A Systems Approach To The Propeller Redesign For The Us Navy Seal Swimmer Delivery Vehicle (Sdv)

This paper details work undertaken at the Massachusetts Institute of Technology (MIT) to improve the overall performance of the Navy SEAL swimmer delivery vehicle (SDV Mk VIII Mod 1) through the design of a wake adapted propeller to replace the existing stock propeller. First, an analysis was conducted of the currently installed propeller using a lifting surface vortex lattice propeller code developed at MIT by Kerwin. This gave the performance required for a new propeller. To start the design process, a lifting line propeller design code developed at MIT by Kerwin was used to find the potential efficiency gains possible with a wake-adapted propeller with minimal hub drag. Then, a circuit model of the propulsion electric motor was derived and coupled with the lifting line program to match the operating point between the redesigned propeller and the motor. The result of this coupled analysis was a numerical prediction for the reduction in battery amperage draw. A prototype propeller was manufactured and tested, resulting in an 8.9% reduction in battery current discharge.