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Ship floating upright : • The centers of gravity ( CG ) and Buoyancy ( B ) are on the center line. • The resultant force acting on the ship is zero . • The resultant moment about the center of gravity is zero . • Upright Hydrostatic Analysis Why to Use Upright Hydrostatic Analysis ? Used to determine hydrostatic equilibrium and stability for Ship . If the vessel is subject to classification, hydrostatic properties must be submitted as part of that procedure . Hydrostatic properties will be communicated to the owner/operator of the vessel to be utilized during loading and operation . In Case of Grounding & Collision , hydrostatic properties may be crucial in the conduct and success of salvage operations . • Hydrostatic Calculations : • The input to the hydrostatic calculation is in most cases a form of offsets on transverse stations. • Graphic views of the offsets are beneficial . Longitudinal View : Gives good indications of the quantity and quality of data. Transverse view: Good supplement to the longitudinal view. Curves of Form • For a vessel that operates at a significant range of loadings (displacements), the hydrostatic properties must be presented for a range of flotation conditions. • It is customary to use vessel draft as the independent variable, and to tabulate properties at a reasonable number of draft values . • This information is presented graphically at curve called curves of form : The Draft (T) is the vertical axis : Because draft is a vertical measurement. Dependent quantities are plotted horizontally. If plotted it will appear as follow: The plot is complicated by the fact that the various hydrostatic quantities have different units and widely varying magnitudes. Therefore, a generic “scale of units” from 0 to 10 is used, and quantities are scaled by powers of 10 (and sometimes other factors) to fit on the plot. The range of draft should go from somewhat below the minimum working displacement to somewhat above the deepest loading expected .