HYDRODYNAMIC DESIGN OF PROPELLERS WITH UNCONVENTIONAL GEOMETRY

The paper defines tip fin propellers as propellers with large degress of rake and skew in the tip region. To examine whether such propellers of unconventional geometry are more efficient than normal propellers, lifting line theory is applied with a curved lifting line. Criteria for maximum efficiency are established by blade element theory and by Munk's displacement theory, and calculations indicate that an increase in efficiency can be obtained for most propeller loadings. By a series of calculations, guidelines for the design of tip fin propellers are developed.