inclined to an angle 0, intersect the center line at m, the metacentre which means"change point". If M is above G(the centre of gravity of the ship and its contents), the vessel is in stable equilibrium, When M concides with G, there is neutral equilibrium. When M is below G, the forces of weight and buoyancy tend to increase the angle of inclination, and the equilibrium is unstable The distance Gm is termed the metacentric height and the distance gz. measured from g perpendicular to the vertical through B, is termed the righting level or Gz value. Weight and buoyancy are equal and act through and B, respectively, to produce a moment(tendency to produce a heeling motion )AGZ, where A is the displacement or weight in tons Stability at small angles, known as initial stability, depends upon the metacentric height GM. At large angle, the value of Gz affords a direct measure of stability, and it is common practice to prepare cross-curves of stability, from which a curve of Gz can be obtained for any particular draft and displacement Transverse stability should be adequate to cover possible losses in stability that may arise from flooding, partially filled tanks, and the upward thrust of the ground or from the keelblock when the vessel touches the bottom on being dry-docked The case of longitudinal stability, or trim, is illustrated in Figure3. There is a direct analogy ith the case of transverse stability. When a weight originally on board at position A is moved a distance d, to position B, the new waterline WILI intersects the original waterline WL at center of flotation(the centre of gravity of the water plane area WL), the new centre of buoyancy is B, and the new centre of gravity is G For a small angle of trim, signified by the greek letter theta( e) (a+f)/L wd=△GM1(a+f)/L nolton B tin i y M hostile trin Isx ++1 Changes in stern trim is x-y Fig 3 Longitudinal section of float ship showing change in stern trim as deck load w was shifted from position A to position B(see text Thus if (a+f)=l inch=1/12 foot, wd=AGM/12L and this presents the moment to change trim one inch The inclining experiment A simple test called the inkling experiment provides a direct method of determining GM, the metacentric height, in any particular condition of loading from which the designer can deduceinclined to an angle 0,intersect the center line at M, the metacentre, which means “change point”. If M is above G (the centre of gravity of the ship and its contents),the vessel is in stable equilibrium, When M concides with G, there is neutral equilibrium. When M is below G, the forces of weight and buoyancy tend to increase the angle of inclination, and the equilibrium is unstable. The distance GM is termed the metacentric height and the distance GZ, measured from G perpendicular to the vertical through B, is termed the righting level or GZ value. Weight and buoyancy are equal and act through G and B, respectively, to produce a moment (tendency to produce a heeling motion) △GZ, where △ is the displacement or weight in tons. Stability at small angles, known as initial stability, depends upon the metacentric height GM. At large angle, the value of GZ affords a direct measure of stability, and it is common practice to prepare cross-curves of stability, from which a curve of GZ can be obtained for any particular draft and displacement. Transverse stability should be adequate to cover possible losses in stability that may arise from flooding, partially filled tanks, and the upward thrust of the ground or from the keelblocks when the vessel touches the bottom on being dry-docked. The case of longitudinal stability, or trim, is illustrated in Figure3.There is a direct analogy with the case of transverse stability. When a weight originally on board at position A is moved a distance d, to position B, the new waterline W1L1 intersects the original waterline WL at center of flotation (the centre of gravity of the water plane area WL),the new centre of buoyancy is B, and the new centre of gravity is G. For a small angle of trim, signified by the Greek letter theta(θ), θ=(a+f)/L wd=△GMl(a+f)/L Fig. 3 Longitudinal section of float ship showing change in stern trim as deck load w was shifted from position A to position B (see text ) Thus if （a+f）=1 inch =1/12 foot, wd =△GM/12L and this presents the moment to change trim one inch. The inclining experiment A simple test called the inkling experiment provides a direct method of determining GM, the metacentric height, in any particular condition of loading, from which the designer can deduce Changes in stern trim is x-y