What is best: Plywood or natural wood?

You want to build a wooden boat, right? Otherwise, you wouldn't be here. But should the boat be built of plywood or of natural wood straight from the tree?

The big difference between plywood and natural wood is the direction(s) of the wood fibers. In natural wood, all fibers are pointing the same way (from the root to the crown of the tree). Plywood, on the contrary, consists of a number of thin veneers of wood that are glued together at 90-degree angles.

The biggest benefit of plywood is its dimensional stability. Where natural wood swells and shrinks (perpendicularly to the wood fibers) when the ambient moisture changes, plywood remains stable.

The "landing" of a lapstrake plank, which has been beveled to make it fit the next plank. The layers in the plywood show clearly.

Because plywood is glued together at 90-degree angles, the wood is "locked" so that it cannot shrink or swell to any noticeable degree. The dimensional stability of plywood makes it easier to work with because you do not need to factor in wood movement in your projects. 

Another appealing feature of plywood is that it comes in big, smooth sheets of even thickness. Your plywood is ready to use, and you don't need to glue up several pieces to get a wide panel. It is usually only when you need extra length (like for a boat plank) that you need to scarf two pieces together. 

Big sheets of plywood being scarfed together to get extra length.

And - being an industrial product - it is often easier to come by than natural wood, at least if you are not just interested in construction lumber from the local home center.

The first few boats I built were made of plywood. The very first one was an Optimist dinghy, that I built at boatbuilding school. The Optimist was designed by Clark Mills as a simple-to-build boat to be made out of exactly three pieces of plywood. The widespread success of these boats speaks for itself.

The second boat that I built was a 12' Guillemot glued lapstrake dinghy, designed by Iain Oughtred. Oughtred has had great success modifying traditional boat types for glued lapstrake construction. The glued lapstrake approach has a number of benefits:

A glued lapstrake boat is a monocoque structure which means that the strength of the boat lies in the planking and less (or no) framing is necessary to further strengthen the boat. This saves weight, but it also saves work, and it gives the boat a very clean interior. And being epoxy glued at all joints, the boat remains watertight, even if it has dried out completely on land. 

But for me, the glued lapstrake approach also has a number of disadvantages. One thing is that when you build a glued lapstrake boat, you spend a lot of time wearing latex gloves, handling epoxy glue. I like woodworking, but I'm not particularly fond of working with chemistry and sticky, gooey compounds.

My parents at their week-long stint of cleaning off epoxy.

But the biggest disadvantage in my view is that cleaning up cured epoxy on the inside of the boat is absolute drudgery. Most glued lapstrake boats are built upside-down over a number of molds. And while you can clean away most of the epoxy before it sets, there is still quite a bit that you cannot get to before the boat is turned over. I built the Guillemot together with my dad for my parents to use, and they wanted to give it a clear oil finish inside-out. My parents both spent a full week with heat guns and scrapers to get the interior clean enough to be oiled. The boat turned out wonderful, but cleaning out the epoxy was no fun. 

Happy boatbuilders on launch day. Everything (almost) forgotten.

Since then, I have only built boats out of natural wood. This is partly because of "Scraping-Gate" but also because I now have access to a big bandsaw and a thickness planer so that I can mill my own lumber. 

But mainly it is because I enjoy working with natural wood more than working with plywood. I think that natural wood feels better and looks better. It smells better. There is no glue and no crumbly shavings. You don't need to worry about sanding or planing through the face veneers. It is more woodworking and less chemistry.

- Mikkel Pagh