1 12 



THEORY OF SEAKEEPING 



Cross-Sectional Forms 



Direction of Motion 

 Axis of Rotation 



l-'i?v 



^^ 





Za. H- 



2a 



^^ 





t ^— -^>^^ 



*H ^a 



^ 



= 1 (circle) 



Plate 



Square 



= 2 



-r=5 



— = 10 



— = O.Oo 



- 0.1 



— = (1.25 



Hydrodynamic Mass 

 per Unit Length 



I'J 



m"= nga' 



HI 



=,nQa' 



I'l 



^^ 71 pa' 



121 



=■ 1.7 71 pu^ 



[2] 



1.98 n pa* 



12] 



2.23 .-tpa^ 



[2] 



121 



1.30 7iga^ 



121 



X.-nnga^ 



121 



XAAnga- 



[51 



l.iil 77 g a" 



(51 



\.~ln ga'^ 



15] 



2. 19/7 £.0- 



Inertia Coefficient 



)n"circle 



7"=0 



!.■ 



1.98 



2.23 



1.51 



1.36 



1.21 



1.14 



1.61 



1.72 



2.19 



Referred to 

 Circle with 

 Radius a 



Hydrodynamic Uondnt 



of Inertia 



per Unit Length 



//; 



= 0.1257te(a*-**) 



= 0.125nea« 



11] 



= 0.15 7iet« 



1^1 



= o.i57iefe« 



in 



D 



Inertia Coefficient 

 for Rotation 

 J" 



./"plate 



a 



= 0.147 7re6« 



lij 



13, il 



0.234 .T pa* 



151 



' =0.\57iQa* 



= 0.147 Tipa* 



I5J 



= 0.3\7iQa* 



151 



= 0.4 7T e a* 



151 



= 0.69 77 pa* 



151 



1.2 



Referred to 

 Plate of 

 Width 26 



1.18 



1.872 



M.2 



Referred to 

 Plate of 

 Width la 



1.18, 



2.4 



3.2 



Referred to 

 Plate of 

 Width 2a 



o.o 



Fig. 4 Tabulation of hydrodynamic masses, hydrodynamic moments of inertia, and inertia coefficients as calculated by |1| Lamb, 

 I2| Lewis, [3] Proudman, [4] Weinblum, [5] Wendel, [61 determined experimentally (electrical analog) by Koch (from Wendel, 



1950) 



primary cause of damping. The standing-wave system circular cylinder (Ursell, 1949b, 1953, 1955).^ The 1 



is very complex and the mathematical solution for the 7 Three-dimensional solutions for special mathematical ship, 



added mass has so far been obtained only for a floating forms by Haskind and Hanaoka will be discussed in Section 6. 



