Manchester Memoirs, Vol. xlvii. (1903), No. IJJ. 



Hence 



.til . . nl ^ 

 sin - + Sinn — 

 2 2 



I + 



. , nl nl , nl . ttl 



Sinn cos— + cosh— sin — 



22 22 



(2) 



/here 



/.= 



27i'BAdL^ 2IVAL . . , 

 ;rT TT '■= maximum statical stress, 



giving a value for / in terms of/,. 



Substituting this value in the expression for n we get 



2 V \2dE0j 



(3) 



Hence, if it is required to estimate the maximum dyna- 

 mical stress induced in a vessel of this class designed so 

 that the greatest statical stress = 10 tons Q" we get from 



equation (3) -^ = ri4, where the maximum possible 



relative velocity of the waves to the vessel is taken as 

 88 feet per second. This high value for the velocity is 

 taken in order to be on the safe side, inasmuch as waves 

 whose velocity is as great as 50 feet per second* are met 



*Abercromby [Phil. Mag., Vol. 25, 1888), measures the length and 

 velocity of ocean waves and gives a velocity of 28-5 ft. per second, with a 

 wave-length of 358 feet and a height of 26 feet. 

 Rankine, Civil Eiigiiieei-iiig — 



Max. wave length = 560 feet. 



,, velocity = 53 feet per sec. 



,, height =43 feet. 



Lamb, Hydrodynamics, p. 377. Quotes Airey 



