SHIP STABILITY 503 smaller will be her coefficient. In destroyers, yachts and vessels wneie great speed is required the coefficient may be as small as 45, whereas in the bluff tramp class where speed is a secondary consideration the coefficient is often as great as -85. Between these two extremes the coefficient of fineness is adopted to suit the requirements of the vessel. SHIP STABILITY, Draw a cross section of a ship with a waterlme across it. Mark a spot G to represent the centre of gravity of the ship which is a point where the whole weight of the ship and her contents are conceived to act vertically downwards, Mark a spot B to represent the centre of buoyancy of the ship. It is the point at the centre of the displaced volume of water through which the whole supporting force of the water is conceived to act vertically upwards. It will be the geometrical centre of the figure W L K. w q B* Fig. 25, The downward force at 6 is equal to the upward force at B. They are equal and opposite forces acting in the same vertical line when the ship is at rest. When they are not in the same vertical line something must happen as the ship cannot remain at rest as she wants, auto- matically, to return to her position of equilibrium. In Figure 25 K