Today, I got away around 2:00, and worked till 7.
I took out the old bulkhead under the companionway, with a 4.5 inch metal cut off wheel on a grinder by laying it flat against the hull and grinding until I saw wood dust on both sides. Then I slid a long wood cutting sawzall under the bulkhead bending it into a j shape so it didn't dig into the hull and ran it from the bilge to the deck, and the bulkhead fell out. I ground out the old tabbing with a hitachi 7 inch grinder, and a norton 24 grit grinding disc or two. It is about the fastest way I have found to remove old tabbing...
On a fiberglass boat, it is worthwhile to remove the old tabbing as it is a secondary bond to the polyester fiberglass on the boat. Fiberglassing the new tabbing that holds the bulkhead in with epoxy, on top of a polyester tab doesn't make a whole lot of sense... while it will grab the wood, foam or coosa board better than the polyester resin would... it can also grab the hull better than the old tabbing can. So... I made a lot of dust.
After that I screwed a piece of luan to the old lip of the cockpit I left to stiffen the bridge deck while working... and used a tick stick to transfer the shape of the hull to the luan.
A tick stick is a piece of thin stuff, 1/4 inch or so by 1 1/2 wood with a few shapes cut in it. A lot of people use a tick stick with a few notches, number 1 2 3 or a b c along the notches so that it can show a long mark with a 3 and a short one with a 1.
I take my tick stick and cut a few hills and valleys, squares and rounds in it so that it can only be marked one way, and anywhere on its length is unique enough to be idiot proof. With a few V notches and a 1, 2, 3... I turn into an idiot...
With that done, I laid the luan down on a piece of junk 1/2 inch plywood, and laid my tick stick on each of the lines, marking the sharp end point with a pencil. Once the marks were there, I took a thin steel rule and used it as a batten (Traditionally a thin piece of wood with a clear straight grain and no knots so it bends uniformly...) I connected the dots, and cut it out.
Then I fit it to the bulkhead plywood to the starboard side, plumb to the world, and perpendicular the centerline of the boat. With that done I laid the starboard bulkhead on the port side, and noted the changes that needed to be made, by laying a scrap square of 3/4 inch plywood about 1 inch by 1 inch and marking the spots where it sees air.
Then I took the two bulkheads, and set them side by side in the boat, and scribed the overlap. (I purposefully left one just short of centerline, and the other real long...) and cut the overlap off the long one. I then set them together, and screwed a backer block of another piece of 1/2 inch plywood over the seam.
With that done, I took the full width plywood template out of place and laid it on top of a piece of 3/4 coosa board. Coosa board is a fiberglass filled polyurethane foam board that serves as a rot proof plywood replacement. I cut out the coosa with a jig saw, and then laid it on a piece of plastic.... on top of a piece of 3/4 plywood... on top of my table saw. (The only surface I have at the moment that is flat...)
I then cut out a piece of 1708 fiberglass, and laid it over the coosa and marked it out with a sharpie and cut it, then fiberglassed it with west systems epoxy using 60 ounces...
Tomorrow I will fit the bulkhead, relevel the boat (as it is on a sand lot and shifts with a lot of rain...) and glass it in place.