International Shipbuilding Progress

Ship model correlation analyses were carried out for six sister ships according to a method, which differs in many respects from methods in general use. The results appear in the form of differences between model and ship wake, and as allowances on ship resistance derived by “three-dimensional extrapolation” from model results. The wake differences agree well with values predicted on theoretical grounds, and the dCT-values are more reasonable than those derived for the same vessels by other methods of analysis.

Polynomial representations and damping coefficients for the Series 60 Block .60, .70 and .80 hull forms are presented. Several polynomials are given, ranging from 48 to 140 terms and providing varying degrees of accuracy as analytic representations of the hull forms. Damping coefficients based upon these polynomials are presented, for various frequencies and Froude numbers, and compared with experimental data. The agreement between experimental and theoretical coefficients is generally good.

Stresses in symplified and more realistic models of propeller blades have been determined according to the Moiré method. The results thereof are compared with some methods of stress calculation in propeller blades.