High-Speed Planing Craft Model Tow Tank Testing

Tow tank testing of high speed planing craft differs from traditional displacement hull testing in several aspects, even when the objectives are similar. While the sinkage and trim of a displacement ship does change with speed, the changes are relatively small and do not result in large changes to their waterline length and wetted surface area. Planing craft, due to dynamic lift, undergo large changes in waterline length and wetted surface area from their at rest values. Additionally, validation of computational fluid dynamics codes for conventional monohull and unconventional multihull planning craft has made necessary the measurement of additional data beyond just resistance and the development of specialized capabilities for planing craft testing. This paper will describe several of the measurement techniques and procedures now utilized at the Naval Surface Warfare Center Carderock Division (NSWCCD) when tow tank testing planing craft.