America's Cup sailing races hinge on seamanship, too

When Bob Miller, an Australian yacht designer, wanted to change his name, he asked a computer for a unique alternative. ''Lexcen,'' the computer spewed out.

The new Lexcen, who added the first name Ben, later tried to come up with something else unique. Through much calculation, random sampling, and tank-testing, he designed a new racing yacht. Not so unusual, except this one has flippers, or horizontal wings on the keel that sticks out from under the hull. Lateral thinking, literally.

On those wings rest the hope of Australia, which won the right this summer to challenge for the most prestigious trophy in international sailing, the America's Cup.

This week as the yacht Australia II went up against the American defender, Liberty, in a best-of-seven series of races on Rhode Island Sound off Newport, American sailors held their breath. In 24 challenges since 1851, the United States has not lost the coveted prize.

If the finned Australian challenger won, it would end sport's longest winning streak and send the silver Victorian goblet from its bolted-down perch in the Manhattan mansion of the New York Yacht Club to an obscure Australian port near Perth.

On the wharves of Newport, where the yachts dock after a day at the races, Australia II sponsor Alan Bond, a cocky bloke who speaks in Australian ''strine, '' was seen waving a gold wrench, threatening to unbolt the Cup.

But Bond, like Lexcen, recognizes that one keel does not a winner make. Both admit that the winning boat ''will make the least mistakes.''

True enough, when the races began Wednesday after a one-day delay caused by erratic winds, the Australians made a slip which cost them the opener. And as the confrontation continued, that initial contest was seen as the one that broke the aura around the magic Lexcen keel, separated fact from fiction, and brought the race back to a matter of basics, not trickery.

The slip-up for Australia II came on the fifth leg of the six-leg, triangular race course. In an above-average wind of about 18 knots, the craft was heading downwind just behind the American boat when Liberty, skippered by 1980 Cup defender Dennis Connor, unexpectedly turned. Both boats were flying spinnakers, those eye-catching colorful sails which look like balloons floating across the ocean.

In response, Australia II skipper John Bertrand quickly and sharply turned his bow toward Liberty's stern to get in a better position. The turn was too quick, and Australia II literally bowed out of the race. The strain on the rudder below was too much, and a block for a cable pulley in the steering mechanism broke, leaving the helmsman like a car driver whose steering wheel just came off in his hands. Out of control, Australia's sails filled and the yacht leaned over on its side.

As the Australian crew jumped like kangaroos to jerry-build a new rudder system, Liberty pulled ahead and won by 70 seconds.

The impish Bond later claimed, with a smile, that the repairs took 82 seconds , and thus Australia would have won by 12 seconds.

To Dennis Connor, of course, comments

like that are nothing more than rain on a skipper's face. Connor foiled the Australian boat and showed that good workmanship, seamanship, and shipshape sails make the difference in this swashbuckling sport. Like the title of his book, Connor tries to make sure that there is ''No Excuse to Lose.''

The Australians, on the other hand, played for the extreme rather than the averages. This being Bond's fourth challenge since 1974, he risked having a boat built for light to moderate winds, hoping Newport weather would cooperate.

But 12-meter yachts, which are built only for Cup racing under special rules, are really big Tinkertoys that can easily break in wind near 25 knots. To save weight and make the boat go faster, the Australians probably used light hardware. They paid for that mistake when the wind speed picked up.

The race also dispelled several myths about Australia II. Although it appears to turn faster than Liberty, Connor was able to get a good start, an important tactic in this one-on-one racing where the lead boat can ''starve'' the following boat of wind. It also was not faster heading into the wind - it barely clung to a lead on the first leg of the first race. At the same time, it was not the sluggard heading downwind that many expected it to be.

''I think the boats are pretty even out there,'' said Connor. ''The race just went our way, but it could have been something else. (Australia II) looked awfully good to us.'' Nonetheless, he says, Australia II's keel makes it a ''different'' boat than the normal 12-meter.

And being different is just what Ben Lexcen, or really Bob Miller, wanted it to be.