C L DUBEY – EXERCISE – 08 (DRY DOCKING)

= 2.925m by stern

16. A vassel of length 84m, displacement 3000t, TPC = 12t, KM = 4.5m, KG = 4.05m, MCTC = 80 TM, CF = 2m abaft midship at a draft of 4m (F) 4.5m (A) is drydocked. Calculate (1) the residual GM in taking blocks all over. (2) her drafts F & A then (3) her draft F&A when she becomes untable.

Solution –

• After taking block allover change in trim = 50cm

P = 50 ⨯ 80/40
= 100 tonnes
GG1 = P ⨯ KM/W
= 100 ⨯ 4.5/3000
= 0.15m

 Residual GM = 0.3m

• Original hd (Hydrostatic draft)  = Aft draft minus correction.

Correction to aft draft = trim ⨯ LCF/LBP
= 0.5 ⨯ 40/84
= 0.238m

Hd = (4.5 – 0.238)m
= 4.262m
Rise = P/ TPC ⨯ 100
= 100/1200
= 0.083m