Builders' Forum Archives
Re: SOF kayaks
Posted by Mike on Apr 1, 2006
I do mortise the ribs, and it is a traditional rib to gunnel joint, but I don't do in the traditional way. I use a router to mortise the gunnels, and don't square off the edges of the mortise. Instead I round over the edges of my ribs. This is something that you would want to do anyway, as you don't want sharp corners on the ribs where you will be sliding across them. I also mortise my gunnels for the deck beams. "Traditional" techniques changeover the years. The inuit use what they have available and have even used nails to fasten keelsons and chies to ribs.
I have found that certain finishes work better on different skins. On my canvas skin, I used Elast-o-Seal and Snow-Roof. It worked well with the canves to help keep it from getting too brittle, but the finish does abrade some. In my first polyester skinned kayak I used water-based varathane. It has held up better than the frame has. Water based urethane works very well on polyester. It has been a very durable skin and coating. On my second polyester skin, I used Plasti-Coat tool dip. This kayak is a folder so I wanted an extremely flexible coating. I got it, but this one has an aluminum frame and the aluminum corrodes and the corrosion goes through the skin and coating. It still works okay for occasional use. On my wife's kayak, I used a nylon skin coated with oil-based varathane. It has been okay, but has had some minor chipping. The 8 oz nylon that I used is wonderfull stuff, but I heard that oil-based urethane works better on nylon than water-based. On my last nylon skin, I used the two-part urethane from Spirit Line, and will use it again on any other kayak that I expect to use much. It is wonderfully durable, and is fast to apply. I dyed the skin prior to application of the two-part urethane.
I like using Cris Cunningham's book, "Building the Greenland Kayak" as a guide for building mine. I make my own judgements on a lot of the dimensions now, as I know what I am looking for. His book will give a good all around kayak, and he tells how to modify it for specific purposes. Cunningham has a jig for everything. He based his book off of H.G. Peterson's book that the Inuit in Greenland use as a guide to this day.
That was no me in that photo, it was Greg Stamer. I am able to stand up in that kayak though, and have been able to drop back down to sitting. I just don't have a picture of me doing it. It is an extremely stable 17.5'x20" kayak. It has a very flat bottom, with virtually no flare, so the chines are almost 20" wide. It also has almost no rocker and a full length keel rubrstrip. It is an interesting kayak, quite boxy, but rolls well, goes extremely straight, except in currents, and carves turns reasonably well. It is derived from George Putz's book, "Wood and Canvas Kayak Buiding". This method works okay for those afraid of steam bending, but does not produce as durable of a kayak frame as more traditional methods.
Check out the pic below of Freya at SSTIKS this last year. There are getting to be more and more stupid human tricks at SSTIKS.
The inside of my brown SOF
In Response to: Re: SOF kayaks by SOF Building Techniques on Apr 1, 2006