45° 15° Calculation of GZ Levers for Stability Cross Curves, Using the Integrator and Tchibyscheff's Rule. M 4511 5,290 5097 +.586 +.586 3.560 5097 8,700 4931-.166 +.420 1.550 5169 7.224 12,280 4974.195 +225 .590 5211 3 5519 2107 5519 2 7874 2355 7874 8,680 0820 +.271 +.958 3,550 1056 7.210 12,250 1411 +355 +1.313 2.950 9.565 16,300 1999 +352 +1.665 3.260 2235 L.W.L. 0365 2491 12.056 20,400 2463 +228 +1.893 2.970 1647 0365 2699 1.896 Check 90° 75° 60° Calculation of GZ Levers for Stability Cross Curves, Using the Integrator and Tchibyscheff's Rule. 9,520 6051 +.504 +1.182 4.00 6285 7.649 13,000 6637 +.352 +1.534 3.80 6871 5976 2230 9.879 16,800 7186 +.315 +1.849 3.50 5976 7420 CHAPTER II. DESIGN. In the foregoing pages we have treated with the various calculations which confront the naval architect, but the relation of these to one another and to the particular qualities that the projected ship shall possess belong to Design. In designing the ship, nothing should be left to chance, or what is the same thing trial and error. The vessel must first be designed with figures. Before a single line is run on paper, the various element coefficients should be carefully selected and their functions worked out in consonance with the results desiderated in the finished ship. The relation of these coefficients to one another must be firstly mastered for all types of vessels and conditions of draught and trade, when with the aid of the tables given an unerring selection will be possible and a definite result attained. When the way is prepared for the drawing part of the design to be taken in hand, it will be found advantageous to have a definite routine in which to prepare the various views comprised under the general term "Lines." Each step should be taken in its proper time and order. Much time will thus be gained, and a clearer conception of the art of designing obtained. To this end we submit the following method as one fulfilling these propositions, dividing the task broadly into two parts, viz. : (a) Figures and (b) Lines, the first embracing the moulded dimensions, draught, element coefficients, and their functions, and the latter, the sheer draught, half-breadth, and body plans. The shipowner will specify the trade for which the ship is intended and the limit of draught on the particular service proposed. It will generally be found economical to take advantage of the maximum draught permissible. When the dimensions are solved to meet the requirements stipulated, the grade numerals should be worked out, for the Classification Society's Rules in which it is proposed to class the ship, and if it be found that a grade can be saved either in plating, framing or equipment numerals, or the requirements for extreme proportions evaded by a slight alteration or adjustment of the dimensions, this of course should be done. As an example we shall postulate that the shipowner requires a 3-deck freighter with complete shelter deck to carry 10,000 tons dead weight, exclusive of coal for 12 days' steaming, fresh water and stores, on a mean draught of 27 feet with a B.T. Freeboard and a sea speed of 12 knots. The ship to be classed in American Record and to conform to the U.S. Inspection Laws. To these |