The most common greeting around Newport, Rhode Island, as the America's Cup summer winds down is, "G'day, mate," which is how Australians say howdy.

And Australians are everywhere. "It's simple," said newspaperman Piers Akerman, who flew in from Sydney this week for no other reason than that he feels he must be around if his nation is to enjoy its moment of international sailing triumph next week. "You get on a plane, have a couple of drinks, and 20 hours later, there you are."

Perhaps the only way to arrive quicker would be aboard the second most interesting Australian boat in town, ranking behind only secret-keeled Australia II, the 12- meter challenging for the Cup.

That would be the Australian 18, pronounced "Strine Ayedeen" in the native tongue, which its fans claim is the fastest monohull sailboat in the world. Boatman will not argue that after screaming around fog-shrouded waters aboard Tia Maria, the world champion Ayedeen, with skipper Peter Sorenson and crewmate Andrew Buckland.

Normally there's nothing special about screaming around waters in a fast sailboat -- except when the wind is only blowing about six knots and the boat is skimming along at about twice that.

"It doesn't seem like much breeze here," said Buckland as we rigged the boat on the foggy beach, "but once you're out there, you'll think it's a bloody hurricane."

"She's not a standard recreational sailing boat," added Sorenson as Boatman climbed into a wetsuit. "We don't pack a picnic lunch."

Under spinnaker, the Ayedeen carries an astonishing 1,500 square feet of sail, which is a good bit more than a race-ready J-30 might carry. The J-30 sleeps five and has a galley and a nice keel and a place to go to the potty.

The Ayedeen weighs 140 pounds.

She's 18 feet long. She's also 18 feet wide. "It's a square boat," laughed Buckland, who with Sorenson and a third crewman sailed Tia Maria to the world championship in New Zealand last month. They are in Newport for the North American title races this week.

The hull alone, of course, is not square. It's a bowl-shaped affair, made of carbon fiber slapped over an air-light core. The bowl is 18 feet long and eight feet across. What makes her 18 feet wide are the two aluminum ladders that extend off each side. Its crew of three (that would include your basic Boatman) is supposed to scurry out the ladders and use its weight to keep the whole affair from capsizing.

"If you're inside the boat, it means something's gone wrong," said Sorenson.

And we were off, sailing straight out into a custardy fog that immediately enshrouded the vanishing shore and gave us 100 feet visibility at best.

Sorenson called for the bag, which is what Aussies call the spinnaker, and Boatman found himself setting and trimming it and then ordered out on the rails to keep the streaking Ayedeen on its feet.

He wishes he could say it was a great, exhilarating pleasure, but in truth Boatman found it a great, confusing scramble because he could not give himself to trust the tiny wire halyard from which he hung, suspended over fast-rushing green water, while a boat went dashing along in the chop five feet away. His boat.

"Trim the bag," hollered Buckland, and Boatman watched in horror as the leading edge of the immense white spinnaker began to roll over on itself. He hauled away "Bloody great sod, trim it!" shouted Buckland and at last the chute filled and the little boat took off like a 727 leaving the ground. Wow.

We sailed until we nearly clanged into a rocky headland, turned around in a crash and clatter of sharp gear and tense lines and sailed upwind until another headland loomed ominously.

Back and forth we tacked across the gentle chop, lost in the mist, the boat streaking like a jaguar and its busy crew scrambling like monkeys 18 feet across an eight-foot- wide boat each time she changed course until at last came the mournful "hoot-hoot- hoot" of friends on shore calling us back with the car horn.

Back on the beach, Buckland explained that the Ayedeens evolved from Sydney harbor boats that delivered goods back in the days of sail a hundred years ago. When motorboats came along, a racing mentality overtook the outmoded little yachts.

It's a lot like the history of log canoes on the Chesapeake, and the boats are similar in concept, only nobody has bothered to update the log canoe to carbon-fiber, high-tech status.

Boatman, nursing his bruises and puffing with the exertion of his little sail, thought to himself how nice it would be if nobody ever did.

He waved to Sorenson and gave him a hearty, "G'day, mate."