The results of the irregular wave tests are summarized in Table 2, 

 which presents the average peak- to- peak values of pitch, roll, and heave 

 for the various draft conditions tested. It is apparent from the data in 

 this table that the motions are reduced considerably in the heavy draft 

 corjdition. For example, in a State 6 sea, the heave motion for Condition 4 

 is about 1/10 to 1/20 of the corresponding motions in Condition 1 and the 

 pitch motion is about 1/5. 



SUMMARY 



The test results show that as the draft or displacement of the model 

 increases, the motions in general decrease for a given sea state. Certainly j 

 the motions of the platform increase with increase in sea state for a given 

 draft or displacement. The model tends to roll more in a beam sea than 

 it pitchas in a head sea. The motions in the oblique heading (bow seas or 

 45 deg from the head) were generally less than in the head or beam heading 

 for the same condition. 



REFERENCES 



1. NRL letter 5520-58 REF/cc NRL Problem 501-21, Serial 2215 of 

 10 Mar 1961. 



2. Department of the Navy, Bureau of Yards and Docks, Drawings of Project 

 NBY-2378. 



