Page 249 - statbility for masters and mates

Summer freeboard DWA Min. permissible freeboard Present freeboard Mean sinkage Cargo to load Cargo to load
GG1
; Rise of G Present GM (8.6 7.7) GM on departure
and ship has a sag of 0.04 m.
True mean draft 237
1:020 m
0:064 m
0:956 m
1:060 m
0:104 m or 10.4 cm
Sinkage TPCdw 10:4 19:8 205:92 tonnes
w d 205:92 10 7:7 473:62 W w 12000 205:92 12205:92
0:039 m 0:900 m 0:861 m
Exercise 25
1 The minimum permissible freeboard for a ship is at a true mean draft of 7.3m. The present draft is 6.2m F and 8.2m A. TPC 10. The centre of ¯otation is 3 m aft of amidships. Length of the ship 90 m. Find how much more cargo may be loaded.
2 A ship has a load salt water displacement of 12 000 tonnes, load draft in salt water 8.5 m, length 120 m, TPC 15 tonnes, and centre of ¯otation 2 m aft of amidships. The ship is at present ¯oating in dock water of density 1015 kg per cu.m at drafts of 7.2m F and 9.2m A. Find the cargo which must yet be loaded to bring the ship to the maximum permissible draft.
3 Find the weight of the cargo the ship in Question 2 could have loaded had the centre of ¯otation been 3 m forward of amidships instead of 2 m aft.
4 A ship is ¯oating in dock water of relative density 1.020. The present displacement is 10 000 tonnes, KG 6.02 m, KM 6.92 m. Present drafts are F 12.65 m, A 13.25 m. Present freeboard 1.05 m. Summer draft 13.10 m and Summer freeboard is 1.01m. FWA 150mm. TPC 21. Assuming that the KM is constant ®nd the amount of cargo (KG 10.0 m) which can be loaded for the ship to sail at the load Summer draft. Find also the amount of the
hog or sag and the initial metacentric height on departure.