The Cedar Strip Kayak
February-March 2001
This is an article from WaveLength Magazine, available in print in North America and globally on the web.
To download a pdf copy of the magazine click here: > DOWNLOAD
by Vaclav Stejskal
 |
Laying down cedar strips. |
One cannot help but touch the silky smoothness of the cedar wood kayak hull and imagine paddling in deep blue-green water in search of solitude. It is the spirit of discovery combined with the builder’s artistic impulse, as well as the pure functionality of the wood strip kayak, that inspires passion and stirs thousands of ‘do-it-yourselfers’ around the globe to clean up their basements, garages, and attics and plunge right into construction of their dream wooden kayak.
Some start with only a set of plans in their hands, a few sheets of particleboard and a couple of planks of cedar. The benefit of starting this way is the very low construction cost and perhaps just as importantly, the complete control one has over the selection and quality of wood and other materials. Milling your own strips simply makes it possible to create infinite variety of decorative inlays with greater ease. The craft may take a couple of weeks longer to finish but you will have unquestionably ‘built the kayak completely from scratch!’
Other builders start with a kayak kit because they may not have access to all the machinery needed, or would prefer to dispense with the prep work and tedious dustiness of strip milling. The kit provides all the major ingredients—the full size forms for building the kayak mold, cedar strips, fiberglass, and epoxy. Some manufacturers offer add-ons ranging from Minicel foam seats and foot braces to hardware and varnish. The trade-off with kits is that although they can shave weeks off the project, there is a limit to the selection of strips and epoxies and there is also a higher cost for the prefabricated components.
So, how much does it cost to build a stripper? It really depends, because everyone’s shop is equipped differently and builders‚ standards of quality and material selection vary widely. Let’s assume an average 17.5 ft. kayak uses about three (3/4 inch x 10 inch x 16 ft.) planks of cedar. If you can mill the strips yourself it will come to about $140 to $200 for the wood. Add 2.5 gallons of epoxy, which may go from $113 to $205 depending on the brand of epoxy you choose. The last big item is fiberglass cloth, which averages about $100 at most. The rest of the materials such as particleboard, plywood, varnish, brushes etc. may add another $200 to $300 or so. The average total cost can range from about $500 to $1000. Of course some people will have a lot of tools and useful material lying around their shop, which will reduce the cost considerably, while others may be building from ground zero. Exotic wood, fibers and extras can add a few hundred dollars on top but ultimately, your wood strip kayak will be about half the cost of a similar commercial fiberglass kayak—and of course, the ‘labor of love’ is always free!
The question I am asked the most is: ‘How long will it take?’ An average person can transform a few bundles of cedar strips into a completely varnished single kayak in as little as two months of creative and enjoyable time. Large expedition kayaks and doubles average about three to four months.
|
|
Wood strip kayaks are built year round but the vast majority of builders choose the long dark days of winter and early spring to get into the project. So, if you start in February, both you and your kayak will be ready for your maiden voyage in May or June.
The construction of a wood strip kayak often starts with a table of offsets‚ or ideally with a very accurate set of full size plans. The plan templates are glued on particleboard and the forms are cut out with a fine-toothed jigsaw. These forms or stations precisely define the shape of the kayak and also serve as attachment points for each strip. All forms are arranged on a strongback (spine), which gives the whole structure the kayak shape‚ and necessary rigidity. Unlike a table of offsets, full size plans almost completely eliminate measuring and the mold is aligned visually using register marks printed on the templates.
 |
The project nears completion. |
Once you build the mold, which takes about 3 to 4 afternoons, there is a feeling of confidence and being ‘over the hump’. All energy can now focus on imprinting the kayak with your creative imagination. Laying down the thin splines of colorful and fragrant cedar over the mold is not unlike applying paint on a clean sheet of canvas, and like in a painting, the character of the kayak develops by planning but also by spontaneous experimentation. The occasional mistakes are not hard to undo since the body of the kayak comes together one strip at a time, each can always be removed and replaced later. The actual stripping involves stapling the wood strips to the edges of the forms with long staples. The strips are glued together side by side and their specially shaped edges (bead & cove) interlock together, forming a smooth continuous core. The fact that the strip core can assume almost any smooth convex or concave shape allows the kayak to be designed and shaped with great flexibility. Out of all the homebuilt construction methods, wood strip kayaks can truly boast material-unrestricted, hydrodynamically efficient hull forms.
In order to achieve the desired shape, the wood for this construction must fulfill a few requirements, that is, be light, relatively strong, flexible, and workable. The best and time-tested woods are the cedar species, namely Western red cedar, eastern white cedar, redwood, and yellow Alaska cedar. Other commonly used wood are pine, Spanish cedar, mahogany, basswood, and spruce. Exotic wood is most often incorporated in smaller quantities because of its density. One strip of red Paduk, for example, can weigh as much as 5 to 8 strips of eastern white cedar.
Once the entire mold is stripped over, the staples can be pulled out but the wood core holds its shape now, even without the staples. At this point the surface is very rough, caked up with glue as well as staple holes, which need to be filled with wood putty or other water-soluble filler. Some builders avoid this step by fastening the strips to the forms without staples. The results are often beautiful but the construction is slowed down significantly because each glued strip must firmly set before another strip is added.
Regardless, the surface is still at the ugly duckling stage and needs more work to remove all the smudges and irregularity. This is done at first with a plane or belt sander but the second and most important smoothing step is accomplished with the ‘fairing board’. A fairing board is a flexible piece of plywood about 4 inches x 16 inches with 60 grit sand paper attached to it. It is the only practical tool builders have in their arsenal to bring the kayak surface to a ripple free, velvety smoothness. Once the dust clears, the inlay patterns crystallize and the wood becomes flawlessly smooth and clean. The outcome is often so spectacular that one is completely awash with the resolve to get the thing on the water as soon as possible.
Having finished the woodworking stage, the construction enters a completely different phase, that of high tech composites and modern chemistry. In order to increase the strength of the kayak and to protect the cedar from water, the entire craft is encased in a fiberglass/epoxy skin, which bonds everything together. The term ‘epoxy’ sometimes elicits a nervous reaction in new builders, for it may be associated with the fast setting epoxy tubes in a hardware store. The epoxies used for clear coating are very high quality, harden slowly enough to allow a comfortable pace of work and are relatively foolproof. Many people think of these kayaks as wooden—wood being associated with waterlogged, weak and outdated technology. In fact the more appropriate term should be ‘composite sandwich core kayaks’. Most high performance competition yachts at the Americas Cup have balsa wood as the core material but few would think of these sailboats as wooden. It is the cedar core, sandwiched between thin skins of high tensile skins that makes wood strip kayaks some of the strongest craft in relation to their weight. For example, a 17 foot stripper can beat the weight of the same size Kevlar kayak by 5 pounds—not to mention its heavier fiberglass counterpart.
 |
One of Vaclav’s finished works. |
After filling and sanding, the hull as well as the deck are covered with lightweight fiberglass cloth and wetted out with epoxy. The epoxy, which has the consistency of maple syrup, is carefully spread and smoothed out over the fiberglass, which turns completely transparent on contact with the resin. A couple more filler coats bury the fabric weave and a couple of days later the entire coating turns into a hard plastic shell. All other functional parts of the kayak such as the cockpit, hatches, hip plates and foot braces can now be built. When the deck and hull shells are bonded together, the last fiberglassing task is to ‘wet sand’ the kayak with 180 grit wet/dry sandpaper in preparation for varnishing.
The kayak is basically done and the temptation to take it for a spin is all but irresistible. But before you expose your woodcraft to the full sun, the epoxy coat needs protection against the UV light. Marine varnish provides the ultimate protection, highlights your wood inlays, and gives the kayak smoothness and gloss.
At long last, the day to ‘hatch’ the kayak out of the warmth of the shop is here. By the time you get to the water, people will be giving you thumbs up, but that will do little to dissipate the butterflies in your stomach. Will it float? What if it scratches? Then, before you know it, you are hundreds of meters away from the shore testing the ‘performance envelope’.
So, if you like a little challenge, clean out your basement and go for it. You needn’t be a carpenter to build a wood strip kayak, because most builders aren’t. And it may just be one of the most memorable projects you ever do.
Vaclav Stejskal was born and raised in Prague, and competed for 14 years in rowing as a member of the Czech National Rowing Team. He has worked as a boat builder in Germany building composite rowing shells, and earned a degree in Mechanical Engineering and Material Science at Harvard University. Currently he’s involved in kayak hull design, naval architecture and development of OneOceanKayaks.com. ©