Stability – I : Chapter 3

  1. A rectangular barge of 10 m long and 5m wide, floating in SW at a draft of 3m, is being lifted out of the water by a heavy-lift crane. Find the load on the crane when the draft has reduced to 1m.
    Solution:

Area of rectangular barge = ( L x B)
= 10m x 5m,
RD = 1.025

Mass when draft 3m = (u/w volume at 3m) x (density)
= (10 x 5 x 3) x (1.025)
= 153.75t.

Mass after being lifted by the heavy crane =(u/w volume at 1m depth )x (density)
= (10 x5 x 1) x (1.0250
= 51.25 t

Hence ,Load taken by the crane = (153.75 – 51.25)
=  102.5 t

  1. A rectangular box 2.4 m long, 1.2m wide and 0.8m high, floats in water of RD 1.012m at an even keel draft of 0.2m. find maximum mass of SW that can be poured in to it without sinking it.
Solution :

Given :
L = 2.4m, B = 1.2m, H = 0.8m
RD =  1.012 , Depth = 0.2m

Mass of rectangular box = (L x B x H )x (1.012)
= (2.4 x 1.2 x 0.8) x (1.012)
= 2.33t

Mass of box even keel when draft  is 0.2m
= (2.4 x 1.2 x 0.2) x(1.012)
= 0.583

Hence, Salt water that  can poured  is (2.33 – 0.58)
= 1.75 t.

  1. A box – shaped vessel of 18450 t displacement in 150m long and 20 m wide. Find its draft in SW.
     Solution:

We know that:

Displacement =   (U/w volume)x  (density)
18450  =    ( 150 x 20x D) x (1.025)
D       =    ( 18450 ) / ( 150 x 20 x 1.025)
Draft  = 6m

  1. A box-shaped vessel 120m long and 15m wide is floating in DW of RD 1.005 at a draft of 5m. if her maximum permissible draft in SW in 6m , find how much cargo she can now load .
Solution:

Area of box shape vessel = (Lx b)
= 120 x 15m,
RD = 1.005, Draft =5m
Mass     = (u/w volume ) x (density)
= (120 x 15 x 5) x (1.005)
= 9045t .

Maximum cargo she can load = (120 x 15 x 6) x (1.025)= 11070 t

Cargo can be load = (11070 – 9045)
= 2025t.

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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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