Recent demands for high-speed vessels operating at Froude number of 0.5 or beyond necessitate careful considerations of the important effects of wave drag. The formulation for Michell's resistance is reviewed for a monohull and further developed for multi-hulls. A "wave-making amplitude function" is introduced and the notion of interference resistance among the hulls is explored. Analytical expressions are derived and applied to a configuration of member hulls, each of which is assumed to be of an arbitrary shape, but with centerplane symmetry. A fast and accurate internet-based "resistance evaluator" using specialized quadrature techniques has been developed at the University of California at Berkeley. Demonstrative computations are shown for assessing the effects of separation and stagger on a catamaran configuration and for optimizing the volumetric distribution in a trimaran configuration. Use of this evaluator for design is illustrated. Validations of the predictions by comparison with experimental data are shown for several multi-hull configurations.