§ Mr. Michael Heseltine
The report has now been submitted to me.
The casualty occurred on 4th March 1972 when the craft overturned whilst crossing from Ryde to Southsea, about a quarter of a mile short of its destination. Twenty-two of 27 persons on board were saved, four were drowned and one is still missing, presumed drowned. The craft became a total loss: this was the first accident to a commercially operated hovercraft involving loss of life.
The main conclusion is that the casualty was due to an unusual combination of circumstances. A strong beam wind against an adverse tide combined to produce a dangerous beam sea in the area of the approach to Southsea. As the 381W craft entered this area, the captain had difficulty in holding his track. He had therefore to counteract the tendency of the craft to drift downwind and at the same time to decelerate ready for transition on to the landing pad at Southsea. The operating technique adopted to cope with these difficult conditions led to low skirt inflation. Model tests have since shown that these conditions can cause this type of craft to capsize.
It is now clear that other methods could have been used to bring the craft safely to shore but at the time of the accident the captain of the craft had no reason to know that the operating technique used was dangerous in these sea conditions. The investigating officer concluded that neither the captain, the operating company nor the manufacturer could be blamed for what happened. I accept this conclusion.
Various actions have been taken since the casualty occurred. First, all hovercraft operating in commercial service now have mandatory upper wind and sea limits in which they may set off, prescribed in an operating permit issued under new legislation which came into operation in June this year. At the time of the casualty such limits were issued for the guidance of operating crews; but the decision whether it was safe to operate a craft in particular conditions was left to the captain's discretion and I am satisfied that in this case he acted responsibly.
Secondly, the manufacturers have laid down safe operating techniques for the craft in conditions similar to that in which the casualty occurred; and the operator's manual is being similarly revised. Thirdly, captains of hovercraft are now required to wear a seat belt. At the time of the accident, this was not a requirement and the captain of the craft fell from his seat and was mildly concussed. Fortunately this did not have any serious consequences, but it might have done.
An important recommendation is that the National Physical Laboratory should carry out further work on the stability of hovercraft generally to enable more precise limits of capability in various operational circumstances to be established; this is being urgently considered and some preliminary experimental work is already being undertaken.