
The use of Surface Marker Buoys (SMB), or the laying of a shot line for the divers to hold while they descend would have provided the dive boat a visual clue to the divers’ locations.
This injury was potentially fatal, and CHIRP has contacted the reporter for additional information to determine what happened. With the reporter’s permission, CHIRP has also contacted the relevant Flag and the appropriate Accident Investigation Authority because of the seriousness of the incident.
Key Issues relating to this report
Situational Awareness- It is very difficult to determine the depth of a diver once they have left surface. This was not adequately taken into account by the dive boat’s helm.
Distractions- The boat manoeuvred before it was clear of the diver. Many stimuli, commercial pressure, fatigue, wrong signal cues from the crew, and overconfidence can cause this.
Alerting- given the severity of the incident, medical attention is required immediately. This did not happen, according to the reporter. What are your medical emergency plans in similar circumstances in your company?