No. of Or dinates. Longitudinal Metacentre of H. M. S. "Warrior," at 26'0 Displacement of the Ship, 301870 cubic feet=8625 tons. Distance between Ordinates, 18.3 feet. FORE BODY. 475 2 For both sides of ship. 955134.95 Deduct 17366.09 × (7.42)2 301870)145873199.425( 483.2 Long. Metacent. above Centre of Buoyancy. above ditto. 8.2 Centre of Gravity 475.0 Long. Metacent. above NOTE. [From Transactions of the Institute of Naval Architects. Vol. 5. 1864. By F. K. Barnes, Esq., Asst. Naval Constructor H.B.M.N.] CHAPTER XVIII. Geometrical Construction of Sails-Method of Determining the Position of the Centre of Effort of the Sails of a Ship-Calculations for the Position of the Centre of Effort of the Sails of the U. S. Steamer Brooklyn-Manœuvring by Sail. GEOMETRICAL CONSTRUCTION OF SAILS. The following rules may sometimes be useful: I. Square Sail (Fig. 19).—Given, the foot, BB, the depth, AC, and the area of a square sail : to construct its figure. Divide the area by half the breadth at foot; lay off the quotient, AD, upwards from the foot on the upright centre-line. Join CB, CB; and parallel to those lines, draw DE, DE. Through C draw a straight line parallel to BB, cutting the two oblique lines from D in E, E; join EB, EB; then EE will be the head of the sail, and EB, EB, its leeches. II. Triangular Sail (Fig. 20).-Given the foot, AB, the direc tion of one leech, AC, and the area of a triangular sail : to construct its figure. Divide the area by half the foot, and set up the quotient as a perpendicular, AD, to AB. Through D draw DE parallel to AB, cutting AC in E; join EB: ABE will be the required figure. III. Quadrangular Fore-and-Aft Sail (Fig 21).—Given the foot, AB, the weather-leech, AC, the direction, CH, of the head, and the area of a quadrangular sail to construct its figure. Divide the area by half the foot, and set up the quotient as a perpendicular, AD, to AB. Through D draw DE, cutting AC produced in E. Join CB; and parallel to it, through E, draw EK, cutting CH in K. Join KB. Then ABKC will be the required figure. Having made the principal calculations on the immersed portion of a ship or her displacement, the quantity of sail and its distribution, or the moving force required with relation`to the form of the vessel, is the next subject that demands the attention of the naval architect. A plan of the sails having been delineated by the draughtsman, the areas, centres of gravity, and centre of effort, or the centre of pressure of them, are found in the following manner : AREAS. I. Square Sails.-Multiply the depth by the half-sum of the breadths at the head and foot. II. Triangular Fore-and-Aft Sails.-Multiply any side by half its perpendicular distance from the opposite corner. III. Four-sided Fore-and-Aft Sails.-Multiply either diagonal by the half-sum of its perpendicular distance from the opposite corners. The centre of each sail is then to be found by one or other of the following rules : |