"Yanie" wrote in message
m...
Someone recently mentioned to me the idea of a long river trip, and we
were debating different types of craft that we could use. Somehow I
became hooked on the idea of joining two canoes into a catamaran, as
in the linked diagram. The spars and crossbeams would all detach when
there is no wind, and be readily assembled when the wind picks up
again. I've seen plenty of articles and posts about different rigs for
a single canoe, but none for joining two.

I'd think the benefits would include greater stability and the ability
to carry a bigger rig.

I assume someone has thought of this before, so what are the
disadvantages? Is the idea feasible?

http://www.beowolf.org.uk/misc/sailing_canoe.png

Oh, its absolutely feasible. I once crossed Chipenetticook lake in Maine
(about 8 miles, IIRC) by lashing two canoes together, raising an H-shaped
mast with a huge tarp tied on to it, and sailing across in record speed.
Each canoe had a bow and stern paddler: the bow paddlers held the uprights,
one stern paddler was me, on the rudder, and the other held two ropes
connected to the top of the masts, like reins. He 'trimmed' the sail by
pulling in the reins, one side or the other, or both (which had to be
wrapped around gunnels). We quickly discovered that the canoes had to be far
apart to keep the bow wave from coming up between them, and for stability
when tacking.

One problem with your setup in the .png is that there needs to be a
diagonal brace between the canoes: they shift around a lot and you need to
firm up the rig. Also, there is a lot of trimming of the mast that will have
to take place, and in a 'fixed' rig like yours you may be underestimating
the force on the stays, sheets and blocks. Our own rig was difficult to hold
on to with the stiff breeze we had; a strong gale would have necessitated
taking it down quickly, and I don't think your fixed rig could be derigged
fast enough. Also, the bow of the canoes tends to sink down, and in a stiff
breeze the bow wave comes aboard. We could lean or slide our mast forward or
back to dump air or balance the boats, but in your rig, I don't think you
can trim it easily enough.

All that being said, try it out. I think you have FAR too much sail in your
drawing; maybe some sailors here can tell you the formula for hull volume
vs. sail area.

--riverman