Miscelleneous

# C L DUBEY – EXERCISE – 09 (GROUNDING)

###### Solution –
• Draft before Grounding = 6.70m, Aft = 8.86m

Trim = 2.16m
Correction to aft draft = 2.16 ⨯ 71/142
= 1.08m
∴ Hydrostatic draft = 7.78m

Draft after grounding = 5.90 m fwd

Trim = 3.4m
Correction to aft draft =   3.4 ⨯ 71/142
∴ Hydrostatic draft = 7.60m
Rise = P/ TPC ⨯ 100
P = (0.18 ⨯ 23.4 ⨯ 100)

= 421.2 tonnes

• Trim before grounding = 2.16m,

Trim after grounding = 3.40m
Change in trim = 1.24m
1.24 = 421.2 ⨯ d/192 ⨯ 100
d = 56.52 m from COF

From AP distance = 71.00 + 56.52 = 127.52m

• GG1 = (P ⨯ KM)/W

= 421.2 ⨯ 8.24/16130
= 0.215m

New GM = 0.765m

FSC = 1372/(16130 – 421.2)
= 0.0873m

GM (fluid) = 0.678m

• Rise of tide required = P/ TPC + P ⨯ d/ MCTC ⨯ d/ LBP

= 421.2/23.4 + 421.2 ⨯ 56.52 ⨯ 56.52/192 ⨯ 142
= 18 + 49.35

= 67.35cm

###### Solution –

Distance of grounding point from COF = 55m
We have P = trim ⨯ MCTC/d
Change in draft = P/TPC + P ⨯ d/MCTC ⨯ d/LBP
So, 80 =   P/18 + P ⨯ 55/130 ⨯ 55/140

Or, P = 360.74

GG1 = (P ⨯ KM)/ W
= 0.125m

Virtual GM   = GM – Virtual loss of GM( GG1)
= 0.475m

Also,
Trim caused = Tc = (P ⨯ d)/ MCTC ⨯ 100
= 1.526m

Ta = 0.796m,
Tf = 0.730m

Rise = P/ TPC ⨯ 100
= 0.200 tonnes 