Riverman :

Thanks for the response and advice. There was some wishful thinking here for an easy solution and I think you're probably right and
reckon I won't fuss with this.

The thing about shortening the thwarts brings up an interesting point. A few years back Mohawk Canoes came out with an adjustable
thwart, mainly for whitewater canoes. The paddler could twist it to shorten or lengthen. I called Daryll and spoke to him about this
and he maintained that shortening the thwart decreased rocker. The canoe in question already has a flat keel-line. What I would like
to do is add a slight amount of rocker to stop the oil canning and increase maneuverability and an arched bottom to increase
secondary stability. I wondering about the memory of Royalite. If I strap ( or add a shortened thwart ) the hull amidships to arch
the bottom for several months would it just bouce back to flat or retain some arch ? My guess is that it would retain some arch for
a while but eventually flatten out. This will be the third canoe I've lost to oil canning and it'd be great to figure out a
solution.

Te Canaille

"riverman" wrote in message ...

"Te Canaille" wrote in message
news:Zpcoc.138522$f_5.46889@lakeread01...

deletions

Hi Te:

My first thought with your idea is that, since all the force will be focused
on the point where the plywood meets the royalex, when you heat it, all you
are going to do is make a very thin weak spot right along the centerline of
your hull. When OldTown (and others) form a boat from a royalex sheet, it is
completely supported by the mold, so there is no point-pressure anywhere. I
think you'd end up with a long pinch-crease, probably even with holes melted
through in places. And a weak spot precisely where you don't want it.

You would probably have to make a full-support mold, but it would have to
follow the 3-dimensional curvuture of the hull along its entire length. Not
an easy task. Maybe something like digging a shallow pit in exactly the
shape you want the hull, set the boat on it (rightside up), and dump about
20 gallons of boiling water in it? Have some cold water handy to stop the
process when it starts to deform.

Another option is to go the (ugh) Coleman route, and just put a lengthwise
brace on the floor with a center T to hold the oilcan down. My own BlueHole
oilcans like crazy (I think its an artifact of the chines getting tired), so
I just jam an ammocan under the center thwart.

Another option is to shorten the thwarts! You have some tumblehome, but if
you shorten the thwarts, it will make the hull more 'tubular', and reinforce
the bottom. I don't know how much you'd have to do this, though.

Good luck.
--riverman