After an exciting summer of sailing and sailboat racing, we are returning to the Optimist project. In the effort to make these boats as inexpensive as possible we have purchased luan plywood to sheath the hull of our boats.
Our decision to use luan was based on information given to us by John Bridges who has been building Optimists since the 1960s. He has built Optimists of luan and they have been in service for over 5 years. That is longer than we will probably need the boats.
We will also be stacking these hulls after sailing them - leaving no water in them to cause problems. Additionally, we will be priming our hulls with CPES (clear penetrating epoxy sealer) as a way to be sure that the absorption of water is slow.
Today, we worked on the hull sides.
Working on three boats requires 5 sheets of plywood to complete all the hull skins.
We ripped two full sheets on 16 inches the long way. This gave us 6 strips to use as hull sides.
Temporarily attaching one side to trace the contour, we removed the piece and cut a bit proud of the pencil line.
We checked to see if the template piece fit all three hulls - it did.
Using Locktite PL Construction adhesive, we laid a bead of glue along the chine and bow/transom about half way down the hull.
Starting at the transom we worked forward placing screws about 5 inches apart.
We worked in a zig-zag pattern of top then bottom as we worked forward to be sure not to pucker or buckle the plywood.
For quite some time weve 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. Im not sure it is necessary to wait that long, but we had the time to let it dry and didnt 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 wasnt 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.
Adding the hull side panels was pretty straight forward. We hand-planed the chine logs so that they would be level along the bottom of the boat. We used 3/4" stainless steel woods crews from Jamestown Distributors. I set the width for the screw holes by spreading my index and pinky fingers wide apart and making that distance on the chine and stringer attachment points. We used about 50 wood screws per side panel. Liberal amounts of PL Construction Adhesive were applied along the chine and stringers and things went well.
