Sunday, April 1, 2012

Optimist Pram - taking real shape

For quite some time we've just imagined the Optimist sitting on the strongback, but now the outline of the dinghies has been reveled. Ric Altfather, president of the Cleveland Amateur Boatbuilders and Boating Society, offered us some good advice when assembling our Optimists. The bend we had to make to instal the chine is a bit too severe for most 3/4 x 1 1/2 inch kiln dried lumber. Ric recommended we soak them prior to trying to bend them in place. We let them float on the pool cover for a few hours - this seemed to work well. They would have snapped like a twig if they had not been soaked.

We are now contemplating the next step. We need to fare all the edges with a hand plane and sander to prepare for the eventual plywood skin that will make these real boats.

Part 4:

The three frames looking really nice in the garage.

To take the twist out of the chine at the center bulkhead we clamped a board to the stringer and then screwed the bottom of the board to the frame leg. We let the wood dry and take the shape for a couple days before putting the screws through the chine. I'm not sure it is necessary to wait that long, but we had the time to let it dry and didn't rush it.

To mark the spot in the bow to let-in the chine, we used the paper pattern that was supplied with the CABBS' plans. With the chine stringer well soaked I was able to spring it into position to check my pencil line. I made some slight changes to the template line to adjust for a better fit after cutting the notch.

I found that it was pretty easy to put a pilot hole in the frame leg to make the final cut for the gunwale stringer. I drilled the hole to match the angle that the stringer would be let-in. I cut from the front and then moved to the back to check that the line was being followed on both sides. I would cut a little bit and then check about three or four times to be sure I wasn't straying from the lines on both sides.

Here I am checking to see if the bow is perfectly parallel to the center frame by laying a board on the bow and sighting across. There was a very slight twist that I was able to remove by weighing down the corner of the strongback with some stones (see bottom left) and shimming one of the back legs.

1 comment:

  1. I am at about this stage in my constriction but have a problem tryo,ng to apply the side panel. I cut a panel from cheap plywood exactly per plans or at least i thonk i have. It really doesn't come close to fitting mainly at the bow end. I have rechecked measurements and positions and they look correct. Any suggestions as to where i've gone wrong?
    Thanks for any help