Glued Lap Construction Overview
Glued lap construction is comparable to traditional lap strake construction. The primary difference is epoxy takes the place of traditional rivets or copper nails to join the planks lengthwise.
I characterize glued-lap construction as the thinking person's boat building method. Relative to stitch and glue or wood strip methods, glued lap requires much more mental gymnastics. The end result can be stunning.
One ideally has to truly desire the look and feel of traditional boat building to commit to this method.
In my opinion, based on experience, I would consider this method rather demanding for first time builder or amateur.
With patience however and with several very useful books, I had three books when I built the Iain Oughtred MacGregor. I made use of each book very frequently.
Glued lap requires station forms to be created and a strong back to support them. It has this in common with the wood strip method.
After the station forms are in place, one attaches battens per the designers plan to simulate plank landings where they will overlap. These are in turn used to take the dimensions used to create the planks
Plank lands are planed. This is the area where planks overlap. When ready this area is covered with a thickened epoxy slurry, and clamped along its length. Once cured the clamps are removed. In general, the boats are not reinforced with glass.
Like traditional small hull construction, one must loft and create the keel, bow and stern sections.
The photo below shows the lamination of the bow and stern pieces which are joined to the keel laid on the stations.
It is conceivable that your life may depend on the strength of your boat and cutting costs in materials is the wrong place to save money. Also when you add up all the time and materials used to build your boat, and you put a realistic value on your time say $20.00 hour, you will find that even the best plywood will constitute a small fraction of the final cost. Get the good stuff (British Standard 1088, 4MM ) you’re worth it.
I have found that five planks per side for a total of ten on a canoe is not unreasonable for this technique. However when attempting to get a more rounded shape by doubling the number of planks, complexity increases as the amount of cutting, drilling, gluing and filling holes is increased significantly making the stitch and glue method less attractive or appropriate.
The boat is finished in a traditional manner with trim, gunwales, thwarts, seats shear clamps, bulkheads, deck, coaming, hatches, etc.