Rain-gutter Regatta Sail

thingiverse

Here's the sail my son and I made for this year's Cub Scout's rain gutter regatta. Together with an extremely light boat build, he won every race by a fairly large margin. This key design goal of this project was to use the vase print function in Cura to build an extremely light sail that required no extra supports. Our pack rules allow for only one attachment point to the deck and a minimum of 1/4 inch clearance from the sail to any other surface. By utilizing a ridged sail, we shortened the mast to ~3/8 of an inch and kept the center of mass very low in the boat. This resulted in a very light boat the resisted tipping. PETG was chosen since we knew it was going to be beat around and needed to be somewhat flexible. It's easily trim-able with a sharp pair of scissors. Attachment was made with hot glue. The last two years, we've used a vacuum molding machine we made to create sails for the boats using old milk jugs. Those sails were much lighter, but more flexible. It also was a messy to have to create a new smooth buck out of MDF to form the heated plastic if we wanted to change the design. While I did do a majority of the work on the sail design, most of the wood work was done by my son with my guidance. While the build process was very complex, I felt it was importance for him to see the amount of work it takes to have great results. Our pack issues a ~2x7x5/8 piece of cedar planking. The secret we came up with was instead of trying to shape a boat from the provided wood, we used a band saw to slice ~2 mm thick strips. The strips were then sanded flat to ~1.5 mm. 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 was at 0.6 oz. His boat had an extreme advantage, so the rules were updated this year to a minimum of 1.0 oz. Couple coats of paint and we had and extremely tough boat that weighed in at 1.25 oz. If anyone is interested in the stand, I try to link it. My son did that 100% himself in Tinkercad. I helped him add some LEDs to it and he got a chance to learn a bit about soldering.