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

"riverman" wrote in message
...

"Alan" wrote in message
om...

Tell us more about the damage. There are four levels of repair, so we
need
to know how badly you crashed.

1) for folds, much deleted

Hey Riverman, sure seems like you've had some experience with this. I have
a related question. My Royalite Canoe which is a 13'
footer has begun oil canning. It's got a flat bottom, hard chines, and a
bit of tumblehome. I figured the oil canning could be
stopped if I can make a shallow arch or V-bottom configuration in
cross-section. So here's what I thought to do, first mount a
section of plywood lengthwise on a strongback, then invert and center the
canoe over the plywood so that it is resting on the
interior deck along the length of the hull. Then put several straps over
the canoe and stake to the ground with enough force to
cause a curvature in cross-section. Then apply some heat ( don't think a
hair dyer would do ) to make the hull assume the desire
curvature. I'm a bit woried about how symmetrical the result will be but
if I monitor the shape and adjust straps as I go it should
not get too warped. I'd like to hear some thoughts about this.
Actually, I figure to curve the plywood just a bit for a slight amount
of rocker.

Te Canaille


Hi Te:
Hmm, I don't see an obvious easy solution to this, but what you're
envisioning doesn't look good. I once saw a royalex boat that was too close
to a campfire reach the temperature where it lost its cohesive stability.
The hull suddenly had the consistency of freshly cooked lasagna noodles, and
it was was impossible to hold it in shape with our hands while it cooled and
got rigid. We flopped it down rightside up on the ground, and to this day it
still has a completely flat bottom because of that. If it had landed on a
stick, that would have just gone right through the bottom.

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