Behavior of Unusual Ship Forms 



DISCUSSION 



E. V. Lewis 

 Webb Institute of Naval Architecture 

 Glen Cove, Long Island, New York 



This paper presents results of an interesting and important investigation 

 into a possible means of obtaining higher speed in an air-breathing near-surface 

 ship. This ship shows superior resistance characteristics in comparison 

 with other ships at speeds above 35 knots, in both smooth and rough water. The 

 ingenious hydrofoil strut design provides an excellent solution to the problem of 

 stability in a vertical plane, enabling the craft to maintain constant depth below 

 the surface. 



An interesting feature of this hydrofoil semi- submarine is its motions in 

 waves. Its long natural periods of heaving and pitching result in "supercritical" 

 conditions of operation for all head seas. It is only in astern seas that large 

 motions are experienced, and since the periods of encounter are very long, ac- 

 celerations must be low. It thus appears clear that such a craft would be an 

 excellent complement to a more conventional type of surface craft: the former 

 would be able to make high speed in head seas and the latter in astern seas. 

 Operational studies should be made to evaluate the effectiveness of pairs of 

 such ships working together in A.S.W. and other naval missions. 



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