Stability – I : Chapter 4

4. A double bottom tank 20m x 10.5m x 1.0m has a block a coefficient of 0.82. Calculate how much fuel oil of RD 0.9, it can hold .

Solution :

Given : – (L x B x H) of double bottom tank =( 20 x 10 .5 x 1)
Cb = 0.82 , RD = 0.95

We know that:

Cb   = (volume of tank) /( L x B x depth)
0.82 = (volume of tank) /(20 x 10.5×1)
volume of tank = 0.82 x ( 20 x 10.5x 1)
= 172.2 m³

Weight of oil can be calculated as :-  (volume of tank) x(density)
= (172.2 x 0.95)
= 163.59 t

5. A ship floating in SW at a draft of 8m is 110m long and 14m wide at the water line . If her block coefficient is 0,72, find her displacement. If her load displacement is 12000 t, find the DWT available .

Solution:

Given: – (L x B)  = 110m x 14m,
Present draft = 8m
Cb = 0.72

Load displacement = 12000 t ,

We know that :-

Cb = (u/w volume ) / (Lx B x D)
0.72 = (u/w volume) / (110 x 14 x8)

u/w volume  =  0.72  x ( 110 x 14 x 8 )
= 8870.4 t

DWT available   = (Load displacement  – present displacement)
= (12000 – 8870.4)
= 3129.6t.