An investigation of some of the resistance aspects of the catamaran hull

Abstract

A symmetrical hull catamaran with dimensions 1n line with current proposed submarine rescue vessels was designed and tested at several hull spacings in order to determine the effect of separation on resistance. A single hull was tested to assess the relative increase in resistance or interference compared to the infinite separation represented by the single hull results. In general, it was found that the resistance decrease with increasing separations and for certain speeds and separations favorable interference was observed which made the overall resistance slightly less than twice the single hull results. A comparison with the submarine rescue vessels, a Taylor expansion and a comparable single hull ship is made where in the case of the latter the catamaran demonstrates its superiority at speed length ratios greater than 1.2. The effect of trim for the proposed design is also evaluated, resulting in decreased resistance with trim by the stern. A possible method employing the use of a single model to predict the resistance of a catamaran was tested with promising results.