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.

Optimist Pram - finishing the frames

With this third video we put the frames on the strongback and get ready for the keelson and stringers. The frames go together quickly after making sure the height is correct off the strongback. Following the CABBS' strongback plans to the letter would have made things a bit easier, but we were trying to save on wood and ended up reconfiguring just a bit. As you can tell from the video, we are using old, recycled wood whenever we can because most of the pieces will be painted and hidden from view.

Building the Optimist dinghy - frames

Winter is flying by, and we are diving into our three-boats-at-once project. We have spent some time getting to know the CABBS plans. It's helped to have found some pretty nice images of other folks working on their Optimists. Nothing like a picture to make things clearer.

Here is where we would like the project to be the next time we get to work on the Optimists:

Pictured below in red are the frame stations that we are working on in the accompanying video, and how they will support the other members. We have completed the bow frames (1) and attached the bows to the strongback. The bow must be angled back at 22 degrees as can be seen below. The rest of the frames (2 and 3) are perpendicular to the strongback.

If any readers happen to stop by and read this post and watch the accompanying video, feel free to leave a comment about the "real" way to build these prams. My brothers and I have sailed boats and fixed-up wooden boats, but we've never attempted to build any from plans. This has been a fun and challenging experience so far.

You may notice from the video that we have been using scrap lumber. We have a lot of odds and ends of wood lying around, so to save on cost we have used old lumber as much as possible. We need these boats to last about ten years - we will see...

Building the Optimist Strongback

The least complicated part of boat building is the strongback or base with which to attach the stations or molds. Clark Mills designed the Optimist with only three simple molds - bow, mid-frame, and transom. This strongback gives the builder a good base to attach the three cross-members that will set the precise distances for the bow, mid-frame and transom.


We are building three Optimist at once, so here is a quick look at our three strongbacks using the CABBS plans: