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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 11.1(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 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 w1 Kg1 and
(a)
(b)
Fig. 11.1
