Dave Isbell has been building the frame of my new Skin on Frame (SOF) kayak in his basement for a few months now. Except for an occasional email asking me for another measurement I really haven't heard much about it. And I've been so busy working on the house I haven't asked. But I asked him to email me as soon as the frame started to look like a kayak.

This is best described as an experimental kayak design. He's started with the design of the Guillemot Mystery then modified the hull to work within the design constraints of a skin on frame. Marek provided an excellent summary in his kayak blog. The Mystery is designed to be built using strips of wood. A skin of frame is built by using long intact pieces of wood to build a skeleton or frame. Then the frame is covered in canvas and painted. The earliest remains of these SOF kayaks have been found in Greenland where wood is scarce. And this makes sense. A frame kayak covered in canvas (or seal skin) would use considerably less wood than a kayak built entirely of wood. The early Greenlanders worked with what they had. Although speed is always a good characteristic, most greenland kayaks weren't designed for speed. They were designed for ocean hunting of seals and they needed to be easy to roll. The waters around Greenland are deathly cold. Thus the deck was low and hugged the body tightly. Getting into a traditional greenland kayak is not unlike putting on a tight fitting pair of jeans. You wiggle in. While these design characteristics worked well for a stealthy ocean hunter they don't work well for speed.


So the first design modification we made was to raise the fore deck. The fore deck looks approximately liked the scaled drawings on the Mystery, but scaled down to fit my 5'1" frame. Because I also want to be able to roll this boat in the event of a capsize we made the deck as low as possible while still providing room for my knees. The sides taper down and the idea is that I will pad out the sides so that I can roll the boat with my knees pressed against the sides. The back deck was designed to be flat which will also make the boat easier to roll.

The beam of the boat is a maximum 18 inches, although we're expecting the waterline beam to be around 14-15 inches. The shape of the kayak is Swede-form, which means that the maximum breadth of the kayak is aft of the cockpit. Also the bow of the kayak tapers down sharply from the cockpit to allow the paddle an entry point close to the center of the boat. In working through the design of the boat with Dave I learned a lot about the tradeoffs one has to make when designing a boat. Greenland style boats have lots of "rocker". Rocker refers to how the keel of the boat sweeps up at the bow and stern. A boat with a high amount of rocker is easy to turn and maneuver. But it slows the boat down. For maximum speed you want a long waterline. So Dave designed the boat to have almost no rocker. Because of the flexibility in the wood which provides the framework for the kayak, we think there will be some rocker introduced by the weight of the kayaker.

Everything is a tradeoff. I'm expecting that my Huki S1-A surfski will still be faster than this SOF kayak but taking the surfski out in open water still scares me. Knowing that I can roll this boat if I have to will give me incredible peace of mind. To see more pics, click here.

-Susanita