Carl H. Clark

Great care must be taken that the frames do not change their shape after being bent into place. There is always a tendency for the frames to straighten out after a time, and this must be guarded against. The bilges are the points where this change is first noticed, as there will be a tendency for the bilge to become more round than when they are bent. This would give the boat less displacement than designed and be less satisfactory. It can be guarded against by laying short pieces in the bilge across the three frames between each two moulds and running a brace from them to the beams overhead. This will keep the bilges down into place and make the structure stronger during planking.

A floor, as shown in the cross section, is bent in on the top of each frame; this floor is a piece of the same section as the frame and about 24 in. long with the outer corners rounded off. It is steamed and bent down the throat of the frame and held there by a large nail driven through. These nails should be galvanized, 3 in. long and of the wive type, as they do not cut such a large hole in the floor as the cut type. It will be found necessary to bore for these rather smaller than the nail and yet have a good driving fit. In the forward end of the boat the angle of the frames will be so acute that the floors cannot be bent in, and either a natural growth knee must be used or a piece of | in. board cut to shape and fitted alongside of the frame and fastened through. At the stern, floors must be worked over the horn timbers, bent to shape or of a piece of board notched over the horn timbers and fastened alongside of the frames. These floors are a very important item in the construction, as they tie the two sides of the boat together and add greatly to its strength, although they are a matter which is often neglected by builders of small launches The rabbet in the keel is to be trimmed out so that a 3/4 in. plank will lie on the frame and bed firmly into the rabbet. The angle will, of course, change at all points, and can be obtained by laying a piece of £ in. board with square edges onto each frame and trimming out the rabbet until it fits squarely into it. The rabbet in the stern is trimmed to suit the squared end of a long piece which is bent around the frames about as the planks would run. The sternboard also must be bevelled off to the correct angles, as shown by the ribband bent around the frames and across the stern-board.

In planking, the top streak should be the first to be put on, as it will stiffen the boat, and is also the easiest. The height of the sheer, as marked on the moulds, is that of the deck or top side of the covering board, and since the covering board fits on the top of the top streak, we must fit the latter 3/4 in. below the marks already made in the moulds. A ribband should be clamped around the tops of the frames § in. below the marks already made and the sheer line marked on each frame, not only on the face, but on the sides. The plank may be either hard or soft pine, or cedar; the first is rather harder to work, but comes in long lengths and is a very strong wood, making a very smooth boat, while the two last are easy to work and fit, but come in short lengths, requiring many butts, but are, on the whole, more economical of stock. It is advised in any case, that the top streak be of oak, as it may be finished bright and is very ornamental. If possible there should be no butts in the top streak. The boards from which the planks are to be fashioned, must be much wider than the plank which they join. On account of the curvature of the plank, this width will sometimes need to be nearly double that of the plank so that the boards for this purpose ought to be 12 in. or so in width. To lay out the top streak, the boat is laid on the frames, bent around and clamped into place, the marks made on the sides of the frames are transferred to the plank, thus giving the curvature, the mould points are marked across the plank to enable it to be replaced in the same position, fore and aft. The plank is then removed and a line drawn through the points with a pattern. There will be a considerable amount of curvature to this plank so that it cannot be gotten very wide out of a single board; this width should, however, be made as great as possible, up to 7 or 8 in. The lower edge of the plank is also laid out, it being tapered somewhat toward the bow and rather narrow at the stern.

The plank is now sawed out and the edges planed carefully. It is then clamped on to the frames again and fitted to the marks, and necessary fitting done. Care is to be taken that it is replaced in exactly the same fore and aft position as when the marks were made. The forward end may be cut off to fit the rabbet; the angle can be obtained by laying a rule or straight edge across the plank and sighting it even with the edge of the rabbet. It should be cut off with a fine tooth saw, leaving a smooth end. The after end is left long for the present. In fastening the plank on, the forward end should first be clamped to the stern and pressed firmly into place then bent around and clamped wherever possible. All fastenings must be bored for and should be set below the surface of the plank 1/4 in. by boring with a larger bit, the hole thus left being plugged later. At the stem and stern the fastenings are brass screws about 1 1/8 or 1 3/4 in. long. The frame fastenings may be either copper rivets or galvanized iron nails. Brass screws are sometimes used, but the writer does not recommend them, on account of their brittleness. Galvanized iron nails are cheap and strong, but should not be too large wire, and should be clinched on the inside; this makes a very good piece of work. Copper rivets are, however, the most satisfactory fastening, although they cost somewhat more and are rather more work to put in. A boat fastened with copper is, however, more valuable, and this fastening is recommended with a washer on the inside. Nails for this purpose should be long enough so that there is about 1/2 in. to cut off before riveting, as in this way the strongest part of the nail is used, the point being so slim as to have but little strength. In fitting, the washer or burr is driven on to the rivet with a rivet set. This is a piece of steel with a hole in it rather larger than the rivet; and by using this and holding a heavy pointed piece of iron against the head, the burr, which should be a close fit for the nail, may be driven on tightly, drawing the plank and frame together. The end is then cut off, leaving about 1/4 in to head over, which is done with a riveting hammer, the weight being held against the head as before. This makes a very firm fastening, when well done, but the hole for the nail must be a driving fit with no play, or the nail will cripple or bend when riveted and a poor fastening will result. The top streak should be fastened thus along the lower edge into every frame and at intervals along the top edge; the latter is not very important at present. The second streak may also be put on, as it is desirable that some experience should be obtained before going to work on the more difficult planks on the bottom. On this plank it may also be possible to obtain the curvature by bending the board around and marking it, but practice should be obtained in taking the "spiling " or curvature by measurement. The space around each mould between the lower edge of the top streak and the keel should be divided up into the same number of equal parts of about the width which the planks will be. This is for use as a guide in making the several planks taper regularly towards the ends.

The method of laying out the plank is shown in the illustration; the batten is about 4 in. wide, so as tobend without springing sidewise, and about Jin. thick. It is laid on around the frames near the edge to which the next plank is to be fitted, and clamped in place. Measurements are then taken from the edge of the planks and recorded in chalk on the bottom, together with a mark showing just where the measurement was taken; as shown in the figure, sketch A. It will be seen that this bottom simply locates a base line from which measurements may be taken. The bottom is then laid on the board from which the plank Is to be cut, as in sketch R, and the measurements laid off onto the board. A line drawn through these points with a narrow batten is a very close approach to the true shape. The wide batten may now be removed and the lower edge of the plank drawn in, tapering the plank towards the ends, as before directed; the divisions already marked on the moulds will aid in making the taper equal on all the planks. When the plank is shaped it will look like sketch C, the mould points being marked in it to facilitate replacing it in the proper position. It is then cut out and smoothed up with a plane. The plank is then bent around in place and any discrepancies noted; the forward end is cut to fit the rabbet. It is taken down, the necessary fitting is done, and the planks may now be used as a pattern for the corresponding plank on the other side of the boat, which is fitted into place in the same manner.