Tham khảo tài liệu 'ship stability for masters and mates 5 episode 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Chapter 11 Final KG When a ship is completed by the builders certain written stability information must be handed over to the shipowner with the ship. Details of the information required are contained in the load line Rules parts of which are reproduced in Appendix I of this book. The information includes details of the ship s Lightweight the Lightweight VCG and LCG and also the positions of the centres of gravity of cargo and bunker spaces. This gives an initial condition from which the displacement and KG for any condition of loading may be calculated. The nal KG is found by taking the moments of the weights loaded or discharged about the keel. For convenience when taking the moments consider the ship to be on her beam ends. In Figure a KG represents the original height of the centre of gravity above the keel and W represents the original displacement. The original moment about the keel is therefore W X KG. Now load a weight w1 with its centre of gravity at g1 and discharge w2 from g2. This will produce moments about the keel of w1X Kg1 and w w w w a b Fig. Final KG 95 w2 X Kg2 in directions indicated in the figure. The final moment about the keel will be equal to the original moment plus the moment of the weight added minus the moment of the weight discharged. But the final moment must also be equal to the final displacement multiplied by the final KG as shown in Figure b . . Final moment Final KG X Final displacement or Final moment Final KG ------ Final displacement Example 1 A ship of 6000 tonnes displacement has KG 6 m and KM m. The following cargo is loaded 1000 tonnes KG m 500 tonnes KG m 750 tonnes KG m The following is then discharged 450 tonnes of cargo KG m and 800 tonnes of cargo KG m Find the final GM. Weight KG Moment about the keel 6000 36 000 1000 2500 500 1750 750 6750 8250 47 000 -450 -270 -800 -2400 7000 44 330 96 Ship Stability for Masters and Mates Final KG Final moment Final
