Fig. 451.
A small boat can be made as shown in Fig. 451. The dimensions can easily be altered. The particular rig given is merely for illustration, for this is not a book on sailing, and you can find all the facts you need about rigging in any good book on the subject. If you are a novice you had best be content with a simple leg-of-mutton sail (Fig. 448), which is, for the beginner, the safest and most easily managed. A spritsail (Fig. 449) or some other simple form can be used if desired. If you know how to sail a boat, you can adopt such rig as you think best.
Fig. 452.
First get out the backbone. Get a piece of clear spruce, or pine, perhaps 12' × 3" × 4". A round spar may be used. Be careful to select good lumber, as great strain is put upon it. A piece which has naturally sprung lengthways should be placed with the convex edge upwards. Next get out the runner-board, perhaps 6½' × 2" × 9", of spruce. Pine is also good, or any strong wood will do. Choose a clear, sound plank. If naturally sprung in a bow-like curve, put the convex side upwards. Smooth the pieces sufficiently to avoid splinters and roughness. Thin the runner-plank on top each way from the centre down to about an inch in thickness at each end, if you can have it sawed at the mill. It is hardly worth while to do this by hand. Fasten the runner-board, at exactly the middle of its length, across the backbone, at a point perhaps 6½' from the stern end, with a strap-hanger (Fig. 452) screwed up with nuts and broad washers on the under side. If you cannot afford this, put a bolt through both pieces (see Boring), tightening underneath with nut and washer, and putting cleats on the runner-board (Fig. 453). Be sure that one edge of the runner-board is straight and at right angles to the backbone. Nail a piece of board, 18" long and 3" wide, across the stern end of the centre timber. Add the two side pieces a b and c d (Fig. 450), of 2" spruce joist, nailing them firmly in place, thus forming the sides of an irregular box (see Nailing). Turn the frame over and nail a bottom on this box, laying the boards crosswise and nailing to the backbone as well as to the sides and end.
Fig. 453.
Next, to make the runners, get out six pieces of oak, or other hard, strong wood, 9" × 3" × 4". Mark with the square from the straightened edge of the runner-board the positions for the inner blocks, equally distant from the backbone, screwing them in place (Fig. 454), with one screw in each. Measure across with a stick from one to the other at each end to see that they are just parallel, and also test their being at right angles to the runner-plank, which in turn must be at right angles to the backbone, in order that the runners may be parallel and not slewed sideways. Having tightly screwed these inner blocks, brace them with angle blocks, as shown. The outer blocks can next be fitted, leaving just space enough for the runners to play freely, but not loosely, between the blocks. The holes for the pins for the runners can be bored in the outer pieces before they are screwed on. Then, using these holes as a guide, those in the inner blocks can be bored in line. The runners themselves should be carefully made and fitted, for they are a very vital part of the boat. On the large boats they have usually been made of oak, with a shoe of cast iron at the bottom attached by bolts, but this is quite a piece of work for a small boat and you can get the blacksmith to work out the whole runner, with a hole bored for the pin-bolt. Make a pattern about 18" or 20" long, rocking very slightly in the middle and more quickly near the ends. The hole for the pin should be back of the middle, so that more of the shoe will be in front of than behind the pin. This is to lessen the shock when the runner strikes an obstruction. The cutting edge may have an angle of about 45° for trial (Fig. 455). If too blunt or too sharp you can alter it. It will take considerable filing to get the edge true, straight, and uniform (see Filing). Finish with an oil-stone.
Fig. 454.