LOS ANGELES — Surfing icon Laird Hamilton recently started a clothing line distributed by the Steve & Barry's chain.

Nissan Motor Co. promotes "surf safaris," and chemical maker Saudi Basic Industries Corp. runs ads featuring surfers chasing the perfect wave.

They are among the companies trying to capitalize on surfing's youthful, free-spending market.

They want to ride the sport's commercial wave by selling everything from clothing and sandals to cars and credit cards.

"Everybody wants to be part of this," said Ronald Enriquez, general manager of Jack's Surf Shop in Huntington Beach, Calif., which bills itself as Surf City. "Everybody's looking for the fountain of youth."

Last month, Nike Inc. executives visited Enriquez's store to find out what customers considered cool. Meanwhile, J. Crew Group Inc. and Abercrombie & Fitch Co. are pushing casual clothing, hoping to make inroads against Quiksilver Inc., the leading maker of surf-related clothes, sandals and gear.

The image of surfers as pot-smoking slackers has changed dramatically since 1982, when Sean Penn played the perpetually stoned Jeff Spicoli in "Fast Times at Ridgemont High." Nowadays, surfers are more likely to be seen as rugged individualists who symbolize a hip, forever-young lifestyle.

Hamilton, known for tackling the world's biggest, most dangerous waves, said the sport's public image — "a beach, coconuts on the sand, girls in bikinis" — is a good selling tool for advertisers.

"It represents a fantasy, but also a goal — someplace to get to," said Hamilton, whose new Wonderwall clothing line includes low-cost T-shirts, board shorts and surfing accessories.

U.S. surfing and skating stores generated about $7.5 billion in sales in 2006, a 15 percent increase over 2004, according to the latest statistics from the Surf Industry Manufacturers Association.

Quiksilver's chief executive, Robert McKnight, said authenticity is the key to selling surf wear.

"You have to bleed it in your DNA; you cannot fake it," McKnight said at his Huntington Beach office, which is decorated with surfboards and photos of giant waves. "These kids know which companies are cool."

Since its founding in 1976 as a maker of surfing shorts, Quiksilver's revenue has climbed to $2.4 billion. The company is still growing, but it's expanding at a slower rate because of increased competition and the slumping economy.

Surfing projects an image of glamour, fitness and environmental awareness, said Ward Davis, managing partner of New York-based Trivium Capital Management, which owns 2.8 million shares of Quiksilver.

"It has become more of a mainstream sport," said Davis, who sometimes surfs off the coast of New York's Long Island before starting work. "Companies are beginning to incorporate it in ad campaigns."

J. Crew is featuring surfers Buzzy Kerbox and Campbell Farrell on the cover of its summer catalog.

Abercrombie & Fitch sells Southern California lifestyle clothes through its Hollister unit, which targets teenagers by calling guys "dudes" and girls "bettys." Hollister now has more stores and higher sales per square foot than Abercrombie itself.

Even Wal-Mart Stores Inc. has gotten into the game with a line of young girls' sweaters aimed at the surfing crowd. (Quiksilver has sued Wal-Mart, claiming the logo on the sweaters is a copy of Quiksilver's Roxy trademark.)

Sales at Nike's Hurley International unit, which is geared toward the surfing and skateboarding market, increased 33 percent in the third quarter that ended Feb. 29.

Hurley "is connecting with our core consumer and with the broader action sports market," Nike Chief Executive Officer Mark Parker told analysts on a March 19 conference call.

McKnight said casual clothes are taking over shelves formerly occupied by dress shirts and ties at many stores.

He also said the industry will continue to grow around the world.

"We have this theory around Quiksilver that half of the world's population lives at or near the beach and the other half cannot wait to get there," McKnight said. "Everyone has a good experience with the beach."