: . . . I was looking to cut corners
: with the plywood and save a little time. Boat wants to get wet.

You can do plywood bulkheads now and later cover them with short strips. The added weight would be negligible maybe around 4 -6 ounces. Or, you can just glue up a panel of short strips. Once you have a pattern for your bulkhead, draw it on your plywood, lay a sheet of freezer wrap or wax paper on top so your strips won't stick, and then lay down strips that are a bit longer than needed to cover the outline of your pattern. If you are using real short pieces you cna butt them against one another to gt the needed length, just like you did to strip your boat. When the glue dries you won't have much waste to cut away to get the right shape. A quick scrape to get off the glue drips, and a fast sanding job (both sides are flat an the bulkhead will fit on a table top) and you are ready to attach it. Shouldn't take more than three hours longer than working with plywood, and most of that time is waiting for the glue to set up. If you make both bulkheads at the same time, you only have to wait for the glue to set up once.

: Where does the most stress occur to the
: bulkhead due to expansion? I have sheer clamps in this stripper and was
: thinking I could tack the bulkhead to them to position it, and then leave
: a slight gap everywhere else to be covered by glass and allow for a little
: movement. Would seem to be sufficient strength at the sheer so that any
: movement wouldn't poke through. Or is it the bulkhead that would suffer?

There are a few engineers on this board who can give you more technical and precise information on this. As I see it, though, you have a few situations where the bulkhead would have some involvement in the structure of the boat.

First, think about sitting on the boat. You might do this during an entry. when you put your weight on the boat, if there is no brace, like a thwart in a canoe, to kep the boat from spreading wider, then the weight on the deck would cause the boat to spread wider. Enough weight and the boat gets wider and is not so high. An extreme change in shape can affect hull strength, and the flexing involved is putting its own stress on the structure. Imagine a whitewater boat caught on rocks, with half of the length exposed to the rapid flow of water. The pressure and weight involved could fold a boat in half.

Now imagine the same situation with a bulkhead. Weight on the deck can not collapse it easily for two reasons. First, the bulkhead would have to compress, top to bottom under the weight, and second, the glass across the width of the bulkhead acts like the bowstring on a bow, or a thwart on a canoe, and keeps the width from spreading. Nowimagine the whitewater situation. With a significant amount of the boat being exposed to rushing water, the hull would try to flex in a smooth curve. (think of a bow being pulled back by an archer). the side getting the most pressure from the rushing water would try to stretch, while the other side of the boat (the lee side) would try to compress. In doing so, the deck and hull would get closer, losing structural strength, until the whole boat folded in half. with a bulkhead in there, though, the pressure from the water side would get transmitted to the lee side by the bulkhead. That would focus the forces on the area where the bulkhead contacts the hull.

Now, the $64 questions are: Exactly how much force does it take to destroy the boat with a bulkhead, and how much force does it take to destroy one that does NOT have a bulkhead. and finally, does a bulkhead mounted "loosely", so as to permit a little play, have any influence on these numbers. For these answers I refer you to the number crunchers.

As for mounting your bulkhead: since you have a sheer chine, may I suggest you use a 1/16th inch drill bit and drill a tiny hole in each sheer strip where you want the bulkhead mounted. 1/2 inch deep is fine. Fill each hole with a drop of glue and a 1 inch piece of toothpick -- which should stick out about 1/2 inch. The toothpicks will be srong enough to support the bulkhead, small enough to glass right over, and jsut the right color to blend in with your wood. If you need a spot on the keel for a third bulkhead support, put in a small block of wood with duck tape, or a small drop of hotmelt glue. You can remove this after the first side is glassed.

hope this helps

PGJ