0.01 

 0.05 



























































99.99 























































99.9 





















































/ 





0.1 

















































^ 



/ 





99.8 















































/ 



/ 









99.5 













































/ 



/ 

































a Fractiles taken from Table 9 















/ 





















































^ 

















! 



























































* 































/ 



/ 



/ 





















80 b 



























f 



/ 



/ 



















































/ 



/^ 





















































/ 



/ 



































S 50 



1 





















/ 



































- 40 ■" 





















/ 







































k '" 

















y 

















































/ 



/ 



/ 



> 















































y 



/ 











































































































9S 

 99 























































- 1 



0.003 0.005 0.01 0.02 0.05 0.10 0.20 0.50 1.0 



Variation in Pitcli Acceleration, Radians/sec^ Double Amplitude 



Figure 8 - Long-Term Cumulative Distribution of Pitch Acceleration 

 for Wartime Service, North Atlantic Ocean 



This log-normal distribution is computed on the basis of the data represented by the plotted points and it cor- 

 responds to the following parameters: 



Mean value of log-, (pitch acceleration in rad/sec ) = 2.4314 

 Standard deviation of log,, (pitch acceleration in rad/sec ) = 0.4895 



2 

 It is probably valid up to 0.80 rad/sec'. 



waves having the largest magnitudes) will be 1.416 sfE. The most probable magnitude of the 

 largest of 50 variations will be 2.01 \[E. The most probable magnitude of the largest of 500 

 variations will be 2.509 >/F. The most probable magnitude of the largest of /V variations will 

 be (constant) v'^ where the value of the constant is given in Table 7. For large values of A', 

 the constant is approximately equal to \j\-o%^ N. 



The values of E corresponding to various combinations of sea condition, ship speed, 

 and heading are given in Tables 2 through 6. 

 PREDICTION OF EXTREME VALUES 



It may be desired to estimate the largest value of ship motions or hull girder stress 



22 



