I heard about Carl Roberts planing cat but sadly never saw it. Carl's experiences with a cat's behavior when planing help visualize the problems of speed, lift and control. This may be a triangle- you can have any 2 of the 3!

It's tempting to think about dropping a planing surface under or in between the hulls when you are going fast already, but how does one get such a rig to sit back on this surface while planing at speed? Besides the force in the sails wants to blow everything sideways. Hydrofoil sailboats have the same sideforce to deal with: It looks as if vertical fins above or below the foils are necessary to deal with the wind pressure, converting it to forward motion. This is not so simple.... even when you have lifted both (light) hulls out of the water already! It makes you breathe hard and grin a lot, tho. 8^)