I have made a couple kayaks and canoes. I wanted to try to make something similar to Point 65N’s modular kayak. https://kayaks.point65.com/
*Edit: I have 2 of these that I built laying around. I thought about cutting and capping at the arrows just for a proof of concept and then coming up with a way to join them. I thought about doing 2 long dovetails have them slide together but didn’t know what to do with the gap.
