Hubrid Hull Forms for Conceptual High Speed Submersibles

"DoD is interested in small underwater fighter-like vehicles. These submersibles will start from submarines and must carry sensors and/or weapons at a high speed. A part of their route will be passed over the water surface in littoral environment.Drag reduction is the key issue in design of such vehicles because submerged missiles add significant hydrodynamic drag. For surface operations, hydrofoils can both significantly reduce friction and pull missiles out of water. The missiles will besuspended under upper a foil/frame of a hydrofoil-biplane. This biplane is located between side hulls of the submersible.For underwater motions, the missiles are hidden within a vented partial cavity under the frame. The frame special design makes it possible the existence of stable partial cavities with negligible drag. Variation of appendage shapes and pressure in thecavity allows stabilization of this low drag in varying conditions.Phase I work includes elaboration of hybrid hull concepts (including propulsor selection, analysis of seakeeping and possible employment of polymer for additional drag reduction), experimental validation of frame drag reduction by cavitation in a watertunnel, and selection of CFD tools for future detailed design during Phase II. Commercialization will be mainly based on applications of drag reduction by partial cavities to both warships and fast commercial ships."