Page 259 - statbility for masters and mates
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Drydocking and grounding 247
Therefore, or,
where
P l MCTC t P MCTC t
l
Fig. 28.1
P the upthrust at the stern in tonnes,
t the change of trim since entering the drydock in centimetres, and l the distance of the centre of flotation from aft in metres.
Now consider Figure 28.2 which shows a transverse section of the ship during the critical period after she has been inclined to a small angle (y degrees) by a force external to the ship. For the sake of clarity the angle of heel has been magni®ed. The weight of the ship (W) acts downwards through the centre of gravity (G). The force P acts upwards through the keel (K) and is equal to the weight being borne by the blocks. For equilibrium the force of buoyancy must now be (W P) and will act upwards through the initial metacentre (M).
Fig. 28.2
