STRUCTURAL ANALYSIS AND DESIGN OF HYDROFOILS AND STRUTS

High speed crafts of different layout are becoming increasingly attractive for use as passenger and car ferries. The foil catamaran is one of the promising concepts. In such vessels the hydrodynamic resistance is minimised by utilising dynamic lift forces on foils to have a minimum of the hull structure submerged. To achieve a maximum lift to resistance ratio the foils should be as slender as possible. Also, the struts which support the foils need to be slender. Moreover, weight is a critical issue for high speed vehicles. For this reason high performance materials are required. Candidate materials are for instance high strength steels, aluminium, titanium or FRP. This paper deals with the design criteria for foil systems, with an emphasis on fatigue criteria.