Michael Fay doesn't like his chances if he has to sail his 123-foot-long monohull against San Diego's catamaran in the America's Cup regatta.

"I think the facts of life are that catamarans beat monohulls," Fay said Tuesday before his New Zealand challenger yacht made its first U.S. practice run.Fay, a millionaire New Zealand banker who forced the San Diego Yacht Club into an early defense of the Cup, has filed a court challenge contesting use of the multihull in the September race.

He declined to say whether he would race the 60-foot catamaran should he lose the court case, now before the state Supreme Court of New York. The court has jurisdiction over Cup disputes.

"We didn't put a team and a boat together and come here not to sail for the America's Cup," he said. "On the other hand, I can't think of a more unfortunate precedent to set for the Cup than to see a mutihull and a monohull race."

Fay claims catamarans are illegal under the Deed of Gift, a document outlining the basic rules of America's Cup competition. He said the defender must meet him in a similar boat.

The San Diego Yacht Club and its defense manager, Sail America, claim they can use any boat designed within certain length restrictions in the deed, which makes no mention of the number of hulls.

A catamaran has never been used in the 137-year history of the America's Cup.