Completing the bottom

After the epoxy set on the first side of the bottom at the stem, it had to be trimmed at the stem so the final piece could overlap it.  Before gluing it in I used the first trimmed piece as a template to cut the second piece. This made it pretty close to the correct fit and eliminated a lot of the guesswork of trimming the piece.
Starting at the butt joint and keel, I started screwing the piece down with temporary screws.  I wrapped the plywood around the chine to the stem by putting a screw every 6" along the chine.   I was able to pull the plywood tight without soaking it or resorting to a jury-rigged clamping scheme.
With the plywood in position, I had to cut two transition joints.  One is along the keel at the stem.  The plywood butts to the adjacent piece until it starts bending down the stem, then it needs to overlap.  The other transition joint is along the chine.  The multifunction tool described in the previous post was invaluable in cutting these joints. It is possible to cut the plywood in place so you can keep trimming until it fits.  This eliminates having to remove, trim and refit over and over.
The result is a great fit without a lot of work. It amazes me how a pieces of flat plywood can be bent into a curved boat hull.

Here is the finished hull with the last bottom piece epoxied in place and also trimmed to its final shape. I used some epoxy and wood flour (fine saw dust) to make a filler that I used to fill the gaps between the butt joint along the keel and also along the chine.
When attaching the sides and bottom, I used a lot of cheap plated screws from Home Depot. These are much stronger than the silicon bronze screws so it made attaching the panels easier.  You didn't have to worry about a perfect pilot hole or breaking them off.   Now, with the epoxy holding the panels in place, I replaced all the steel screws with the silicon bronze screws.  I had to drill a proper pilot hole through the plywood so the shank of the SB screw would not bind and cause a breakage.   I thought I would have to countersink each hole, but that was not required.  I could draw the screw down and it would compress the plywood and sink itself below the surface. This is needed so the screw holes can be filled and sanded smooth.
The bottom will be painted but I want the sides finished "bright".  This means the mahogany plywood will be finished naturally so the wood grain shows through. This requires that the sides are clean and any screw holes filled to match the mahogany.  More on that in a later post.
I also wanted the transom to be finished bright so I covered the transom with a piece of 3/8" plywood which I glued and screwed to the existing transom.  The screw holes will be filled to match.

Here's the transom attached and waiting for the epoxy to set. The screws with wooden washers are drywall screws that I used to hold it in place for gluing.  I then added additional clamping by using the final silicon bronze screws over the rest of the panel.  I'll only have to replace a few when it dries.
I should note that I was thinking ahead before I did this.  The transom was screwed to the building form (you can see part of it in this picture.)  I removed those screws before I skinned the transom with this mahogany plywood.  If not, I would have had a mess trying to remove the boat from the form as I would have had to cut it off from the inside. 
Next up is filling the holes and prepping the hull for encapsulating in epoxy, which is the last step before fiber-glassing the hull.