Beautiful, Lightweight and Affordable
Stitch and Glue Canoes Under Construction
What Is Stitch and Glue?
The term comes from the process of joining planks lengthwise edge to edge using wire ties called stitches. Planks are cut from thin marine plywood and the stitches hold them together temporarily for gluing and glassing.
Plank patterns are designed in 3 dimensions on the PC to meet the intended use of the craft. These "expanded" patterns are then “flattened” to create plank patterns for hull. Small scale models can be made to help the customer visualize the final shape prior to final construction.
Once planks are wired together, the seams are filled with a thickened epoxy slurry. Once cured, the wires are removed, all remaining seams and holes are filled and the hull is carefully sanded in preparation of fiber glassing and final finishing.
After the glass is applied, the boat is finished in a traditional manner with trim, gunwales, thwarts, seats shear clamps, bulkheads, deck, coaming, hatches, etc. It is a well established boat building method for the do it yourself builder and is also used by some commercial concerns to create significantly larger craft. The skin of the craft becomes a load bearing structure similar in construction of an airplane’s monocoque fuselage. Monocoque construction means the outer skin carries all or a major part of the stresses. This results in a lighter, stiffer boat. It is an ideal technique for other small wood watercraft including yacht tenders, prams, pulling boats, sailing dinghies, etc.
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. Working six or seven planks per side in an attempt to get sweeter lines, one might consider glued lap construction exchanging all the drilling and wiring for building a form and clamping. Folks most interested in a round or smooth bottom hull, the preferred method is strip building.
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.
In thinner dimensions (3MM and 4MM), quality marine plywood is much stronger than conventional planking of the same thickness. This is due to the cross wise lamination of veneers and thickness can be proportionally reduced. Plywood thickness has its limitations with respect to the minimum bending radius. It is feasible to cut the individual planks of a lapstrake hull out of plywood sheets.
BS1088 is of the highest quality marine ply with a defect free core and both faces of solid A surface. A majority of this marine plywood is made from the Okoume (Acuomea Kleinea) tree harvested in the tropical forests of the Congo Basin, primarily in the African state of Gabon. Virtually all this marine plywood is manufactured Greece, France, Israel and Asia. There is also a BS6566 standard which is less species specific and is more permissive so the surface may show skin defects on one or both faces. I have no experience with this grade or with any grade of US marine plywood. Without question in a small, small boat, where the materials call for 2 or 3 sheets for hull, I'd plan on okoume.
Always check the ply when ordering to make sure you get what you ordered. Just because it is labeled BS 1088 does not guarantee it is in fact 1088. Douglas Fir based marine ply is better suited to larger craft than canoes or kayaks. Boats like those designed by Philip Bolger or Jim Michalak.
Fine Wood Watercraft has over 30 designs for canoes and a comparable number of kayaks for stitch and glue construction. Plans are quickly and easily customized to suit your unique needs. I don't have the time to get descriptions for each design placed on the web site. If you call and we talk, I can email you a PDF overview of the design you seek. From there modifications can be easily made and the final agreed upon plans emailed using a PDF or printed version sent via snail mail upon receipt of payment.
Do you have suggestions or comments?
