Originally Posted by RHP
That said, I have seen catamarans with single unstayed mains'l masts, one on each hull.
The first pic looks nice, sporty fast. The hulls smell the seventies...Imagine now the inertia of the weight of such twin rig balancing front to back, and side to side. Because there are not miracles in engineering. Two mast are always heavier than one and you'll need 2 mainsails and all the hardware.
And the tracks which permit the control of such high aspect ratio mainsail are cruelly missing at least on one side.
Pretty expensive and none of these rigs has showed so great qualities that they became the mainstream of efficiency...
All has been experimented many times since 50 years with the same results. And the result of 50 years of work by a lot of able people on multis is the sloop rig you see now from the beach cata to the maxi trimaran.
The second pic, and the animation show a very mainstream cat with the complication of 2 masts, double hardware, and no tracks to control the sails. Plus 2 sails to tune and twice the work for reefing doing the monkey very close to the water.
I leave you to imagine the stresses induced in the mast by the boom and the probably hydraulic controls. I would prefer a a single mast, a beefy track on the rear beam, with double chariot on rollers so you can open and close the sail in seconds, just one sheet on a 3 speed winch to free in case of problem, a good automatic solent jib on track so you can work it as needed to tack in seconds in the middle of a busy harbor entry...