C L DUBEY – EXERCISE – 11 (Grain Stability)

• GM = 0.776m

Therefore, condition 1 satisfied

• Angle of heel = 12⁰ = Marginal.

Heel	Ordinate	SM	Product
0	0.0	1	0
10	0.15	4	0.60
20	0.33	2	0.66
30	0.645	4	2.28
40	0.610	1	0.610
			4.45

Area = 10/3 ⨯ 4.45/57.3
= 0.259m radian

Area of triangle = 0.5 ⨯ 12 ⨯ 0.19/57.3
= 0.0199m radian

Area of trapezium = 0.5 ⨯ (0.19 + 0.16) ⨯ 28/57.3
= 0.085 m radian

Residual area = 0.16m radian ˃ 0.075
Therefore, condition 3 satisfied.

Hence, vessel satisfy intact stability requirement for grain cargo or grain loading criteria.

Q2. The values of GZ of a vessel at different angles of heel are as follows:

Heel (0)	0	5	12	20	30	40	60	75
GZ (m)	0.0	0.188	0.449	0.764	1.227	1.551	1.713	1.298

The heeling arm at 0⁰ = 0.275 metres. The angle of flooding is 400 and maximum difference between the righting arm and heeling arm occurs at an angle greater than 400. Verify whether the vessel satisfies the intact stability requirements for a cargo ship carrying grain in bulk.

Solution –

Given λ₀ = 0.275, λ₄₀ = 0.22