Stability – I : Chapter 4

6. A vessel of 14000t displacement is 160m long and 20m wide at the water line . If she is floating in SW at a draft of 6.1m, find her block coefficient.

Solution:

Given : – W = 14000 t ,
(L x B) of waterline = (160m x 20m),
Present draft = 6.1m

We know that :

Weight = (u/w volume )x (density of displaced  water)
14000   = (u/w volume) x 1.025
u/w volume   =  14000/ 1.025
= 13658.536 t

We know that:-

Cb   =   (u/w volume )/( Lx B x D)
Cb   =   13658.536 /(160 x 20 x6.1)
= 0.699m
= 0.7m

7. A box-shaped vessel 18m x 5m x2m floats in SW at a draft of 1.4m. Calculate her RB %.

Solution :

Given :- (L x  B x H) of box shape vessel  =(18m x 5m x 2m), Present draft = 6.1m

We know that :-

RB % =  (Above water volume )/(total volume ) x 100
Total volume can be calculated as = (L x B x D)
= 18 x 5x 2m
= 180m³ 

U/w volume = (L x B x present draft)
= 18 x 5 x 1.4
= 126m³ 

Hence, Above water volume = (180 – 126)
= 54m3

RB % = (Above water volume) / (total volume ) x 100
Hence, RB % = (543/180 x 100)
=  30%