One of the main reasons I’ve wanted a CNC router, is so that I can build kayaks. I’ve been interested in kayak building for quite a long time, and a few years back I decided to build one. I choose the skin on frame construction method because it is very good strength to weight ratio. I cut the forms of my first one with a reciprocating saw, but I knew there had to be an easier way.
Many boat plans come as a table of offsets, basically a table of coordinates that when plotted, give you a cross section of a boat. Plot out a few cross sections, and you have forms or ribs, depending on the style of construction.
For my design, I used plans from Yostwerks.org, the Sea Tour 17 Exp.
HAB = Height Above Baseline
HB = Half Breadths (centerline to the outside edge.
Starting one section at a time, you mark the keel at the measurement provided on the center line. For chine one, you measure out from the centerline the distance specified for HB, then up for HAB. Once you have all the coordinates plotted for one section, just connect the dots, and you have half the profile of one section. I’m drawing this up in Fusion 360.
Here’s a cross section.