This is the Itzacat designed by Alex Cirrigottis and Greg McKee in 1980. We...
This is the Itzacat designed by Alex Cirrigottis and Greg McKee in 1980. We received an Australian design award. Alex had made the very first production prototype and Greg revised it and reshaped the planing hull with sharp chines to reduce drag and increase lift. We later made a design registered 17ft step-hull version in 1982 with hulls based on seaplane floats. The sail in this film is very poorly cut and not working well yet the boat can easily keep pace with a skiboat.
Normally in even in this quite light wind it would sail considerably faster with a well cut sail and the leeward hull would plane higher out of the water, bouncing over the chop
We did not have time to recut the sail before we had to return the borrowed camera to the ABC studios.
This film was hurriedly made at Palmbeach in Pittwater on Sydney Australia's northern beaches, and publically shown at the 1983 longbeach boat show in California.
Few potential customers could understand the planing concept and some thought there was something fishy about it appearing to travel so fast, despite the obvious spray from it planing and the spray from the skiboat.
Unlike a deep V displacement hull cat, It could turn and tack as fast as a skiff because the flat hulls gave no resistance to pivoting.
The itzacat sold well to engineers and science teachers who understood why it worked so effectively.
The hulls are set at an angle so that when one hull is flying, the other hull is flat on the water.
If it heeled too far the rear crossbeam hump would send up a roostertail so it's most efficient mode was sailing with the windward hull just an inch or two off the water.
The itzacat could plane in about 7knots of wind and could easily outpace a hobie 16 or hobie 18 in about 15knot winds. It could tack as fast as a laser dingy and was fun to sail in ocean swells, easily able to catch swells and sail at crazy speeds. Being low to the water it was very wet to sail.
We contemplated a raised trampoline as per hobie cat but put development funds into a larger 17ft step hull version.
View www.mckeewildthings**** for images of my biplane rigged stephull prototypes from 1979 and step hull sailboards.
When I first met Alex by accident at Narrabeen lakes in 1979, he had an earlier version of the Itzacat with round chine hulls and I had an RC model of a biplane rigged cat which sailed completely foil-borne on surface piecing foils and had a solid wing rig on each hull adapted from one of my symmetrical wing section aerobatic sailplanes
Our 17ft stephull cat was astonishingly fast but unfortunately was confiscated by pittwater council for being moored illegally at Bayview and was never returned.