Miscelleneous

C L DUBEY – EXERCISE – 08 (DRY DOCKING)

= 5.415m
  1. A vessel about to dry dockn is in the following condition :
draft : For’d 6.10m, Aft 6.70m
KMₒ = 7.20m, KGₒ = 6.8m
MCTC = 155 tm, TPC = 22t,  LCF = 80m for’d of AP
Length = 180m,  Disp = 11000 tonnes
Find : (a) GM of the vessel at critical instant
(B)The righting moment of 1° heel
(c)The draft For’d and at the critical instant.
Solution –

Question same as Q. No. – 8

  1. A vessel with length of 185m, displacement of 29000 is floting in a graving dock with a depth of 10m at drafts F 8.00 and A 9.38m. KM = 11.50m, KG = 10.95m, MCTC = 410 t/m, TPC = 29.6, LCF = 89.5m. find the effective GM and draft fore and aft of the vessel after the water level has dropped by 1.25m.
Solution –

After level dropped by 1.25m,
New water Level = (10 – 1.25) m
= 8.75m

Correction to aft draft = (1.38 ⨯ 89.5)/ 185
= 0.668m

(hydrostatic draft ) Hd = 8.712m
Clearly since level of water 8.75m ˃ Hd 8.712m

It means stern has taken to the block and fwd end is still afloat.
Reduction in aft draft = 0.63m
Or, 63 =    P/29.6 + P ⨯ 89.5/4100 ⨯ 89.5/185
Or, P = 451.96 tonnes

We know that –
GG1 = P ⨯ KM/ W
= 451.96 ⨯ 11.50/29000
= 0.179m

Therefore, GM = 0.371m
Trim caused = Tc = 451.96 ⨯ 89.5/410 ⨯ 100
= 0.986m

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Manish Mayank

Graduated from M.E.R.I. (Mumbai). A cool, calm, composed and the brain behind the development of the database. The strong will to contribute in maritime education and to present it in completely different and innovative way is his source of inspiration.

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