Sailboats, Lee said, "have relatively poor visibility on ship's radar and it would be impossible for a ship to track the multitude of targets in any event. A sailboat's navigation lights can be lost against a brightly lit shoreline."
Sea conditions were discounted as a possible cause. The Coast Guard said visibility was good and ocean swells were a modest 6 to 8 feet.
The mood was somber Sunday afternoon at the Bahia Corinthian Yacht Club in Newport Beach. The club Thursday hosted the send-off party for race participants.
"The sailing community being a tight-knit community — it affects everybody," said Paul Secard, 58, who has participated in several of the races.
Secard said there are usually two people on the boat watching out for tankers or other big vessels during such races. Still, he said it's difficult to see what is around you at night.
"Nobody wants anyone injured at all, much less somebody losing their lives, for crying out loud," he said. "It's supposed to be three days of fun."
The Aegean was a Hunter 376. Mavromatis, the owner-skipper, is president and chief executive officer of Aegean Consulting Inc., which specializes in the telecommunications and aerospace industries.
The Newport-to-Ensenada race, which grew to bill itself as "the world's largest international yacht race," began in 1947 for sailboat enthusiasts fresh from the grim days of World War II. As it gained notice in the sailing community, the race began to attract both serious professionals and equally serious amateurs and hobbyists.
A boat owned by Roy E. Disney held the record for monohulls for several years. The 60-foot Stars and Stripes catamaran owned by business tycoon/adventurer Steve Fossett set a multihull record in 1998.
The race includes several classes and multiple awards and trophies. As the winners were announced Sunday afternoon in Ensenada, a gloomy moment of silence was observed for the four from the Aegean.
The Associated Press contributed to this story.