Stability – I : Chapter 4

  1. A box-shaped vessel 120m long and 15m wide has alight draft of 4m and load draft of 9.8m in SW. find her light displacement, load displacement and DWT.
Solution :

Area of box shape vessel = (L x B)
= 120m x 15m
Light draft = 4m

Light displacement = (u/w volume) x ( density)
= (L x b x d )x (1.025)
= (120 x 15 x 4) x (1.025)
= 7380 t

Load draft   = 9.8m

So load displacement = (u/w volume) x (1.025)
= ( L x b x d) x (1.025)
= (120 x 15 x 9.8) x (1.025)
= 18081t

Hence, DWT =   (Load displacement  –  Light displacement)
= ( 18081  –  7380 )
= 10, 701t

  1. A box-shaped vessel 100m long and 14m wide is floating in SW at a draft of 7.6m. Her light draft is 3.6 m and load draft 8.5m. Find her present displacement, DWT aboard and DWT available.
Solution:

Area of box shape vessel = (L x B)
= (100m x 14m)

Present draft = 7.6m
Present displacement = (Lx b x d) x (density)
= (100 x 14 x 7.6) x (1.025)
=10906 t
Light draft                = 3.6m

Light displacement = (L x B x D) x(1.025)
= (100 x 14 x 3.6 ) x (1.025)
= 5166t

When Load draft is     = 8.5m

Load displacement = ( L x b x d )x (1.025)
= (100 x 14 x 8.5) x (1.025)
= 12,197.5t

We know that

DWT aboard  =  (present displacement – Light displacement)
=    (10906 t – 5166 t )
= 5740 t

DWT available  = (Load displacement – present displacement)
=   ( 12,197.5 t  – 10,906 t )
= 1291.5t.

About the author

Amit Sharma

Graduated from M.E.R.I. Mumbai (Mumbai University), After a brief sailing founded this website with the idea to bring the maritime education online which must be free and available for all at all times and to find basic solutions that are of extreme importance to a seafarer by our innovative ideas.

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