Murthy 



longitudinal planes of the hulls are to be taken in their instantaneous 

 position when evaluating the surface integral for the pressure force. 



The pressure of water may be assumed to be an even function 

 of y and therefore of y 1 



= Pc 



o+ 



o- 



and 



= Pc 



O- 



o+ 



and in integrating over S 1 and S we may combine the integrals 



over 



and 



s i + s 2 



o+ o- 



S l + S 2 ; 

 o- o+ 



where the hull functions are the same for each group. The j -compo- 

 nent is however, of a different sign in each group and therefore the 

 lateral force vanishes. 



We thus have 



X, 



H 



J/K P+ "^ +P_ "^/ C ° 



/ + a h i . a h 2 \ 

 \p T^r +p ~c^/ 8m 



sd 



dx'dz 1 



= 



H 



H 



■ ~K 



+ S h l 



a h 2 



+ P -g— -)C0.I 



186 



