Chine
Continued...
Bending and shoving the chine exerts considerable stress on the hull framework so be sure the structure is well braced and won't move. Bending in the chine for left and right sides simultaneously is desirable to equalize stress. Some, however, feel doing one at a time is preferable and the lesson learned on the first makes the opposite sides easier.
 The forward frame is beveled so that
the chine will have a flat landing. |
A few hints on bending the chine in place. Fit the junction with the stem first leaving overhang at the transom. It'll probably take several cuts to properly fit the chine to the stem. Use clamps to hold the frames in the frame notches in the aft section. C or bar clamps anchored to the forward portion of the chine will provide leverage and a handle to bend and twist the chine against the stem while fitting. The actual position of the chine on the stem is not critical. Twisting the chine will alter its ending on the stem. Move the chine at the stem up or down so it forms to the frames and mates flat against the stem contour. This can be visually illustrated by using a 1/4" plywood strip the width of the chine extending aft of the stem a frame or so to represent what the actual chine must accomplish. The thin plywood will exaggerate what will take place when the solid member used is bent in place. Sometimes the chine will simply not mate to the forward frame so it parallels the side. A small amount can be faired off but realize an excessive amount may destroy the member's integrity. The following assumes the boat is being built upside-down. If the top edge of the chine does not mate solidly against the forward frames, try twisting the chine and letting it land on the stem closer to the sheer edge. If the chine lower edge projects, try moving the chine/stem junction the reverse direction. If you have the chine in place and one of the above conditions still exists, all is not lost. Shims on the inner or outer surface can be used to add material to the chine so it can be faired properly. Finish an outer shim in a long taper so the transition from chine to shim is a smooth fair plane.
The chine sides to the stem in a long compound taper as it junctions against the stem side; typical construction for this type of craft. However, a continuous flat area for the side and bottom planking, stem, and chine must result after fairing. Easier said than understood by most. The stem is usually partially beveled, but final trimming done after the chine is permanently installed. If the chine protrudes too far, it can be faired to a certain extent; if set in too far, a shim will be required.
The photo above illustrates a plywood fixture we have found helpful to determine the position of the chine on the stem side. Keep in mind what has been stated in the foregoing. The bottom and side must mate to the stem and chine on a continuous surface. The chine can't be located on the stem so that the stem/chine junction cannot be faired to a flat plane. Take small pieces of plywood and simulate the side and bottom joining on the stem to help visualize what the finished junction will look like.