With a sleek, pointed nose, and top speed of more than 50 mph, a new jet-powered ferry on the Gulf of Maine inspired awe and fear on its test run.

"It's big, it's mean, and it looks like it could go underwater any time," Shawn Duncan of Bar Harbor said Wednesday as passengers played slot machines, socialized at bars or watched from the rear rail on a test run of The Cat, North America's fastest car ferry."I wonder how she's going to act in a heavy breeze?" wondered Keith Raymond of Digby, Nova Scotia, a veteran of crossings from Bar Harbor to Canada on the conventional ferry that is being replaced by The Cat.

The $44 million vessel, with 667 passengers on board, was more than two-thirds full when it left on its maiden trip to Yarmouth, Nova Scotia, this morning. It arrived in Bar Harbor a day earlier, attracting scores of camera-toting spectators who stood along the shore to get a glimpse.

Even with a full load of 240 cars, four buses and 900 people, the Australian-built Cat can do 50 mph. With a lighter load, it can get up to 58 mph. It can also come to a complete stop within seconds, a fraction of the time it takes for a conventionally powered ship to stop.

That should allay the fears that lobster boats and whales will be run down by the 500-ton vessel, said Don Cormier, general manager of Bay Ferries Ltd.

The Cat also has only 12 feet of ship below the surface, compared with conventional ships, which can have 30 feet or more of their structure underwater.

The Cat can complete the run from Bar Harbor to Nova Scotia in 2 1/2 hours, compared to six hours for the ferry it replaced.

Its jets thrust as much water in a second as it would take to fill several Olympic-size swimming pools.