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By Kellan Hatch – Salt Lake City, Utah - USA

Tom Yost's Amazing Cornucopia of Free Kayak Designs

Clayton Thomas' wood frame Nikumi baidarka

If you’re looking for a sturdy ultralight kayak or a portable folding kayak that doesn’t cost an arm and a leg, or if you’re just jonesing for a genuinely pleasant and rewarding building experience, you need look no further than Tom Yost’s amazing Yostwerks website: yostwerks.com.Take a peek.  If you can’t resist the prospect of building one of Tom’s designs, or if you have already given into the temptation and want to share with others, there is a newly hatched support group for incurable Yostheads at:  http://groups.yahoo.com/group/Yost-Skin-On-Frame-Boats/

A skin-on-fame kayak is an artful blend of ancient and modern technologies. There is, in my opinion, nothing more elegant on the water. A skin boat is a delight to paddle. There is something satisfyingly organic about the way if feels on the water. Most SOFs are designed to flex as the waves roll under and around them, which is one reason they are so resilient; the flexing allows forces to be distributed evenly throughout the frame.

I am in the process of building my third skin-on-frame boat and the second designed by Tom Yost. I can't remember when I have had more fun building anything, with the possible exception of my first Yost kayak, a Sea Tour 17, which has a frame of aluminum tubing and HDPE (high-density polyethylene) plastic covered with vinyl-impregnated polyester fabric. I built it with the intention of making it collapsible so I could carry it in a duffle bag and possibly check it onto an airplane, but I never quite got around to cutting it up for folding.

The Frame of my Sea Tour 17 R is made from aluminum and HDPE

The new project, a SeaTour 15 EXP, has a wooden frame that will be covered with a 12oz Nylon saturated with urethane. I have just completed the frame and am about to start laminating the cockpit coaming.

My Sea Tour 15 EXP frame nears completion

 

...and skinned with 8 oz. Nylon

When people first encounter skin-on-frame (SOF) boats they sometimes make the mistake of assuming that they are fragile. The truth is that they are bewilderingly tough little craft, especially considering how lightweight they can be. Consider the inventors of skin-on-frame kayaks, the native Inuit of the northern arctic regions. They have fished and hunted for centuries from their featherweight craft made of driftwood, caribou antlers and sealskin. Greenlanders, unexpectedly blown out to sea, have even crossed the open ocean as far as the British Isles.

While you wouldn't want to drag your skin boat across a field of razorblades you need not fear any forces that a kayak encounters in normal use. If you doubt this, drop me a line and I'll send you a video of a builder attacking one of his Nylon skinned boats with the pointy end of a claw hammer.

Terry Reed used a sewn Nylon skin for his Sea Tour 15R and sealed it with 2-part urethane

SOF kayak frames fall into two general categories: traditional and fuselage construction. A traditional frame is more or less true to the original Inuit pattern. Building a traditional frame can be quite involved and requires mortising, steam bending and careful fitting of close-tolerance parts. The fuselage style frame hearkens back to the early days of aviation and employs plywood cross sections connected with longitudinal softwood stringers. This is the structure that Tom uses and it is much easier to build than a traditional frame. There are several techniques you can use to assemble a wooden frame: it could be screwed and glued, pegged or lashed together with artificial sinew.

Hubert Schreier's Sea Tour 15 frame is lashed together with artificial sinew

You also have a wide variety of skin choices, depending on your needs and budget and whether or not you want your kayak to be foldable. Chuck and Sandra Leinweber have been paddling their canvas skinned boats for years. They used house paint to seal the canvas. And let us not forget Franz Romer who crossed the Atlantic in a canvas kayak in 1928, or Hannes Lindemann's 1951 repeat performance in a folding canvas Klepper. A canvas skin is heavier and more fragile but less expensive than other options. Many of Tom's boats, particularly the folding designs, are skinned with a commercially made vinyl-coated polyester. Or you can sew your skin on in a more traditional style with extremely tough modern fabrics such as ballistic Nylon or heat-shrinkable Dacron in place of the traditional seal skin. Tom and a number of his acolytes have even skinned their kayaks in transparent vinyl, which makes for a sexy see-thru boat.

Tom's Sea Rider sports a transparent vinyl skin

Tom's kayak frames come in three varieties: folding boats with aluminum/plastic frames, non-folders which can be made of wood or aluminum, and inflatables which employ a very minimal aluminum frame with inflated sponsons for shape and buoyancy.

A sample page from one of Tom's tutorials illustrates how a folding aluminum frame breaks down

These ingenious inflatables are extremely portable. They weigh in at around 20 pounds and fold up into a bag that you can sling over one shoulder. Tom straps his on his motorcycle. Another advantage of the inflatable design is that the minimal frame is assembled through the cockpit opening, eliminating the need for zippers.

John Van Buren paddles his semi-rigid inflatable Sonnet 16

Tom Yost has designed dozens of skin-on-frame boats ranging from children's kayaks to sailing trimarans. Paddlers at the Greenland Kayaking Competition have won events using Yost folders that they carried with them on the airplane. Any of Tom's designs can be built either rigid collapsible. He estimates that something like 1000 kayaks have been built to his plans on every continent (yes, that includes Antarctica). That is impressive, but just as impressive is the fact that Tom provides his plans, along with detailed building tutorials absolutely free of charge. A pure labor of love. A link to Yostwerks is also now available on the Duckworks Plans page:

http://www.duckworksmagazine.com/r/plansindex/kayak.htm

If this article has piqued your interest, check out Tom's website. If you want more information or if you decide to take the plunge - or if you are already a Yost builder willing to share your expertise, please join us at the newly hatched Yost Skin-On-Frame Yahoo Group:

http://groups. yahoo. com/group/Yost-Skin-On-Frame-Boats/

This is a brand new forum where you can ask questions, show your work and share your adventures. We will discuss the construction and use of Yost boats as well as all flavors of skin-on-frame craft.

Brian Lipcott's folding Sea Otter is more portable and far less expensive than commercial folding kayaks

 

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