3 

 Hydrodynamio Design of an S Semisubmerged Ship 



DISCUSSION 



Edmund P. Lover 



Admiralty Experiment Works 

 Haslar 3 Gosport, Hants 3 U.K. 



I have a point to make concerning this most interesting paper, 

 and a question to ask. 



Firstly, in Figure 3 of the paper a comparison is made bet- 

 ween the S form and conventional ships. I would like to make the 

 point that the "hull efficiency" WV/P 77 conventional monohulls can be 

 improved significantly above that shown by increasing the length to 

 displacement ratio. These longer vessels would also have improved 

 seakeeping characteristics as well as the Froude number of cross- 

 over above which the S shows to advantage. 



My question is this. Was any simulation made during the 

 model experiments of an emergency crash situation and, if so, did 

 this exhibit any problems with maintenance of trim ? 



REPLY TO DISCUSSION 



Thomas G. Lang 



Naval Undersea Research and Development Center 

 San Diego 3 California^ U.S.A. 



I agree with your comment of reduced drag for the larger 

 length-beam ratio monohulls designed for higher speeds. In the non- 

 dimensional graph of hull efficiency, this effect is already included to 

 a certain extent since the line for monohulls represents the maximum 

 value of existing monohulls wherein the higher-speed monohulls al- 

 ready have a larger length -beam ratio. Thus, the monohull line re- 

 presents the best of the known data, so the majority of monohulls will 

 lie below that line as far as efficiency is concerned. 



Regarding the question of a crash situation, the radio-con - 



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