Rain-gutter Regatta Sail

thingiverse

Here's the sail my kid and I built for this year's Cub Scout rain gutter regatta. Working together with an incredibly lightweight boat design, we dominated every race by a significant margin. The key goal of this project was to utilize Cura's vase print function to create a superlight sail that required no additional supports. Our pack rules specify only one attachment point to the deck and at least 1/4 inch clearance from the sail to any other surface. By employing a ridged sail, we shortened the mast to ~3/8 of an inch and kept the center of mass extremely low in the boat. This resulted in a very lightweight boat that resisted tipping. PETG was chosen because we knew it would be battered around and needed to be somewhat flexible. It's easily trimmable with sharp scissors. Attachment was made using hot glue. Last year, we used a vacuum molding machine we built to create sails for the boats from old milk jugs. Those sails were much lighter but more flexible. We also had to create a new smooth buck out of MDF to form the heated plastic if we wanted to change the design, which was messy. I did most of the work on the sail design, but my kid handled most of the woodworking with my guidance. Although the build process was complex, I felt it was essential for him to see how much work goes into achieving great results. Our pack provides a ~2x7x5/8 piece of cedar planking. The secret we came up with was using a band saw to slice ~2 mm thick strips instead of trying to shape a boat from the provided wood. We sanded the strips flat to ~1.5 mm, and he was able to do this (with supervision) using a simple fence. We worked together to design the side profile of the boat, then he cut it to shape using an Xacto knife and a metal straight edge. Using thin CA glue, we joined the edges until we had a hollow hull. We 'painted' the rest of the raw cedar in CA glue to harden and strengthen the wood. Last year's thinner, lighter, and much weaker boat weighed 0.6 oz. His new boat had a significant advantage, so the rules were updated this year to a minimum of 1.0 oz. A couple coats of paint made an extremely tough boat that weighed in at 1.25 oz. If anyone is interested in the stand, I try to link it. My kid designed it 100% himself in Tinkercad. I helped him add some LEDs and he got a chance to learn about soldering.