: Wonder what these guys use for backup floatation?

If you check www.google.com,one of the currently popular internet search engines, and insert the search phrase "concrete canoe" you'll get over 30,000 hits.

There are a lot of such boats out there. (maybe because it is so hard to break them up and throw them out) With concrete boats there seams to be a blending of the lines between canoe and kayak, with many concrete canoes being partially decked. This increases the strength of the hull (allowing thinner and lighter concrete sidewalls) and also provides the necessary trapped air space which keeps these things from sinking when filled with water.

They are cheap and fast to build -- no ripping strips, no sanding, an no fiberglasing needed. Paint is optional. If you have the strongback and building forms left over after building a stripper, set it back up and cover the thing with 4 to 10 layers of chickenwire. You may want to set the forms slightly farther apart to give added length and volume to the boat. This will increase the displacement, and partially offset the weight of the materials used in the hull. The added length may help with speed.

Use some bare metal wire as twist ties to gather the loose layers of chicken wire together into a rather tight quilt, about 3/16th of an inch thick, or thicker, with the ties rather close together. Then mix up a batch of concrete and plaster the thing, forcing the concrete well into the mesh of wires. If you have acces to specialty high-strength concretes, try them. If not, you can try common sandmix. 150 to 200 pounds of concrete should do, and at retail prices that is probaly well under $15, so experimentation is rather cheap. Reach inside to smooth up the mess. After the concrete has hardened, soak it or a week, or sink it in your nearby lake, so that it stays moist while the concrete evelops some strength. Then take it out and paddle merrily -- or if that doesn't work, swim the few feet back to shore and save your pictures of the launching

I don't recommend concrete paddles.

PGJ