(FORTUNE Magazine) – Tasmanian boat builder Robert Clifford guides his new vessel, a 300-foot-long catamaran called Avemar, down Hobart Harbor on her first sea trial. Built for carrying cars and trucks, Avemar (Spanish for "sea bird") is made of aluminum and weighs about 670 tons empty. Clifford gooses the throttles, and in the engine rooms gigantic Caterpillar diesels crank up the four pumps that propel the ship, squidlike, by sucking in seawater and forcing it aft. Soon the pumps are churning a volume of water equivalent to the contents of an Olympic swimming pool every 16 seconds (or, as Clifford likes to say, "66,000 glasses of beer a second"). Avemar skims across the harbor at 45 knots, or 52 mph--fast for any ship, almost unbelievable for a ferry.

Hobart, Australia's southernmost port city, has seen strange vessels of many kinds in its day, from prison ships filled with exiled Englishmen to steamers carrying explorers bound for Antarctica's unknown. But until 1990 neither Hobart nor any other harbor had seen the likes of Avemar, latest of a new breed of ferry pioneered by Clifford, chairman of the Incat Australia shipyard. The boats, called wavepiercers, combine three attributes: light weight, high performance, and big payloads. One might add a fourth: uncanny, almost feline, looks.

The boats' appearance, like their performance, derives from the innovative design of their narrow "wavepiercing" hulls, which move through the water like racing shells. Between the hulls is a third, a quasi-hull, like a big throat beneath the bow, which gives additional buoyancy in rough seas. The superstructure is streamlined to gain every knot from the New Age propulsion. As in an airplane, weight is pared to a minimum. Ferry operators whose vanity permits it forgo paint, which can add as much as a ton.

Loaded with 900 passengers and crew, and a lucrative mix of cars, buses, and freight trucks, one of the boats can carry almost her own weight. That has made wavepiercers the leading choice among ferry operators looking for speedy ships to replace outmoded plodders in the competition heating up on long runs. Other shipbuilders are getting into the act as well, designing fast catamarans, or "cats," of their own.

Clifford, a Hobart native, has been building boats since childhood. Once he made a wooden dinghy for a school project that was so good his teachers thought his parents had helped, and they flunked him. "Actually, my father did help," Clifford says. "He took my mother out so I could remove a window to get the boat out of my room." As a young man, when he wanted to fish the turbulent latitudes called the Roaring Forties, he built a wooden fishing boat. Soon he started a small ferry service on the Derwent River, which divides Hobart. The line carried commuters who wished to avoid a congested bridge.

Clifford's first lucky break came in 1975 when a ship rammed into the bridge, suddenly increasing demand for ferry service. In the three years it took to fix the bridge, Clifford added new boats to his fleet. One, a small hovercraft, was fast, but it was a maintenance nightmare, and Clifford started thinking about ways to improve on it. "Our cats actually began by [our] analyzing it," he says. The hovercraft, he realized, was "really a narrow catamaran with skirts to contain the air blast." Clifford's idea was to "throw out the skirts and fans and design two efficient hulls."

In 1977 he formed a company called International Catamaran (later shortened to Incat) and took on a like-minded naval architect as a partner. Their first wavepiercer was Little Devil, a jaunty 26-foot outboard in which Clifford took passengers zipping across the harbor.

As Clifford experimented with further prototypes, he ran into a problem with propellers: At speeds over 30 knots, bubbles streamed from the blades so that they no longer bit the water efficiently. He found an alternative in big water jets, some adapted from sewer pumps, that were being manufactured for ship propulsion. "The water jets made it all possible," he says.

He built a new yard on the Derwent and began looking for commercial customers for his fast cats. Initially, orders were slow. But then he got his second lucky break: In the late 1980s the Chunnel under the English channel was burrowing to completion, opening a new market for transport.

Sea Containers, a British shipping company, had been operating hovercraft ferries on routes between England and France. Fearing the competitive challenge of the Chunnel, the company began looking for something less complex and less costly to operate. "Our opportunity came when we read of their need for a faster, better boat," says Clifford. He raced to England with his plans, and Sea Containers was interested.

Clifford built a cat for Sea Containers and launched her in 1990. Called Hoverspeed Great Britain, she was 240 feet long, 80 feet wide, able to carry 600 people and 90 cars, and capable of speeds over 40 knots. On the Atlantic leg of her delivery voyage, she wrested the Hales Trophy for fastest crossing from the liner United States, which had held it since 1952. (Last summer two new wavepiercers bested Hoverspeed; the fastest averaged 41 knots.)

Hoverspeed's performance wowed ferry operators around the world, and they began replacing conventional vessels with wavepiercers on high-volume runs. One jets between Naples and Palermo in less than five hours. Another whips across the Plata River between Buenos Aires and Montevideo in two hours and 45 minutes; a conventional ferry takes about ten hours to make the trip.

Now the market Clifford created includes more than 90 boats. Twenty-eight are wavepiercers; competitors built the rest. Australia's navy acquired a wavepiercer to move troops and supplies rapidly to East Timor. (The navies of the U.S. and other countries are said to be interested too.)

Incat has grown to a company with annual revenue of more than $200 million. Clifford, who with his family owns 85% of the business, travels the globe drumming up orders for the four or five boats the yard builds each year. On the drawing board is his biggest yet: a 390-foot wavepiercer that will carry 1,200 tons at 60 knots--"something no other big ship has done," Clifford says. Clifford thinks it not impossible that one day he will build a ferry that can travel at 100 knots.