America's Cup racing was postponed for lack of wind today as a high-pressure system settled over the Hauraki Gulf.

Competitors wallowed around on a gentle swell for two hours, waiting for a sea breeze to fill, before the race committee sent them home. The delay gave top-rated Italian entry Prada one more day to recover from a stunning dismasting on Wednesday, while the crew of U.S. entry Stars & Stripes continued to work to repair damage to their transom from a collision Wednesday with the French boat Le Defi Francais.

Prada was back out on the race course with a replacement mast only hours after its 100-foot carbon fiber spar snapped in half in the early stages of a heralded matchup against regatta co-favorite AmericaOne.

The breakdown on the first leg of their race Wednesday forced Prada to retire, handing AmericaOne an easy win and plummeting the top-rated Italian entry to a fourth-place tie in six-boat semifinals with a 1-2 record. The damage was severe, but Prada, with the biggest budget and best-equipped compound in the challenger fleet, had its sleek silver boat up and running again just two hours after arriving at the dock under tow.

In an amazing display of efficiency, Prada's shore crew stepped a replacement mast and had the boat under tow and headed to sea to make sure everything worked long before the sun sank Wednesday. Prada was back out early today for more testing before its scheduled race against the winless Le Defi Francais in the fourth day of semifinals.

But the weather intervened and race day four of the 10-day semifinals was pushed back to Friday.

Time is beginning to run short for the Italians, who lost only three races in 2 1/2 months of preliminaries but have lost two of three in the semifinals. Six semifinalists are vying over 10 days for two challenger finalist spots.

AmericaOne, Paul Cayard's San Francisco entry, was co-favorite with Prada going into the semis and Wednesday's match was expected to be tight and telling. So it was, but too short. The five-minute pre-start was spectacular as Cayard miraculously dodged out of a trap set by Prada skipper Francesco deAngelis, barely avoided a collision and scooted off the line with a 12-second lead.

But speedy Prada roared up from astern and had just about caught up when, with a rending crack, the 110-foot carbon fiber mast snapped in the middle..

The lopsided win left AmericaOne at 2-1, tied for second place in the standings with Nippon. Both trail the surprise fleet leader, Dennis Conner's Stars & Stripes, which recorded its third straight win in a wild race against Le Defi Francais that left Stars & Stripes damaged and in need of a day off to make repairs.

The boats collided as they raced into the second turning mark under straining spinnakers in 14 knots of wind. The French boat had caught up from behind and was bidding to overtake when skipper Bertrand Pace miscalculated a course correction and smashed his bow into the transom of Stars & Stripes.

On-water umpires flagged Pace for failing to avoid a collision. The mistake ensured an easy win for Stars & Stripes but damage proved serious. Crewmen slapped duct tape over the three-foot long crack but not quickly enough to keep seawater from surging in.

After crossing the finish more than three minutes ahead of Le Defi, Stars & Stripes requested and was granted 24 hours to dry and patch the wound. Today, Stars & Stripes requested an additional 24 hours. The decision on whether to grant additional time was to be made before racing resumes on Friday.