A small GRP sailing yacht (6.7m) was temporarily anchored in a quiet tidal river while she was being prepared to be taken to her summer anchorage. The owner and his son were standing in the tender alongside the cockpit, detaching some empty drums which had been used to heel the yacht over to reduce her draught for the transit downstream from her winter berth.

Unknown to them, the increasing ebb caused the yacht’s anchor to drag. The yacht, and the two men in the tender, drifted towards overhead 11kV power cables that spanned a bend in the river. The masthead made contact with cables, and the father, who was holding onto the aluminium towrail, received a serious electric shock, which caused his breathing to stop and badly burned his arm.

The injured man’s son was able to clear his father’s airway (he had probably swallowed his tongue as a result of the electric shock) and got him breathing again. He then laid him, unconscious, in the bottom of the tender, and motored away from the yacht which, by this time, had thick smoke coming from the anchor well and then up through the companionway.

A 999 call was made using a mobile telephone, and the son then motored back upstream to the nearest point of access to the river where they were met by the emergency services. The father had begun to regain consciousness, but was taken to hospital where he was placed in intensive care and subsequently received skin grafts for his burns.

The Lessons

1. It is vitally important to know the height of your masthead above the waterline, and the existence and height of any hazards you are likely to encounter. Heights above MHWS of cables and other overhead obstructions such as bridges will normally be found on charts, but this stretch of river was uncharted. Warning signs and other information have been distributed since this accident.

2. The course of the river had almost certainly undercut on the outside of the bend, slowly bringing the deep water closer to the line of the cable over time. All concerned, but particularly electricity supply companies, and other organisations responsible for overhead works close to or crossing waterways, should ensure that such effects are closely monitored. Since this accident, the height of these cables has been raised.

Reproduced by kind permission of the Marine Accident Investigation Branch. Originally published in MAIB Safety Digest 1/2005. www.maib.dft.gov.uk