Sec. 5y.3 



APPENnACE-RESISTANCE CALCULATIONS 



289 



TABLE 55.a — Percentage Increases in Effective Power P^ to be Expected on Trials of Three Types of Ship 

 The source of these data is given in the accompanying text. 



66.9, to make a quick estimate of probable 

 appendage drag before the appendages are 

 designed or perhaps even before the ship lines are 

 drawn. Such an estimate is possible only by 

 knowing (or deciding) what appendages are 

 involved and the type of ship to which they are 



to be fitted. The basis for estimate is then a 

 percentage of the bare-hull resistance or effective 

 power, based upon systematic data derived 

 largely from model tests. 



A few percentages of this kind, including other 

 percentages as well, are given by W. P. A. van 



TABLE 55. b — Percentage Decreases When Six Series op Appendages Are Removed in Succession from a 



Cruiser Model 

 The values listed are percentages of the total bare-hull resistance of the model at the speed-length quotients given. 

 The data are taken from test's of TMB model 3836. 



TABLE 55.C — Percentage Increases over Bare-Hull Resistance for All Customary 

 Appendages, According to P. Mandel 



Speed-length quotient, T, = V/y/L 

 Froude number, F„ = V/\/gL 

 Large, fast, quadruple-screw ships 

 Small, fast, twin-screw ships 

 Small, medium-speed, twin-screw ships 

 Large, medium-speed, twin-screw ships 

 All single-screw ships 



