Miscelleneous

C L DUBEY – EXERCISE – 08 (DRY DOCKING)

  Fwd         Aft
Drafts 9.42m      10.88m
DWA -0.09m     -0.09m
  9.33m    10.79m
    -0.047m +0.043m
  9.283m 10.833

Therefore, Trim now = 1.55m
Now P = (trim ⨯ MCTC)/d
= 155 ⨯ 252.76/112.5
= 348.25

MCTC in 1.020 = 252.76

We know that –
GG1 = P ⨯ KM/W
= 0.185m,

Old GM = (KM – KG)
= (10.2 – 9.4)m
= 0.8m

Virtual GM = (0.8 – 0.185) m
                      = 0.615m
  1. A vessel of displacement 6220t, length 144m, CF 2m abaft midships, KM 6.9m, MCTC = 150, TPC = 17t, KG 6.2m at a draft of F 4.10m, A 6.20m, is floating in a dry dock were the depth of water is 7.0m above the top of the blocks. Calculate her virtual GM (i) when the level is lowered by 1.5m, (ii) when the water level is lowered a further 1 m.
Solution –

Draft fwd = 4.10m, draft aft = 6.20m,
Trim = 2.10m

Corn to aft draft = 2.10 ⨯ 70/144
= 1.021m

Hydrostatic draft = (6.20 – 1.021)m
= 5.179m

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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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