Savitsky 3 Ropev 3 and Benen 



Hydrodynamic Impact ( 77__) = 0. 4 g in state 3 head sea) 



CG avg '. 



Two possible options are available for a 20° deadrise hull. 



(1) 



(2) 



B 



Option (1) satisfies all the hydrodynamic and operational 

 requirements while Option (2) does not satisfy the basic metacentric 

 height requirement. The 116 ft. boat lenght of Option (l) was con- 

 sidered excessive when compared with space requirements for internal 

 arrangements. This excessive length would increase the cost of the 

 boat without materially improving its performance. 



As a compromise design, a double chine hull having a length 

 of 92 ft. was selected. A mid-length section through this hull is 

 shown in Figure 8. The inner chine beam is 14 ft. and the outer chine 

 beam is 15. 7 ft. In the static or low speed condition, the wetted 

 beam is 15. 7 ft. so that the metacentric stability requirement is sa- 

 tisfied by the combination of L = 92 ft. and b = 15. 7 ft. At the 45- 

 knot condition, the flow separates from the lower chine so that the 

 92 ft. long hull has an effective beam of 14 ft. This satisfies the 

 high-speed impact requirements. The metacentric stability of the 

 craft is now satisfied by considering the additional roll stabilizing mo- 

 ments developed by the dynamic loads generated at high speeds. 



In summary then, the following basic hull dimensions and 

 loadings are selected for preliminary design 



92 ft. 



432 



