Page 217 - statbility for masters and mates

Bilging and permeability 205
Fig. 21.1(b)
weight of water. `X' represents the increase in draft due to bilging. The volume of lost buoyancy (v) is made good by the volumes `y' and `z'.
;v y z
Let `A' be the area of the water-plane before bilging, and let `a' be the
area of the bilged compartment. Then:
or
i.e.
y z Ax ax
v x A a
Increase in draft x v A a
Increase in draft Volume of lost buoyancy Area of intact waterplane
Note. Since the distribution of weight within the vessel has not been altered the KG after bilging will be the same as the KG before bilging.
Example 1
A box-shaped vessel is 50 metres long and is ¯oating on an even keel at 4 metres draft. A compartment amidships is 10 metres long and is empty. Find the increase in draft if this compartment is bilged. See Fig. 21.1(c).
let then
x v l B B A a L l B
B Breadth of the vessel
x 10 B 4
50 B 10 B 40B
40B Increase in draft 1 metre