Page 172 - statbility for masters and mates

160 Ship Stability for Masters and Mates
What is the minimum amount of water ballast required to be taken into the forepeak tank (centre of gravity 60m forward of the centre of ¯otation) to reduce the draft aft to 6.5 metres? Find also the ®nal draft forward.
20 A ship leaves port with drafts 7.6 m F and 7.9 m A. 400 tonnes of bunkers are burned from a space whose centre of gravity is 15 m forward of the centre of ¯otation, which is amidships. TPC 20 tonnes. MCT 1 cm 300 tonnes m. Find the minimum amount of water which must be run into the forepeak tank (centre of gravity 60 m forward of the centre of ¯otation) in order to bring the draft aft to the maximum of 7.7 m. Find also the ®nal draft forward.
21 A ship 100 m long has MCT 1 cm 300 tonnes-m requires 1200 tonnes of cargo to complete loading and is at present ¯oating at drafts of 5.7 m F and 6.4 m A. She loads 600 tonnes of cargo in a space whose centre of gravity is 3m forward of amidships. The drafts are then 6.03m F and 6.67 m A. The remainder of the cargo is to be loaded in No. 1 hold (centre of gravity 43 m forward of amidships) and in No. 4 hold (centre of gravity 37 m aft of amidships). Find the amount which must be loaded in each hold to ensure that the draft aft will not exceed 6.8 metres. LCF is at amidships.
22 A ship 100 metres long is ¯oating in salt water at drafts 5.7 m F and 8 m A. The centre of ¯otation is 2m aft of amidships. Find the amount of water to run into the forepeak tank (centre of gravity 48 m forward of amidships) to bring the draft aft to 7.9m. TPC 30 tonnes. MCT 1 cm 300 tonnes m.
23 A ship 140 m long arrives off a port with drafts 5.7 m F and 6.3 m A. The centre of ¯otation is 3m aft of amidships. TPC 30 tonnes. MCT 1 cm 420 tonnes m. It is required to reduce the draft aft to 6.2 m by running water into the forepeak tank (centre of gravity 67 m forward of amidships). Find the minimum amount of water to load and also give the ®nal draft forward.
Using change of trim to ®nd GMv
24 A ship 150 m long is ¯oating upright on an even keel. When a weight
already on board is shifted aft, it causes the ship's centre of gravity to shift 0.2 m horizontally and the trim to change by 0.15 m. Find the longitudinal metacentric height.
25 A ship of 5000 tonnes displacement is 120 m long and ¯oats upright on an even keel. When a mass of 40 tonnes, already on board, is shifted 25 m forward horizontally, it causes the trim to change by 0.1m. Find the longitudinal metacentric height.
26 A ship is 130 m LBP and is loaded ready for departure as shown in the table below. From her Hydrostatic Curves at 8 m even-keel draft in salt water it is found that: MCTC is 150 tm/cm. LCF is 2.5 m forward e , W is 12 795 tonnes and LCB is 2 m for'd e . Calculate the ®nal end drafts for