Strip Plank Construction
CONSTRUCTING A STRIP PLANKED CANOE OR KAYAK
There is nothing quite like a strip planked canoe or kayak for sheer beauty. Such craft are always much admired with their planks of contrasting coloured Cedar beautifully varnished.
By using the strip planked method, we can produce a lovely round bilged hull shape without many of the tools and skills required for traditional round bilged construction. Basically this method entails marking and cutting out mould (sectional) shapes from a cheap material like chipboard and erecting these upside down on a simple strongback. The hog (internal wood keel), internal stem and stern members/moulds are then positioned onto the strongback. For canoes and kayaks, the central hog is often omitted relying solely on the planking for longitudinal strength
Once this "jig" is completed, the edges of the moulds, hog etc are beveled to suit the planking which is in the form of narrow parallel strips of wood - usually Cedar. The Cedar strips are temporarily fastened to the moulds but permanently glued to the hog and to each other. Once the hull has been covered with the Cedar strips, the Cedar is cleaned up and then sheathed. Cedar is quite soft and therefore needs sheathing whilst other timbers may not.
The sheathing is often woven glass cloth in epoxy resin which allows the natural wood to show through and gives the Cedar a protective hard outer surface. On larger craft, the Cedar may be overlaid with wood veneers often laid diagonally. Any outside keel strip or bilge runners are then secured in place over the sheathing.
Once up the right way the inside of the hull is cleaned up and may be sheathed. What you now have is a hull "shell" which is much lighter than a conventional carvel planked hull but just as strong and ready for fitting out.
There are many variations in the method and different types of strongback may be used - see our Manual of Strip Plank Construction Techniques for further information.
THE STRIP PLANK METHOD OF CONSTRUCTION
The following example of Cedar strip plank construction are of one of our Prospector strip plank canoes beautifully built by John Dixon. Note for further photos of a simple canoe building jig and an example of our Sealion kayak being built, go to the Photo Gallery page.
A. Although the planking here is well under way, you can see the chipboard moulds which are simply sectional shapes erected upside down on a simple strongback - our plans give full-size mould shapes and details of the jig.
B. In the simplest construction the bow and stern shapes are simply defined by chipboard patterns (again these shapes are given full-size on our plans) - in this case the patterns have been reduced in size by the thickness of a laminated internal stem piece - this can be seen in the above photograph being glued up and held in place by G cramps to the stem pattern.
C. The photograph above gives a closed view of the bow (or stern) of the canoe showing the laminated inner stem temporarily attached to it's chipboard pattern which in turn is fastened to the fore most mould.
D. This photograph shows the planking continuing up around the bilge and starting to meet the hog (inner keel strip) to which it will be glued - often the hog is omitted and the planks are simply glued edge to edge along the centreline but the hog gives a stronger and easier join - the planking is glued edge to edge and temporarily fastened using nails, screws or in this case, staples to the edges of the moulds. The staples have been used over tough strips of plastic (yellow in the above photograph) so that they do not bruise the soft Cedar and making them easier to remove before the planking is cleaned up.
E. The finished Prospector - note the run of the planks - they are horizontal and do not follow the sheer/gunwale line as they may do in bigger boats - often the curve would be too great for the planking to bend round unless it was very narrow - so the swept up ends are simply planked in ever shorter lengths to fill in the 'triangle'.
F. Both inside and outside have been sheathed in a lightweight glass cloth in epoxy resin leaving a clear finish. Note how the breasthooks at bow and stern have been strip planked too allowing John Dixon to produce a beautifully crafted canoe. With the sheathing, l normally recommend the 'dry' method - the sanded wood surface is 'primed' with epoxy and this is allowed to cure. After a light sanding and cleaning down, the woven roving glass cloth is then laid over the hull dry and epoxy resin is applied over the top and worked through the cloth to the wood below removing and trapped air - this allows the builder to work at his/her own pace. The alternative' wet' method involves applying resin over the entire 'primed' surface, laying the cloth on and working to wet it out before the resin cures.
G. Beautifully finished, she is seen here with a simple rig allowing her to be rowed.
H. Some builders do not like so much varnished wood showing - hers is the 16' Explorer and Strip Planked Pete both by Alec Jordan of Jordan Boats with varnished interiors and pained exteriors.
There are many variations in the method - see our Manual of Strip Plank Construction Techniques for further information.