: Most people put on 2 or 3 layers of fibreglass tape on the seams. Could you
: get away with putting 1 layer of Carbon or Kevlar instead.

You could probably get away with putting on one layer of fiberglass tape. I can't see the reasoning behind multiple layers of tape unless someone wants to have additional resistance to dents and dings.

On strip-built canoes and kayaks the surfarce bonding strength of a sngle layer of glass cloth on the interior and the exterior are sufficient to hold the boat together. On a boat built from plywood panels a wrapping of the hull with a single layer of glass fabric (on interior and exterior) should work in the same manner.

Now obviously you have to match the strength of the glass cloth to your materials. Using 6 ounce cloth on 1/4 inch strips is obviously a much different situation than using 2 ounce cloth to join 2x6 planks. I think a lot of glass tapes are in the 6 to 9 ounce range, and should be about as strong as a single layer of 6 to 9 ounce glass fabric. (see my other note about cutting your own strips from fabric). Canoes and kayaks frequently are built with 4 ounce material, and they seem to be quite durable. Putting on three layers of a 6 to 9 ounce tape on a seam on a stitch and glue kayak or canoe would be the equivalent of using 18 to 27 ounce glass cloth -- which would seem to me to be greatly excessive. Then again, if you really needed such strength you would use two or more layers of tape that is the same width. and you would go with the widest width. The idea of using a narrow tape and then covering it with a wider one just seems odd.

Before you ask: cutting bias srips from kevlar/carbon cloth seems like it would not be a good idea. If you want the stiffening properties that come form using it in a certain orientation, then you would lose some of those properties by putting the material on at an angle.

PGJ