effect of neighboring cavities and the effect of flow retardation. ' To this end, 

 three-dimensional cavity-flow theory similar to the lifting-surface theory for sub- 

 cavitating propellers ' has been formulated. However, to date none of the 

 theories has been applied to the actual design of a supercavitating propeller owing 

 to the numerical complexity of the problem. 



As with subcavitating propellers, a supercavitating propeller may be designed 

 in two steps: preliminary or lifting-line design and final or lifting-surface 

 design. The former gives an approximate solution and supplies basic data to the 

 latter. The preliminary design supplies information for the final design concerning 

 load distribution on the blade and preliminary pitch distribution, which forms the 

 basic singularity surface for the final design. The section shape of the blade 

 cavity and the cavity length of a supercavitating cascade model are also computed in 

 the preliminary design. The information is used in the final design as the first 

 approximation. Although this report deals mainly with the final design, we also 

 consider aspects of the preliminary design to help the reader understand the final 

 design more fully. 



The propeller diameter, the blade number and contour, the hub diameter for the 

 given propeller-thrust power coefficient with the given ship speed, propeller revo- 

 lutions per minute (rpm) , and the wake fraction are considered to have been deter- 

 mined before applying the present preliminary and final programs. To ensure that 

 the designed propeller is fully cavitating and that the blades are thick enough, the 

 leading-edge cavity thickness is specified. If the specified cavity thickness near 

 the leading edge does not accommodate a stable cavity of at least 1.5 chord lengths 

 because the cavitation number is too large, then the leading-edge cavity thickness 

 is increased internally to make a long enough cavity for the preliminary program. 



The purpose of the present program is to design a fully cavitating propeller 

 that is efficient, has no face cavitation, is structurally strong, and meets the 

 design requirements. 



As for a subcavitating propeller, the supercavitating propeller is represented 

 by vortex and source distributions. The source strengths are related to the cavity 

 thickness, are not known a priori and are to be obtained by solving related singular 

 integral equations. When the source strengths are known, the supercavitating pro- 

 peller problem is similar to the problem for a subcavitating propeller with thick 

 and wide blades. Thus, many of the computation techniques apply to both 



