Page 108 - statbility for masters and mates

96
Ship Stability for Masters and Mates
Final KG Final moment Final displacement
44 330 6:33 m 7000
GM KM KG
KM 7:33 m; as given
Final KG 6:33 m; as calculated
Ans. Final GM 1.00 m
Note. KM was assumed to be similar value at 6000 tonnes and 7000 tonnes displacement. This is feasible. As can be seen on Figure 6.2, it is possible to have the same KM at two different drafts.
Example 2
A ship of 5000tonnes displacement has KG4.5m, KM5.3m. The following cargo is loaded:
2000 tonnes KG 3:7 m; and 1000 tonnes KG 7:5 m:
Find how much deck cargo (KG 9 m) may now be loaded if the ship is to sail with a minimum GM of 0.3 m.
Let `x' tonnes of deck cargo be loaded, so that the vessel sails with
GM 0.3m.
Final KM Final GM Final KG
Final KG ; 5
40 000 5x 2600 x
5:3 m 0:3 m 5:0 m
Final moment Final displacement
37 400 9x 8000 x 37 400 9x
4x
650 tonnes
Ans. Maximum to load 650 tonnes
5:0 m
Moment about the keel
22 500 7400 7500
Weight
5000
2000
1000
KG
4.5 3.7 7.5
x 9.0 9x 8000 x 37400 9x