STRIPPLANKED BOATS
Elegant, classic, timeless
Wooden canoes in strip construction are light and robust boats with a high utility value and an elegant appearance. The composite construction of wooden strips and fiberglass reinforced plastic does not represent a compromise between appearance and weight advantages, but is usually even lighter than other materials in the canoe industry. Depending on the woods and fabric weights used, canoes weighing far less than 20kg can be realized.
The Strongback
the foundation with which everything begins. Stable, level and solid.
Every construction of a strip canoe begins with a strongback. It is the shaping framework on which the strips are placed and form the hull. Since the formgiving malls will be attached to the slipway and the symmetry of the canoe depends on it, it should be aligned straight and also be very stable. The malls are removed again after the canoe is built and can be reused, just like the strongback.
STRIP PRODUCTION
What to say about the production of 70 canoebuilding strips: after that you will be familiar with your saw
The ideal wood for a wooden canoe in strip construction is Red Cedar (Thuja plicata), because it is very light, has an insanely beautiful appearance and is also very easy to process. Another advantage of the wood is the aromatic scent it gives off when sawn, planed and sanded. However, when processing this wood, a filter mask should be worn urgently, as the dusts are harmful to health. Several hundred meters are covered on the saw and router table alone in the manufacture of these 6mm thick, approximately 20mm wide, concave and convex milled strips. Finally, the sawed strips are provided with a concave and a convex milling at the side edges, through which the strips can also be glued at an angle.
Planking
Strip by strip, with or without staples. In the end, dexterity is required when the hull is closed at the keel.
A basic decision should be made before attaching the first strip: "with or without staples?" Stapling the strips to the hulls has the advantage that the hull is completed more quickly, since strip after strip can be attached without having to observe the drying times of the glue. Visually, however, this method has the disadvantage of leaving bands of small staple holes at even intervals on the hull later. Better, but also more complicated, is the construction without staples, for which there are countless, more or less awkward approaches. Instead of stapling, I recommend placing screws in pre-drilled holes only where necessary, and closing the screw holes later with wooden dowels. Screws because a few screws can absorb more forces than many staples. A few irregularly positioned wooden dowels are almost unnoticeable on the finished canoe and also give the hull a kind of traditional look like that of clinker boats. Glue residue should always be removed promptly with a damp cloth, as dried glue will later block the sandpaper and make the sanding process more difficult. Finally, an oval hole is created towards the keel, which must be closed with strips that become shorter and shorter. The last strip is traditionally doused with whiskey as a "whiskey plank". When building a strip kayak, the hull and deck are made on the same strongback, but the two resulting shells are sanded and laminated separately before later being glued together to form the finished kayak. Gluing the two shells together through the small cockpit opening is very challenging and requires a lot of dexterity.
Sanding Work
Either you love it or you hate it. Whether you have the necessary endurance and patience, you will know after the first days at the latest.
Sanding takes the most time of the entire construction of a strip canoe and requires patience from the canoe builder. However, the overall beauty of the finished canoe depends largely on the quality of the sanding work, so you should take plenty of time here. The closed hull remains on the strongback. A random orbital sander is well suited for a rough first sanding on the outside. It is important to work evenly over the entire surface. To remove glue residue, one is inclined to edge the sanding disc, which should be avoided at all costs, as this can cause deep dents that are still visible on the finished laminated canoe. Finishing sanding is not too fine with 120 or 180 grit, so that the epoxy resin will later find a structure to adhere to. The sandpaper is attached to a large, not too soft sanding pad that conforms to the contours of the hull. Sand by hand in the direction of the grain of the wood until an even surface is achieved. The best way to check the progress is to shine a spotlight over the hull. Finally, the hull is wiped once with a damp cloth so that the wood fibers stand up. These are removed in a finishing sanding and the hull is ready for lamination. After laminating the outside, the inside is sanded. Here, the random orbital sander can be used carefully on the bottom. Otherwise, the inside of the hull is mostly handwork. Depending on the radius, you should look for different pads for the sandpaper here, which also produce an even sanding in the curves.
From Wood to Glass.
Laminating
by applying a layer of fiberglass reinforced plastic, the delicate wooden hull becomes a robust and usable canoe.
Put on your gas mask, overalls and gloves.... here we go!
Laminating a wooden hull with fiberglass-reinforced plastic (GRP) is one of many composite construction methods in boatbuilding and has become very important in modern canoe construction. You realize how delicate and fragile a canoe hull is once you take the raw wooden hull off the molds: an estimated 20% of the final stability comes from the laminated hull, 80% from the GRP. So the wood is the component that gives the canoe its shape and appearance, but not its stability. A fiberglass fabric is now placed on the cleaned hull and smoothed out with a small hand brush. The fabric should be handled with cotton gloves so that it does not get grease spots to which the resin will not adhere later. Fabrics in twill weave are particularly suitable for wooden hulls, as they can be laid over contours better than fabrics in plain weave. An epoxy resin with a long pot life is used so that there is enough processing time to saturate the fabric. Work is done from one end of the hull to the other. The resin is applied with a large brush and allowed to soak into the wood for some time. For this purpose, the resin should not be applied too thinly, otherwise dry spots may occur if the wood is very thirsty. Once the wood is saturated, carefully peel off and dispose of excess resin with a plastic squeegee. The correct pressure and angle of the squeegee is critical here. If too little pressure is applied, too little resin is removed and the fabric could float in the resin, creating bumps that you can grind into later. If too much resin is removed, the fabric will be too dry and white spots will appear in the laminate, which will also be visible on the finished canoe.
Fillcoats
Night shift in the canoe workshop. The laminate is built up in many thin layers. Now the resin is your employer and decides when you are allowed to sleep.
The first laminating pass serves to impregnate the fabric and ensures adhesion of the fabric to the wood. After the excess resin has been removed with the squeegee, the fabrics structure is visible again, which must now be filled with several "fillcoats". The time to apply the first fillcoat is when the resin is still tacky but no longer pulling threads. Do not test this with your bare finger, but with a nitrile glove! Fillcoats can be applied slowly with a solvent compatible foam roller. If you roll too fast, small air bubbles will remain in the resin, which you can remove promptly and carefully with a hot air gun. Apply as many fill coats as necessary until a sufficient layer of resin has built up to allow later sanding. Do not sand into the fabric, as this will leave white spots. You can find more tips on processing GRP and work safety in the blog.
Anticipation
The installation of the seats brings you closer to the water. You feel that it will soon start and the first trip with your self-made canoe will reward you for all your efforts!
Visible now is an almost finished hull. After all the hours of sanding and working with resins and gas mask, you would just love to test paddle the half-finished hull, but the interior parts are still missing. A kayak hull consists of two shells that must be glued together to form the finished kayak. Then the seat, footrests and hatches are installed. In the canoe, the gunwales are attached to the coaming and joined in the center of the boat by a thwart, which gives the hull its rigidity. The seats are installed and finally the hull can be varnished. During the first paddle trip it suddenly happens: the first scratch ... the canoe is now finished!
is it your project?
In terms of craftsmanship, the strip construction method is extremely demanding, as not only precise work is required when planking, but also a clean finish when laminating and varnishing the hull. In addition to the necessary craftsmanship, many jobs also require a lot of stamina when sanding the hull over large areas. The result, however, justifies all the effort: paddling your own strip canoe for the first time is simply indescribable.