Page 59: How To Read And Use Ship-Model Drawings
All one has to do is trace the water lines on the half-breadth plan on heavy wrapping paper and cut out the templates for making the lifts, as described in the article on the “Half Moon” previously mentioned. Care must be taken to make the wood used for the lifts the same thickness as the distance between the water lines. If working from a small drawing, as in a magazine or book, the lines of the hull can usually be enlarged without much trouble also. For example, the drawings of the “Santa Maria,” given here, show a hull 43/8 in. over all. If this is enlarged twice, it would be suitable for a small space; enlarged three times it would be 13 1/8 in. long, which is a very nice size for a larger model. The procedure of enlarging is simple. Draw a center line on a sheet of paper, measure the distance from station to station with a pair of dividers, then, starting at station 1, step off this distance twice with the dividers and make this point station 2. Do the same all along the line for the other stations. At these points erect perpendiculars to the center lines, then take off, on the original half-breadth plan, the distance from the center line to the point where the first water line crosses station line No.1. Step this off twice on the new plan, then do the same with stations 2,3 and so on. This will give a series of marks through which the new water line can be drawn. The same method is used for making all the drawings, taking the measurement on the original with the dividers and stepping it off twice on the new plan. If the design is to be enlarged three times, step all the dimensions off accordingly.
Occasionally the distance between the water lines on the blueprints is an odd fraction, like 7/16 in., and no lumber this thickness can be obtained for the lifts, or the modeler may want to use wood of a different thickness which he has on hand. Suppose we have wood 1/2 in. thick we want to use, and that the distance between the water lines on the drawing is some other measurement. To make new water lines for the lift templates is easy. Take the body plan, and, starting at the top water line, draw new lines on the print 1/2 in. apart, taking care to keep them at right angles to the vertical center line. (See Fig. 4.) Now draw a center line on the piece of paper to be used as a template, and draw the station lines at right angles to this. Number them on the blueprint. To make a new water line A, take off with the dividers the distance from the center line to the point where the cross-section line of the stern, marked S, crosses line A, and transfer this measurement to the template. Then, still on line A, take off the measurement of the cross section 1 and transfer this to the template at station 1. This is shown in Fig. 4. Still keeping on line A, transfer all the cross-section points to the corresponding station marks on the template, then draw, through the marks, the new water line. This need only be done on one side of the center line on the template, as, if the template is folded along the center line as indicated, both sides will be alike.
Where the scale of the original is unsuitable, and the model is to be made to a different scale, it is well to have a set of paper scales, which can be obtained from drafting-supply houses. In the absence of these, the model builder can make his own. Suppose the original scale is 1/4 in. to the foot, and the model is to be made to 3/4-in. scale. Make two scales from pieces of bristol board, about 12 in. long and 3/4 in. wide. Graduate one of them every 1/4 in. and the other every 3/4 in., as shown in Fig. 5. Make the first graduation from the left-hand end of the scale zero, and the remainder 1,2,3, etc. Every graduation will then represent 1 ft.
