Modification of semi-submersible and supercavitating propeller to prevent engine overloaded on high speed craft

Due to the high efficiency of surface propellers at speeds above 35 knots, this type propellers one being used on high speed craft for racing and military performance. Mismatch between engine torque and propeller torque, cause engine overloaded or overspeed. One of the ways to resolve the overloaded state, is propeller modification. In this paper, propeller diameter and expanded area is discussed. Where 3 percent and 3.2 percent of the diameter and expanded area is reduced respectively. After correction, 50 rpm was added to the rpm engine and 1.8 knots of Max speed reduced. Also planing rpm increased from 1700 to 1750. The results are satisfying considering boat technical specification. The method can be optimized for more favorable conditions

Keywords:

Modification Propeller , semi-submersible Propeller , Overload Rotate , Overspeed Rotate