I’ve had an itch to build another skin-on-frame kayak for some time now. I try to apply all the lessons I've learned from my previous experiences into each new kayak. If you could examine them side-by-side you might see a clear progression, an evolution as each kayak uses what worked well in the previous version, but also experiments with something different.
After building and owning a wide variety of kayaks, I still find myself returning to skin-on-frame kayaks for a number of reasons. First of all, they are customizable. Back when I built my first kayak, there was not a lot of variety in designs commercially available. Kayaks typically were made to carry a ton of gear and accomodate guys who were 6 ft tall and 200 pounds. I wanted a kayak that had a snug cockpit that would fit me well for rolling. In traditional Greenland kayaking, the kayak is designed anthropometrically, that is, according to the dimensions of the individual paddler. Dimensions are measured in arm spans, cubits, length of feet, size of fists, and width of fingers. You really don’t even need a ruler to build a kayak (although of course I still like to use one, to calculate how much wood I need and accurately compare dimensions with existing kayaks). Many traditional Greenland kayaks were built so tightly that you didn’t really sit in them as much as you wore them. Getting into one was like slipping on a pair of tight jeans.
Secondly, skin-on-frame kayaks can be very lightweight and easy to carry. Since I kayak alone a lot, I don’t have anyone around to help carry all my stuff. Having a lightweight kayak makes a huge difference for me to be able to get out on the water easily and quickly. It's a real pleasure to carry one on your shoulder from the car to the beach. Don't underestimate the importance of this! For me personally, it meant getting out on the water a lot more often and spending more time developing skills. Carrying a heavy kayak by yourself also risks back injury. I know from experience! On the water, less weight may not be as important as on land, but it translates into less wetted surface area and less drag, as well as greater “responsiveness.”
Lastly, skin-on-frame kayaks are quite strong despite their light weight. There are plenty of lightweight kayaks available commercially, but they are usually made out of expensive carbon fiber or other exotic composite materials and their price reflects this. You wouldn’t want to risk having them fall off the roof of your car, which is exactly what happened to my skin-on-frame kayak. After paddling on Lake Union in Seattle, I threw my kayak on my car rack, but forgot to strap it down,. While turning a corner it rolled off my car onto the middle of a major arterial in downtown Seattle. I had to stop traffic while I picked it up. Fortunately, it survived without a scratch!
Strength comes from the flexibly of the frame. Since the parts are all pegged and lashed together, the frame flexes. It's a balance of forces: the frame resists compression while the skin resists tension. The nylon skin, coated with polyurethane, is incredibly tough. I've unsuccessfully tried to punch through repeatedly with a Philips screwdriver. Of course, comparing it to fiberglass is an "apples to oranges" comparison. Nylon will resist blunt force well, like repeated pounding with a hammer, but will easily be sliced with a razor. Fiberglass can't be cut with a knife but won't do well against a hammer.
Traditional skin-on-frame kayaks are often designed to be used purely as very low volume rolling kayaks, but there is no reason they can't be designed to carry a lot of gear. They are durable enough for serious expeditions too. Primitive skills experts Kiliii Fish and Phoxx Ekcs have used them loaded with gear for month long trips along the exposed coast of Vancouver Island, for instance.
My idea for Katya’s kayak was that it would serve as a sporty daytripper, built as light as possible to make it easy for her to carry on her shoulder and throw on top of her car, as well as hang from the ceiling in her living room. It would be easy to roll but not a super low volume “rolling kayak”, with a comfortable cockpit with a large opening that will fit a standard sprayskirt.
To get the weight down, I choose Western Red Cedar for the frame and Alaskan Yellow Cedar as the bending stock for the ribs and coaming. Although not as strong as oak — a popular choice for ribs— yellow cedar is much lighter. I spaced the ribs and deck beams as far apart as I could.
Although in the past I preferred the smaller “ocean” cockpits for their traditional look and tight fit (very important for a rolling kayak), small cockpits make it difficult to get in and out quickly in rough conditions or surf, and difficult to get in and out from a dock. Plus, they require having specialized gear --the tuilik (traditional paddling jacket) and akuilisak (spray skirt). I wanted Katya to be able to use her existing, standard gear and avoid her having to get a custom skirt.
Another one of my goals was to build this kayak as simply and efficiently as possible. It can be a real challenge to balance cost, time, and quality in a boatbuilding project. For instance, I usually get clear 16 ft cedar boards from my local lumbar yard. They are a little pricey, but I save time by not having to scarf a long board out of two less expensive shorter boards.
Some kind of glue is needed for scarfing and for assembling the coaming, and possibly for laminating curved deck beams (the masik) and repairing cracked ribs. I like to use the polyurethane Gorilla Glue rather than epoxy because you can use it right out of the bottle instead of having to carefully mix up epoxy. If you already have epoxy lying around though, there is no need to avoid using it.
Dozens of recipes for bending ribs have been published online. Some people recommend soaking the rib stock for a few days before steaming them. Some think soaking doesn't makes a difference. Success depends heavily on what species of wood you are using, how green it is, how straight the grain is, and your own experience and bending technique.
In the past I steamed my ribs but this time we followed the advice of baidarka builder Mitch Poling and boiled the rib stock. I made a narrow metal tray, just long enough for the ribs, out of roof flashing and put it on top of a couple electric stoves. We filled it with water (preheated in an electric kettle to reduce to time to get it up to temperature) and let the rib stock sit, boiling it for 3 hours. Of course, I had to check to see how well the wood would bend after only 2 hours. Two hours was definitely not long enough and 3 hours was optimum. It sounds like a long time to sit, but when you consider that you can boil all the ribs you need at once, and that you can keep them in the hot bath and they will remain flexible until the moment you need them, it might take just as long as steaming, depending on how many ribs you can steam at once and how long you need to steam them.
I didn’t have a tray long enough to boil the coaming, which is made out of 6 ft lengths of yellow cedar, so I steamed it inside a PVC pipe. It was flexible after 40 minutes, without presoaking.
When bending the ribs, I think it's important to use a large leather belt as backing, and pay attention to how the wood feels as it bends. Forcing the wood around a form doesn’t seem to work well for me. I think it is because I don’t get any feedback from the wood and end up breaking a lot of ribs. I perfer to bend it freehand, so I can feel how the easily the wood is bending. That way I can adjust where and how I apply pressure depending how the resistance feels.
Some builders put in a lot of work into finishing the frame. On principle, I try to avoid using any sandpaper. After all, do you think the Inuit used sandpaper? Well, maybe it's just laziness. I think it's fine to finish the surfaces with a sharp plane. It will be entirely covered up by the skin anyway, so who is ever going to see all of your fine woodwork? No one will unless they get really nosey and stick their head inside.
I don't bother oiling the frame. Although I do like how oil brings out the color of wood and makes it smell good, but I am not aware of any good evidence that oil adds much protection against rot over time. It is also another step that adds at least couple days waiting for the oil to dry. With regular use the finish will fade rapidly anyway.
After the frame is finished, I always feel that it is such a shame to cover it up with the skin. This is a good time to stop, admire your work and take pictures.
Katya came up with the idea to buy a bunch of helium-filled balloons and tie them to the frame, and photograph it as if it were floating off into the sky. The idea was to emphasize the lightness of the frame. We spent a lot of time trying to get this right and it took most of a day. She picked up twenty helium-filled balloons at the local grocery and drove them all out to the boat house. Although the frame is exceptionally light, it would take a lot more than 20 balloons to lift it off the ground!
We scouted around to find a good location and decided to go to the waterfront on Commencement Bay. She tied the balloons to the bow and while holding the kayak raised the bow and had me snap the picture. But as soon as she raised the bow the ties slipped and the balloons flew away! So we loaded up the frame on her car again and drove back to buy another 20 balloons. When we were done with them, we gave the balloons away to kids playing on the beach.
Skin choice is another potential area to save a little money but I don’t recommend going cheap here. You don't want the skin to tear, leak, get stained with mildew, sag, or shrink too much and distort the frame. And reskinning a kayak is a lot of work. I have been using Corey Freedman’s junior ballistic nylon and two-part polyurethane (“Goop”) skin kit, for all of my kayaks, but have occasionally thought about trying canvas sealed with oil-based house paint or varnish. Many professional builders consider Corey’s method to be the gold standard for kayak skinning. And from what I have heard so far about the quality and durability of canvas skin, I think I'll stick with Corey’s method for now.
In the past I dyed the skin with acid dye prior to sealing it with polyurethane, but now Corey recommends mixing the pigment with the resin rather than dyeing the skin. This saves some extra steps, and I think might avoid the potential problem of the dye inhibiting the binding of the polyurethane to the nylon, which some people have suspected might be occurring in cases of early de-lamination seen especially with the darker pigments in high wear areas.
Most of the cost of building a kayak (or any boat for that matter) is going to be your own time and labor. So generally, it doesn’t make a lot of sense to skimp on materials to save a little extra money. I would rather spend a little more for materials that will give the most durable result.
Our final result is a sporty, very lightweight (just under 24 pounds), comfortable kayak. I like the shorter length (my current skin-on-frame kayak is 19.5 ft long!) She seems to glide effortlessly through the water and is very manuaverable and well-balanced in the wind. I found it easy to side scull and roll but the larger cockpit opening make it harder to get a grip on the kayak with your knees. I am considering gluing a layer of minicell foam right where the knees touch the skin to make it grippier. I'm already thinking of how I will build my next kayak, based on the hull shape and techniques we used with this one. For now though, it's time to go paddling!