on a minimum gross tonnage, (3)appropriate strength of construction, ( 4) the most efficient type of propelling machinery with due consideration to weight initial cast, and cost of operation, (5) stability and general seaworthiness, and(6) the best loading and unloading facilities and ample accommodations for stowage Design procedure From the specified requirements, an approach is made to the selection of the dimensions, weight, and displacement of the new design. This is a detailed operation, but some rather direct approximations can be made to start the design process. This is usually done by analyzing data available from an existing ship which is closely similar. For example, the design displacement can be approximated from the similar ship's known deadweight of, say, 11790 tons and the known design displacement of 17600 tons. From these figures, a deadweight-displacement ratio of 0.67 is obtained. Thus, if the deadweight for the new design is, for example, 10000 tons, then the approximate design displacement will 10,000/0.67 or 15000 tons. This provides a starting point for the first set of length, beam, and draft dimensions, after due consideration to other requirements such as speed, stability, and strength. Beam is defined as the extreme breath of a ship at its widest part, while draft is the depth of the lowest part of the ship below the waterlin Length and speed These factors are related to the hull form, the propulsion machinery, and the propeller design. The hull form is the direct concern of the naval architect, which the propulsion machinery and propeller design are ??? concern. The naval architect has considerable influence on the final cisions regarding the efficiency, weight, and size of the propeller, as both greatly influence the gn of the hull form Speed has an important influence on the length selected for the ship. The speed of the ship is related to the length in term of the ratio V/VL, where v is the speed in knots and L is the effective waterline length of the ship. As the speed-length ratio increases, the resistance of the ship increases. Therefore, in order to obtain an efficient hull form from a resistance standpoint, a suitable length must be selected for minimum resistance. Length in relation to the cross-sectional area of the underwater form(the prismatic coefficient), is also very important insofar as resistance is concerned. Fast ships require fine(slender) forms or relatively low fullness coefficients as compared with relatively slow ships which may be designed with fuller hull forms Beam and stability A ship must be stable under all normal conditions of loading and performance at sea. This means that when the ship is inclined from the vertical by some external force it must return to the vertical when the external force is removed Stability may be considered in the transverse or in the longitudinal direction. In surface ship, longitudinal stability is much less concern than transverse stability. Submarines, however, are concerned with longitudinal stability in the submerged condition The transverse stability of a surface ship must be considered in two ways, first at all small angles of inclination, called initial stability, and second at large angles of inclination. Initial stability depends upon two factors, (1) the height of the center gravity of the ship above the base ne and (2)the underwater form of the ship. The center of gravity is the point at which the total weight of the ship may be considered to be concentrated. The hull form factor governing stability depends on the beam B, draft T, and the proportions of the underwater and waterline shape. For aon a minimum gross tonnage,(3) appropriate strength of construction,(4) the most efficient type of propelling machinery with due consideration to weight, initial cast, and cost of operation, (5) stability and general seaworthiness, and (6) the best loading and unloading facilities and ample accommodations for stowage. Design procedure From the specified requirements, an approach is made to the selection of the dimensions, weight, and displacement of the new design. This is a detailed operation, but some rather direct approximations can be made to start the design process. This is usually done by analyzing data available from an existing ship which is closely similar. For example, the design displacement can be approximated from the similar ship’s known deadweight of, say, 11790 tons and the known design displacement of 17600 tons. From these figures, a deadweight-displacement ratio of 0.67 is obtained. Thus, if the deadweight for the new design is, for example, 10000 tons, then the approximate design displacement will 10,000/0.67 or 15000 tons. This provides a starting point for the first set of length, beam, and draft dimensions, after due consideration to other requirements such as speed, stability, and strength. Beam is defined as the extreme breath of a ship at its widest part, while draft is the depth of the lowest part of the ship below the waterline. Length and speed These factors are related to the hull form, the propulsion machinery, and the propeller design. The hull form is the direct concern of the naval architect, which the propulsion machinery and propeller design are ???? concern. The naval architect has considerable influence on the final decisions regarding the efficiency, weight, and size of the propeller, as both greatly influence the design of the hull form. Speed has an important influence on the length selected for the ship. The speed of the ship is related to the length in term of the ratio V/ L , where V is the speed in knots and L is the effective waterline length of the ship. As the speed-length ratio increases, the resistance of the ship increases. Therefore, in order to obtain an efficient hull form from a resistance standpoint, a suitable length must be selected for minimum resistance. Length in relation to the cross-sectional area of the underwater form (the prismatic coefficient), is also very important insofar as resistance is concerned. Fast ships require fine (slender) forms or relatively low fullness coefficients as compared with relatively slow ships which may be designed with fuller hull forms. Beam and stability A ship must be stable under all normal conditions of loading and performance at sea. This means that when the ship is inclined from the vertical by some external force, it must return to the vertical when the external force is removed. Stability may be considered in the transverse or in the longitudinal direction. In surface ship, longitudinal stability is much less concern than transverse stability. Submarines, however, are concerned with longitudinal stability in the submerged condition. The transverse stability of a surface ship must be considered in two ways, first at all small angles of inclination, called initial stability, and second at large angles of inclination. Initial stability depends upon two factors, (1) the height of the center gravity of the ship above the base line and (2) the underwater form of the ship . The center of gravity is the point at which the total weight of the ship may be considered to be concentrated. The hull form factor governing stability depends on the beam B, draft T, and the proportions of the underwater and waterline shape. For a