A New Appraisal of Strip Theory 



b. For ships C, D, and E: 



"The Influence of Shipform and Length on the Behavior of Destroyer- 

 Type Ships in Head and Beam Seas," by Muntjewerf, International 

 Shipbuilding Progress, Vol. 10, No. 102, February 1963. 



6. The computer program used to calculate the ship motions presented here 

 was written in the Bureau of Ships and is based upon a theoretical method devel- 

 oped by Korvin-Kroukovsky for computing the coupled pitch and heave of a sur- 

 face ship in regular head waves. The step-by-step computational procedure 

 followed by the computer is essentially that presented in Davidson Laboratory 

 Report No. 791, "Guide to Computational Procedure for Analytical Evaluation of 

 Ship Bending Moments in Regular Waves," by Jacobs, Dalzell, and Lalangas 

 dated October 1960. The computer program uses the Prohaska added mass co- 

 efficients with Ursell's free surface corrections and Grim's 1959 damping co- 

 efficients, all published in D. L. Report No. 791. It is recognized that it would 

 be more logical to use Grim's 1959 added mass and damping coefficients or 

 perhaps even more recent data; this was not done for several practical reasons. 

 The Bureau of Ships computer program divides the hull into ten station spaces 

 for the computations. It has been found that the use of a greater number of 

 station spaces has a negligible effect on the computed results. 



NOMENCLATURE 



maximum single amplitude of pitching motion, 



Z maximum single amplitude of heaving motion of ship's center of 

 gravity, 



e phase lead of maximum pitch up measured with respect to the instant 

 when the wave node preceding the wave crest is at the ship's longitu- 

 dinal center of gravity location, 



s phase lead of maximum heave up defined as for pitch phase angle 

 above, 



k regular wave length, 



L waterline length of ship, 



h regular wave amplitude, 



2h regular wave height (twice wave amplitude), 



Ki// lor^itudinal radius of gyration of ship. 



221-249 O - 66 - 25 369 



