The same thing has interested me a while and I've been surprised to find no cases where two kayaks have been joined together to make a cat. One that can be dismounted, just the spars holding the kayaks together and an unstayed simple rig on one, with maybe the step on both hulls.

If joined together in a solid manner hull speeds should be no problem, but beyond? Someone must have done this somewhere...

Of course the question is: do I want a minimum of parts for real kayaking or do I want speed, and am I thus willing to have all the extras required for a real cat?

Considered as an auxiliary for expedition kayaks, ie. mostly down-wind sailing, one might get by with really simple solutions. Also, on expeditions one may occasionally need a truly stable craft in a group, eg. for injured members' transportation.

Just some thoughts on the subject.