The objective of this manuscript is to present the analysis of 6.1 meter (20 foot) diameter controllable pitch propellers for a twin-shafted, notional, all-electric naval combatant craft. The naval combatant used for the analysis was based on a David Taylor Model Basin (DTMB) 5415 hull form scaled up to 162.5 meters in length with a displacement of 15,263 tons. The basic hull form was modified to accommodate the operational needs including power, energy, general arrangements, and propulsion for a notional all-electric naval combatant with advanced warfare capabilities. The advantages and disadvantages of all-electric and mechanical ships are discussed as well as advantages and disadvantages of fixed pitch and controllable pitch propellers. The controllable pitch propellers (CPPs) are based on a modified DTMB 5168 propeller with three blade root pitch angle settings: the base (original) pitch, +5o, and +10o from the base pitch. The analysis of the propeller's performance was conducted using a 3-D coupled boundary element method-finite element method (BEM-FEM). The effects of spatially varying wake inflow, sheet cavitation, and structural response are considered. Results showed that CPPs have the advantage of helping to avoid or reduce cavitation while maintaining near optimal efficiency across the full range of speeds. However, the results also show that the resultant stresses on the blades and the bolts for a 6.1 meter diameter CPP are too high to be acceptable. Hence, additional studies are needed to reduce the stresses, and to investigate the potential susceptibility of tip vortex cavitation.

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