The near-sinking of Young America in America's Cup challenger trials 2 1/2 months ago was caused by a faulty repair to a side deck, the chief engineer of the design team said today.

The collapse in strong winds and big seas Nov. 9 of the New York Yacht Club's top-rated entry provided spectacular photos of the boat cracking up and led to Young America's early elimination. The team switched to a second boat but was unable to stay competitive, though team officials insist they had two of the fastest boats of 11 challenging teams.

Russell Bowler, chief engineer at Bruce Farr Associates, the Annapolis-based company that designed the boats, said the repair to the side deck of USA 53 was made by unnamed team members "at a time when neither the builder nor those involved with the composite design team were present." He said the patch was "inadequate to carry the compressive loads."

Bowler said a 10- by 15-inch section of outer deck skin near the front of the cockpit was replaced because its bond to inner core material looked to be failing. America's Cup class boats have outer and inner skins of ultralight carbon fiber bonded to a honeycomb inner core.

He said Farr & Associates was speaking out because "we were the recipient of quite a bit of criticism on this issue," while it is under investigation for insurance claims and by Young America officials. Bowler said the company was "frustrated with all this being thrown at our feet" and felt "something needed to be done, so we went ahead and did it."

He said the bonding failure was spotted about a week before the mishap and repairs may have been rushed due to budget constraints. "The program suffered from budget cutbacks," said Bowler, adding that some team members worked 18 hours a day for weeks. "People weren't operating at their best."

He said Young America had earlier problems with bonding skin to core and had to make some repairs after the boats were launched in September. "Looking back, there were hints from this work that there was more to come, and sitting here with the benefit of hindsight it's easy to say somebody should have heeded the warnings and done a little more to investigate."

He likened the ultralight Cup boats to Formula One race cars, but conceded they should have been strong enough to withstand stormy days on Hauraki Gulf. Bowler said the failure occurred when Young America hit three waves that nearly stopped the boat with a shock so intense, hard drives on all the onboard computers quit. He likened it to a Mack truck hitting a wall.

Bowler said he was stunned by the incident because side decks of Young America were made extra-thick with 5 millimeters of carbon fiber on either side of the core for strength--five times the thickness of other, non-stressed sections.

"Contrary to a lot of speculation," he said, "the design was not marginal or light in this area but in fact had adequate material to resist the given loading."

But Bowler conceded the yard team that worked on the boat was probably not warned of the need for care in repairs. "There should have been a system of reporting," he said, "to make clear to the team these pieces need to be treated as you would a mast or any other compression-loaded piece."

He said the near-sinking left a scar on the entire team. "The team includes some clever, talented people who have been thoroughly humbled by the events of November and December."