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