Behavior of Unusual Ship Forms 



Figure 13; critical speed zones correspond to severe motions, wet decks, and 

 slamming while sub and supercritical zones correspond to very moderate mo- 

 tions and intermediate zones to motions intermediate between the two extreme 

 conditions. A complete analysis of this figure is given in Mandel's paper. It is 

 of interest for our purposes to examine the major differences in zone extent pre- 

 dicted for these unusual ships and, further, to remark that these results of an 

 idealized analysis are supported to a large extent by the available regular sea 

 data. The destroyer is seen to be sub or supercritical in all following seas, 

 while the Semi-Submarine enjoys these conditions for all ahead seas and following 



ill 



50 4 30 20 



— ASTERN SEAS 



10 10 



SHIP SPEED (KNOTS) 



20 30 40 



AHEAD SEAS — 





CRITICAL ZONE 



INTERMEDIATE ZONE 



SUB OR SUPER CRITICAL ZONE 



HEAVE 



Fig. 13 - Operation zones in rough seas for several unusual ships 



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