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(Block 20 continued) 



When a wave crest touches the ship surface, the ray exactly follows 

 the ship surface. When the wave crest is nearly perpendicular to the 

 ship surface the ray is reflected many times as it propagates along the 

 ship surface. Many rays of reflected elementary waves intersect each 

 other. The envelope to the first reflected rays forms a line like a 

 shock front which borders the area of large waves or breaking waves near 

 the ship. 



For the Wigley hull, ray paths, wave phases, and directions of 

 elementary waves are computed by the ray theory and a method of computing 

 wave resistance is developed. The wave phase is compared with that of 

 linear theory as a function of ship-beam length ratio to identify the 

 advancement of the bow wave phase which influences the design of bow 

 bulbs. The wave resistance of the Wigley hull is computed using the 

 amplitude function from Michell's then ship theory and compared with 

 values of Michell's wave resistance. The total wave resistance has the 

 phase of hump and hollow shifted considerably. 



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