The British put on a brave front this morning, but the heart in Lionheart evidently is about to give out.

As northeast winds whipped Newport harbor under leaden skies, the Britons prepared to go to sea in their black 12-meter yacht, Lionheart. Only one more loss to the French in their semifinal American's Cup series and the English will be eliminated.

Jonty Layfield, a grinder for the Lionheart crew, was jaunty, nonetheless.

"Remember Trafalgar, remember Agincourt and Waterloo," he cheered. "That's how its going to be today."

To the tune of Funiculi, Funicola," his crewmates sang this ditty: "Bash 'em, bash 'em, up against the wall."

But when the Britons discovered the seats had been stolen overnight out of one of their support boats, a Boston Whaler, syndicate chairman Tony Boyden dismissed the problem.

"We might not need them after today, anyway," he sighed.

The last may well be first in Newport this year. The Britons were the last to bring their challenge here in June and they are likely to be the first eliminated.

Today, they were spared the agony when races for both American and foreign boats were called off in light of the roaring, rainy breeze that topped out at 35 knots.

With all the boats safely back in harbor, it left a little time to ponder one of the great questions of American's Cup competition. Twenty-three times since the yacht American captured the Cup in 1851, foreign boats have come here to try to take it away. None has succeeded.

Why?

"I think perhaps it has to do with the whole concept of the Cup," said (KEY OFF) eter (KEYWORD) Rhedin, project manager of the Swedish boat Sverige. "The America's Cup is so important here, compared to overseas.

"It's so important for the Americans to win it, and the longer they have it the more important it seems to get. That seems illogical, but it's true.

"For example, this year Dennis Conner is the difference. The difference between Courageous and Clipper (the other two U.S. boats) and the foreign challengers is none. The difference is with Dennis and Freedom.

"He has had two boats to work with; he's spent to much money; he's gone through so many people and spent so much time.

"Because the people in America know the concept of the America's Cup they will give the money for a campaign like that. At home (in Sweden), the people don't know the consequences and the need for that kind of total backing."

That's one reason. There are others.

The rules for the Cup trials favor the Americans, pure and simple.

U.S. boats race under the guiding hand of the New York Yacht Club, which mounts the defense and stages the races every three years. The NYYC's sole goal in running the U.S. trials is to select the best boat as defender.

"Our trials are hammer and tong," said Freedom skipper Conner. "When you go through three months of nonquarter racing just to win the right to defend the boats and crews are at top form."

Conner has been offshore for actual matches, under observation by the selection committee, in 36 races already this summer. By contrast, challengers Australia, Sverige, Lionheart and France have raced only 13 or 14 times.

In less than a week, two foreign boats will be eliminated. All three U.S. boats could go at it for another three or four weeks.

Jim Hardy, the Australian skipper in his third challenge effort, believes "the biggest single advantage the U.S. has is that the New York Yacht Club is an independent body and can conduct the U.S. trials however it sees fit. They can do what they have to do to see that the best boat defends."

A little later in the conversation, he one-upped himself, saying, "The most important thing is that a U.S. yacht like Clipper has a sail number of U.S. 32. Our sail number is KA5. The U.S. has built and campaigned 32 12-meters to our five and the Americans are just that much father ahead."

The foreigners have to contend with clossal logistics and expenses of moving men and machinery abroad to wage their campaigns. "When I was here in '67," Hardy said, I walked around with my mouth agape. There's hardly a boat in all of Australia as big as the cruisers you see at every dock here. Distractions like that can ruin a campaign."

The foreign challengers also have long complained about rules barring them from using the latest technological advances available to U.S. boats. After the 1977 races, the NYCC rules were changed to permit the foreigners to use any equipment that was internationally available "off the shelf," regardless of where it was manufactured.

That has drawn the competition closer. This year, the foreigners were denied access only to the latest American combination sail material that use the space-age fabric Mylar. They resent that, but acknowledge that, otherwi otherwise, their access to the most current go-fast technology is essentially the same as the Americans.

Still, they are strangers in a strange land. Their boats were built, their sails cut, their spars fabricated and their crew trained thousands of miles away, in lands where "America's Cup" is likely to mean significantly less than "Olympics" or world championships."

Under these circumstances, could the Cup ever be extracted from its niche in the New York Yacht Club?

"I think so, yes," said the suave, soft-spoken Hardy, dean of all Cup skippers at 47 years of age. "I see it like a mountain. I know how high and steep it is. It's a question of getting myself and my crew to climb it."

"Someday it will happen," Conner added. "I hope to God it isn't this year."

Meantime, there's no shortage of moths willing to fling themselves into the flames. The British are already writing off their $1.5 million-plus effort and planning their 1983 assault on the Cup.

"We've learned from this experience,"the discouraged Boyden said. "The pity would be if we couldn't go ahead and take advantage of this experience.

"There's no doubt that challenging for the Cup is an uphill fight but you know that before you come.

"We're not complaining. We always have the option of staying home, you know."