Strip-built, or "strip-plank epoxy", is a method of

boat building Boat building is the design and construction of boats and their systems. This includes at a minimum a hull (watercraft), hull, with propulsion, mechanical, navigation, safety and other systems as a craft requires. Construction materials and met ...

. Also known as cold molding, the strip-built method is commonly used for canoes and kayaks, but also suitable for larger

boat A boat is a watercraft of a large range of types and sizes, but generally smaller than a ship, which is distinguished by its larger size, shape, cargo or passenger capacity, or its ability to carry boats. Small boats are typically found on i ...

s. The process involves securing narrow, flexible strips of wood edge-to-edge around temporary formers. The temporary formers are usually created via a process called "

lofting Lofting is a drafting technique to generate curved lines. It is used in plans for streamlined objects such as aircraft and boats. The lines may be drawn on wood and the wood then cut for advanced woodworking. The technique can be as simple as bend ...

" whereby a set of tables is used to generate the shapes of the formers. The strips are glued edge-to-edge with epoxy. It is effectively a modern form of carvel which needs no caulking and which is both stiffer and more watertight. In a small boat, there will be just one layer of strip-planking, but larger vessels may have two or three layers which, (being a pre-shaped

marine ply Plywood is a material manufactured from thin layers or "plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. It is an engineered wood from the family of manufactured ...

), forms a light, strong, and torsionally stiff monococque. Kayak wood strip-built

A modern development of this construction procedure is "radius chine plywood", a method devised by yacht designer

Dudley Dix Dudley Dix is a yacht designer, of South African origin, now based in Virginia Beach, US. He graduated from the Westlawn School of Yacht Design. He is notable for having developed the "radius chine plywood" method as a basis for boat constructi ...

which gives a fair hull that is both light and stiff. Dix uses this boat-building method for most of his designs.

Smaller boats

These are the most popular among boatbuilders. Some professional builders also offer both kits and finished boats. The canoes are constructed by gluing together 1/4" x 3/4" strips of wood over a building jig consisting of station molds that define the shape of the hull. The forms are cut as a series of cross-sections of the final design and set up along a "strongback" or another solid base. The strips are shaped with bead and cove router bits. Stripping begins at the sheer line and finishes with "the football", a pattern of planks at the bottom of the boat. The strips are edge-glued to each other, being held in place with nails, staples, or simply clamped to the forms. Once the strips are glued together, and the staples/nails removed, the inside and outside are sanded fair. Fiberglass and epoxy are applied to the canoe inside and out. The fiberglass covering is transparent, waterproof, and allowing the wood strips to be seen. The strips are usually cedar but can be any type of wood. Contrasting woods are sometimes used as accent strips. The last steps in construction is to install the seats, thwarts, and gunwales. Finally, a coat of marine-grade polyurethane is applied to protect the wood and epoxy from ultraviolet light. In the 1950s, this process for building canoes and kayaks was adapted from ship/boat building techniques, and refined by a group of Minnesota canoe racers, primarily: Eugene Jensen, Irwin C.(Buzzy) Peterson, and Karl Ketter.

Larger boats

Strip-plank epoxy planking may be found on large yachts such as the Brady 45 catamaran, a plans-built Australian design with Indonesian cedar planking. For a large catamaran, this construction method produces a tough hull with an inherent buoyancy. Once the strip-plank monocoque is completed, it is covered inside and out with glass fiber matting and epoxy resin. Working primarily with wood is much more pleasant for the builder than building exclusively with

fiberglass Fiberglass ( American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cl ...

, which can cause irritation and respiratory problems. Also, for a one-off constructor, it makes little sense to build a female mold; it is simpler and cheaper to manufacture a wooden jig that may be discarded afterward.

References

External links

Canoecraft: an illustrated guide to woodstrip constructionBrady 45 videoBrady catamarans homepage
Shipbuilding Woodworking {{ship-type-stub