Model Tests To Study Capsize and Stability of Sailing Multihulls

Sailing multihull cruising yachts cannot be righted from a capsize without external assistance, and so they present a difficult problem for regulatory authorities concerned with commercial operation of such craft. A standard is required which enables their stability to be assessed at a similar level to that of monohull yachts. Unfortunately their stability characteristics and behaviour are very different to those of monohulls, and the normal methods of assessment are not appropriate. Some aspects of multihull capsizing are addressed, with a discussion of the results of an innovative programme of wind tunnel and towing tank tests. It is hoped that the paper will be of assistance in directing others in their assessment of multihull safety, and will provide a technical basis for further discussion of the subject.