A vessel displaces 4500 t of FW at a certain draft . Find her displacement at the same draft in water of RD 1.020 .

Solution:

Displacement (W) = 4500t,

Displacement = (u/w volume ) x (density)
= (L x B x draft) x 1.025

Draft = W / (L x B x 1.025) m

Let W1 be the displacement at RD 1.020

So W1 =( L x B x d )x (1.020)
d = (W1 / (Lx B x 1.020)

according to question,  Draft  =  d

W /( L x B x 1.025)  =  W1 /( L x B x 1.020)
W1 = (4500 x 1.020) / 1.025
= 4478.04t.