APRON TO SIDE/BOTTOM/TRANSOM FRAME PIECE

[bob mitchell]

     This is a tough piece (for me anyway) that is bowed and curved, and beveled, as well as notched out. It starts at the bottom/side/transom junction (back corner), where it also recieves the chine, and butts at the other end into the apron.  It is what holds the bottom to the transom, with the bottom overlapping this piece and the transom layers. Here is a shot of the stb. old and my first attempt at the new. The slanted area under the first layer is what recieves the chine. You can notice the bow as well as the curve. The bevel on the sides is about 55 degrees, so expect to do some hand work if your bandsaw only goes to 45. You can't get away with the usual minipulative tricks to get the extra 10 degrees because it is curved.

        In the next photo you can see that I did not get enough bow. (see the space between the bottom and the piece.

What the bow does, combined with the bevel and the curve, is give the correct contour for the bottom. Here is my next attempt in which I add significantly more bow during epoxy time. Won't get to try it until tomorrow. My order of operations are bandsaw the shape and bevel, then try to create the bow

In the old piece in the background there is a small try square intersecting the slanted area exactly the way the chine would intersect.  This piece was originally built as part of the transom. I have not decided yet if I am going to attach it to the transom before installation, or attach it to the apron as a guide to transom installation.

     A few  things I noted were: 1) over the approximate 3' length of two 3/4" plywood pieces a bend of 1 1/2" is significant, in the sense that if you take the clamps to soon you loose your bow. In fact I ended up putting a few stainless steel screws in at a steep angle to resist the debowing. 2) If you don't have a "form" to bend over it is beter to use a 2x6 or 2x8 so the bend forces are distributed to create a better arc. If you use a narrow piece all the stresses are concentrated and you get just an angle instead of an arch. and 3) for you esoteric bandsaw affisciendo's (?),

depending on how you trace the old piece, the upside of the angled bandsaw bed is cut 3/4" behind the outline, and the downside is cut on the line - thought I might save you a piece of wood if I got you to think about it, unlike some

neophytes I know! 

EPILOG 1:

well, speaking of esoteric, I woke up this morning, started thinking about "the piece" , now that I have tactally (?) fed myself data for two days, and it is beginning to reach my brain............. the curve and the bow work together to give an essentially flat surface along the surface that the bottom joins to. Said another way, we know the transom curves, and if we felt like using a piece of solid wood, we could cut the transom curve profile, and then plane a flat surface for the bottom underneath (or just use a flat side of the board) ....as well as the plane for the transom / bottom intersection angle along the curve.   In a nut shell, as in the jig alternative with plywood, to get the plywood to bow to match the transom, it had to be cut on a curve so that when it bowed the "bottom's" surface would stay essentially straight!

A perfect analogous example would be spiling a board!   Put that in your pipe and smoke it!!!!! May play with the theory a little today.