Stability – I : Chapter 6

  1. In a vessel of 8800 tonnes displacement and KG 6.2m, 200 tonnes of cargo was loaded in the lower hold 1.7m above the keel. Find the final KG.
Solution:

Given:-

Weight = 8800t,
Original KG =6.2m,
Cargo loaded = 200t,
KG = 1.7m

Ship’s weight
KG
VM
8800 t 6.2m 54560tm
(+) 200 load 1.7m Final VM  54900 tm

Final W – 9000 t                                               Final VM  54900 tm

So, we can calculate

Final KG = (Final VM/ Final W)
Final KG = (54900 / 9000)
= 6.1m

Here ‘VM’ stands for vertical moments.

  1. 600 tonnes of cargo were discharged from a vessel from the upper 11m above the keel. In the original KG displacement were 6m and 12600 tonnes, calculate the KG.
Solution:-

Given:-
Weight =12600 t
Original KG =6m
Cargo discharged  = 600 t,

Cargo discharge 11 m above the keel

Ship’s weight
KG
VM
12,600t   6m 75,600tm
( -) 600t ( discharge) 11m  (-) 6600tm

Final Weight =12000 t                               Final VM =69000tm

We know that :

Final KG         =        (Final VM / Final Weight)

Final  KG         =          ( 69,000 / 12000)

= 5.75m

  1. In a vessel of 9900 tonnes displacement and KG 4m, a heavy lift of 100 tonnes is loaded on the UD (KG 15m ). Find the final KG.
Solution:
Ship’s weight
KG
VM
12,600t    4m 39,600tm
(+)100 t  load  15m  ( +)1500tm

Final W 10000t                                             Final VM =41000tm

We know that:

Final KG         =        (Final VM / Final Weight)
Final KG        =   ( 41000 / 10000 )
=   4.11m.

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.