I read a discussion where comparisons between a monohull and a cat were put to a naval architect. What I remember of it was that the rules for each are different. A catamaran can plane even tho' it has nothing like the planing suface of a powerboat, or other planing craft. I don't know why it works that way but I'm not about to discount what a NA says.
Boat designers have a rule of thumb that roughly states the theoretical hull speed of a displacement hull. HS = 1.34 x square root of the waterline length. The only way to get beyond this is to make the hull plane and most sailboats just won't do it.

: Charlie my boat just keeps taking on a new life of it's own and this is where
: I am at now, just trying out new things. I get a kick out of this. The
: boat in the picture is from the Water Tribe sailing groups in FL. Almost
: all use the Balogh batwing sail but different sizes. These setups are
: tried and proven and this is the look I am after. This type of sail plus
: my new teardrop shaped long leeboard and rudder should enable me to go up
: wind pretty good. I look for this to have adequate speed but not super
: speed like my old 15’cat, which planed on the water rather then pushing
: through it. You can have good speed with a short boat. My cat was 15 feet
: long but had a sweeping banana shaped bow that left about 13 foot of water
: line, but could through large rooster tail on windy days. The sail boards
: also have high speed with a short waterline because they plane also. What
: I am really after is a sailboat that is stable, with adequate speed, can
: sail close to the wind, can all breakdown and pack inside the kayak so I
: can paddle and have a perfect craft to explore the Northern Georgian Bay
: next fall. So this is all a means to an end, I hope and a heck of a good
: hobby.
: John