Why foam instead of plywood?

Ray Kendrick offers his scarab22 in foam/fiberglass or plywood/fiberglass. In both versions, the glass is an essential structural component. Here is a table of the pro's and con's of both methods (my opinion...)



light (lightest method) heavier (still light, but there is a weight penalty. This will impact speed and load carrying capacity).
expensive (the foam itself is $$$ and you need more glass and epoxy). My cost is about 6$ per square feet. economical (the wood can be obtained at good prices and you need less sticky and itchy stuff). Cheap plywood will still be 2$ per sq. ft. Add glass and epoxy and you get awfully close to foam price... Maybe not that econo after all...
ugly (usually, the color is and it is boring) nice (beautifull grain showing through the epoxy and it smells good!)
water proof (I mean, it does not rot or swell or shrink or split and you can wash sanding dust with water, dry it and continue working) not water proof (You have to keep water from touching it constantly. Water is not friendly to wood. :-(
will tolerate neglect (the material is not biodegradable and will last and last and last...) will NOT tolerate neglect (let bare wood exposed for a season and you're in trouble! It will rot or swell or split or all of the above.)
high resale value (look at Corsair trimarans...) lower resale value (people are affraid of wooden boats in general)

If it is important for you to enjoy the actual construction of the boat, I think plywood is the best choice. It is very pleasant to work with and has a nice feel under your hand. But in the long run you will spend some time maintaining to boat and will be worried everytime the wood gets wet because of damage.

If you want to maximize your time on the water and do some racing, foam is the way to go. You wont care if there is a leak through the deck or if the bottom is scratched on the beach. You can delay repairs for very long and go sailing instead. On the other hand you will have to paint the interior to make it look decent... No varnished mahogany in there!

For me, the fact that the material is totally waterproof and can tolerate neglect are the deciding factors. I love wood and woodenboats, but I love sailing more!

One option is to have some wood where it makes more sense and where it can be apreciated more. One example that comes to mind is the tiller... I think I will make mine with a combination of brazilian rosewood, ebony and spruce, just like a musical instrument !


Here is the tiller on my old woodenboat (laminated white pine with epoxy and Cetol varnished):