C L DUBEY – EXERCISE – 08 (DRY DOCKING)

Tf = 0.532m

	Fwd	Aft
Draft	3.72m	5.70m
	-0.122m	-0.122m
	+ 0.532	-0.577m
	4.130m	5.000m

14. A box shaped vessel 80 × 16m at draft of 3m (F), 4m (A) KG = 4.2m is drydocked. Calculate the residual GM on taking blocks F & Aft. KG = 4.2m.

Solution –

In this question KM_T,MCTC & TPC is not given
Since this is a box shaped vessel both can be found.
MCTC = W ⨯ GM_L/100 ⨯ LBP
TPC = A/100 ⨯ density of water displaced

KM_T = KB + BM
BM_T = b²/12D
= 16 ⨯ 16/12 ⨯ 3.5
= 6.095
KM = (6.095 + 1.75)m
= 7.845m

For TPC
Area of water plane = (80 ⨯ 16)m²
                                           = 1280m²
TPC = 1280/100 ⨯ 1.025
        = 13.12 tonnes / cm

For MCTC
GM_L = (KM_L – KG)
& KM_L = KB + BM_L
BM_L=   I/V
I = lb³/12 for long   bl³/12

V = volume = l ⨯ b ⨯ d
= b ⨯ l³/12 ⨯ (l ⨯ b ⨯ d)
= l²/12d
= 80 ⨯ 80/12 ⨯ 3.5
= 152.38m

KB = depth/2
= 3.5/2
= 1.75m

KM_L = (1.75 + 152.38)m
= 154.13m