Page 58: How To Read And Use Ship-Model Drawings
These lines are of more importance to the designer than the model builder, but they do serve to a point a warning, and that is, that, no latter from what angle the hull is viewed, when completed, all the curves should be “fair,” as the designer calls them, that is they should have a smooth, clean sweep from one end to the other, with no humps or hollows in them.
When we take a loaf of bread and slice it, we produce exactly the effect of the lines in the body plan. The lines in this plan represent cross sections of the body as they would appear if the block were cut straight across at regular intervals along its length. Note the upper right-hand drawing in Fig. 2. These lines are very important for the modeler, since from them he cuts the templates that enable him to give his hull the correct shape. The cross sections are taken, as stated, at regular intervals along the hull; these are called the stations, and are numbered from 1 to 13 in Fig. 1. The stations are similarly marked on both sheer and half-breadth plans. The designer does another thing with the body plan that puzzles the beginner. In order to show all the cross sections on one plan without confusion, what he does, in effect, is the same as if he had split his hull in two down the center and then turned one half end for end. That is, the left-hand half of the body plan, in Fig.1, shows the cross sections of the ship as viewed from the stern, while the right-hand half shows the cross-section lines as viewed from the bow. This can be understood by comparing the number of the lines on the body plan with those on the sheer plan. Line No.1 on the body plan is a cross section of the hull at station 1 on the sheer plan, and line No. 13 on the body plan is a section at station 13 on the sheer plan.
There is one thing to bear in mind in connection with the last-mentioned line, No. 13, and that is, that the bow curves forward to the stem from this line. This may seem apparent, and it is easily seen from the sheer and half-breadth plans, but I have seen model makers very puzzled over this. Line 13 is shown at A in Fig. 3, and the model makers referred to were carving the hull as though the side were cut straight in at this point, as indicated at B. The proper shape, of course, is shown at C.
Where the blueprints or drawings are made to such a scale that they are the full size of the proposed model, their use is simple.
