: I like to fool around with new ideas, and I did some experimenting
: recently to see if Kurt Hughes cylinder molding technique, used
: on several of his trimaran designs, could be adapted to making a
: monohull such as a canoe. It wasn't a total success but I found
: it interesting. Perhaps with a bit more development the bugs
: could be overcome.

: In essence the cylinder molding creates a ply hull by forming a
: multilayer ply sandwich around a cylindrical half-hull form. The
: mold section has the midships profile along its entire length
: and is straight. Two ply sandwiches are made in this fashion
: then trimmed around their edges, forced together along the
: centerline and taped to form a full hull. It only works for very
: narrow hulls, trimaran amas for example, as ply can only be
: tortured so far.

: I tried to adapt it for building a stripper canoe. My method was to
: lay the strips up on the cylindrical form dry, then bend the
: entire thing to create the curve of the sheer in the plan view.
: A coat of thin epoxy would then penetrate between the strips to
: hold the strips together so the half-hull could be removed from
: the mold. I had hoped I could make 2 half-hulls very quickly and
: fasten them together. The dry strips slide against each other
: when bent, and the bending forces are much less than with the
: glued ply sandwich. The hull halves would have held their shape
: and fitted together without much forcing.

: So much for the theory. It actually got quite close to success, but
: although the strips were happy to bend across either their width
: or their thickness, they did not like being bent both ways at
: the same time, so a few strips kept trying to climb over each
: other. I could have used staples to tame them, but I had hope to
: avoid that. Probably narrower strips would have reduced or
: solved the problem.

: Anyone interested, even in a failed experiment, can see more at my
: blog http://theancientkayaker.weebly.com/cylinder-molding.html

Hi ak,
Constant camber molding would be easier than cylinder, the difference is that the curve you put on the strips and mold is already there. It can be made shorter than the cylinder mold and sections of hull made to be fitted together as a hull. There's also less 'torturing' of the hull panels to mate them along the keel line and stems.

Mike Savage
South West Cork