: Paul,

: To each his own.
: I already agreed you can make things as light as you want, taking
: the risk you want.

Please don't equate light weight with risk. Quite the opposite situation can happen. Consider these: An ounce of cork will float much better than an ounce of steel if both are simple, solid, cubes. If the steel is rolled into thin sheets and fabricated into a model boat it can displace quite a bit more that that cube of cork.

In defining the difference between ships and boats, the rule I heard is that a boat is what you get into when the ship sinks. Check a boating catalog for lifeboats for a sailboat or large motorboat. You'll find a few inflatables. Skin thickness on an inflatable is measure in thousandths of an inch, and the weight of one is a fraction of the mothership. But, that lightweight, flexible, craft is extremely stable and a vast improvement to the sailor's survivability.

: I'm sure we are boring the rest of the forum.

Maybe, maybe not. I won't speak for them. When they tire of a thread the readership falls off, responses stop. I've written some posts of epic length and they seem to get read--but more people read the ones with pictures.

: Please demonstrate your OSB kayak.

Hmm. sounds like a challenge. :)
At the moment I don't have an arrow like that in my quiver. But, I have some time this week so I might as well knock out a frame for one at least. Not sure when I'll be able to skin it and test it on the water. Watch for some pix in the next week or so. I found some 7/16" and 1/2" OSB at the shop, but I had dedicated that to some shelves I was making, so I'll go with thinner stuff. I have a good bit of 1/4" OSB. That should be thin enough to show the strength of the material. Any particular design you'd like to see? Any particular design features you want to see? I'm thinking of a boat about 16 to 17 feet long, able to hold a 250 pound paddler and gear.

: Real world damage tells me that I want more than the minimum.

Hmm. I'm sure there is a story there about that. Next time I show up at a convention I'll buy the first round and you can share it. Meanwhile, keep an open mind about 'minimums'. Most boats are designed to be far stronger than a minimum. Some are designed to be less than a certain minimum--and people gamble on it. Shells, for example, are thin, sacrificing stability for speed. Their light weight is a balance between durability and acceleration. On the other hand you have the old Grumman aluminum canoes. Veritable tanks! Hard to break, and when they broke they were harder to fix.

There is a serious debate in the design of kayaks about flexibility. Some people want a boat that flexes a lot and conforms with waves. Others want something stiff enough to bridge wave troughs. Both styles seem to work (or break) for different reasons. And compromises can also work--or break. Jury is still out.

: I also dislike the work and expense of glass and was interested in
: a practical alternative.

Heh, heh, heh. At one time fiberglass was touted as the "cure" for the problems of woodworking. Its ability to bridge gaps and waterproof joints at low cost and in a short time was a boon to the boat builder. It was a practical alternative to caulking seams. It still is. The emergence of new materials opens new paths to explore and is a foundation for new designs. The old ones still exist. Sometimes they get "rediscovered". Look at the resurgence of jousting, vinyl records, and slide rules. Wiat. That last one hasn't happened yet.

Seriously, though: Fiberglass can be fickle to work with, but the same can be said for varnish. Once you are proficient with a material it is not so daunting to work with it, and you can predict the cost fairly accurately. If the cost in time or cash is too high, often there are alternate methods. The Rushton canoe shown below (sorry, not mine) was designed in the late 1800s. The many long seams on Rushton canoes were sealed with a thick coat of heavy varnish. and drawn together with copper nails. The varnish isn't as durable as epoxy, but in many ways it was used for the same purposes.

Lots of ways to build boats. That is the fun of it!

PGJ