Stability – I : Chapter 4

  1. 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%

8. A box –shaped of 2000t displacement is 50m x 10m x 7m. Calculate her RB% in FW
Solution :

Given :- W = 2000t,

 (L x B x H) of box shaped vessel = (50m x 10m x 7m)
 Total volume = 3500m3 
W = ( u/w volume) x (density)
2000 = (u/w volume) x (1.00)
 u/w volume = 2000 m3

Above water volume = (Total volume) – (u/w volume )
                                       = (3500 – 2000)
                                       =  1500 m3                                                      

RB % = (Above water volume) / (total volume ) x 100
RB % = (1500 /3500)x 100
         = 42.857%

9. The TPC of a ship in SW is 30. Calculate her TPC in FW and in DW of RD1.018.
Solution:

We know that:-
TPC   =   (A / 100) x (density)
30   =      (A / 100) x (1.025)
A =    (30 x 100)/ 1.025
A =  2926.83 m2

TPC in FW can be determined as    = ( 2926.83/ 100)x(1)
=29.268  t/cm.

TPC in DW can be determined as  = (2926.83 / 100) x(1.018)
= 29.79 t/cm.

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.

5 Comments

  • many questions have wrong answers in various exercises,,at least book ke end me answers ko chk kar lete…anyways thanks for this website

  • many questions have wrong answers in various exercises,,at least book ke end me answers ko chk kar lete…

  • what is the draft of a box shape steel (L=4 meters , B= 4 meters , Depth = 0.60 meters)
    floating in a salt water density 1.028 and the total weight of the steel box with steel on top of it is 1500 kg

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