FASHION : Water Worthy : Men: Can leaner suits in off-beat patterns heat up swimwear sales? Retailers hope so, and promise the square-cut look will flatter less-than-perfect bodies.

Think of Elvis Presley’s square-cut knit bathing suit in 1961’s “Blue Hawaii” or Cary Grant’s narrow, belted knit number in the 1955 film “It Takes a Thief” and you’ll recognize the look of men’s swimwear for summer 1992.

Manufacturers are using these vintage designs as prototypes for a series of leaner, more versatile boxers. These shorts and other classic suits, including the belted bikini and the one-piece tank, are expected to be big fashion news on Southern California beaches this year.

Originally offered in black and white, many of the updated models are cut from colorful tie-dye, batik and other time-tested prints.

The men’s swimwear business has been off for several years, and many retailers are projecting that the design shift will increase sales by 20% this year. Most of the name brands sell at prices that range from $30 to $55, but many stores are carrying variations with their own labels, priced from $15 to $25. (Retailers say the average man buys two swimsuits a year in a favorable economy, one or none during a recession.)

“The guy who wants to be on the cutting edge will spend the $23.95 to get a new swimsuit,” says Mike McGinley, vice president and buyer at the L.A. Sporting Club. “But we have to offer him something new. Retro looks started last year and they continue to sell.”

The square-cut knit boxer, a shape popularized by Jantzen and Catalina in the 1940s, made a brief reappearance on California beaches in the late ‘50s and early ‘60s. Back then the style--using solid-colored wool and often belted to keep it from falling off in the water--was so heavy it turned its wearers into human anchors. The updated models are color-blocked or printed and use a cotton-spandex blend, a more breathable and lightweight fabric that resists water buildup and clings to the body.

The new, tight silhouettes have rendered the belt useless, but a number of manufacturers have kept them--and added antique buckles. Some are even belting bikinis.

“Square cuts look good on a heavier man or a thin man who might not feel comfortable in a bikini,” says Tyler Henderson, catalogue/merchandise director at International Male stores. He estimates the vintage style could be as much as 30% of his swimwear business this year.

Designer Jeffrey Gazelle, whose signature company has created an entire collection of retro-inspired swimsuits for Bullock’s Beverly Center, I. Magnin and International Male, says he first noticed the look on a young Ronald Reagan in a book on vintage swimwear design. “No one put out a style like that in many years, even though there are a lot of guys in their 30s, 40s and 50s who for whatever reason can’t wear a bikini and don’t want that California surfer look either.”

Gazelle says there is a practical element to the new square cuts: A bikini is fine for swimming and tanning, but inappropriate on city streets. The square-cut suit, like last year’s volley shorts, easily moves from sand to sidewalk.

At Speedo, known for its competition swimwear, square cuts are expected to represent up to 40% of the company’s volume in spandex suits this summer. According to Speedo’s Jamie Madden, the look attracts men with less than perfect bodies. “It’s a very forgiving fabric and style,” she says.

Speedo has updated the look in textured patterns, mini-checks, holograms, plaids and batiks from Bali.

Square-cut suits in batik prints are popular with younger customers, notes Ray Wills, men’s fashion director at Bullock’s. However, he says, other retro-inspired designs, like the belted bikini and the tank suit, look too new for the typical department store customer. “Most of our business is trunks and bikinis,” he says.

Tank suits, used most often for workout wear, are also gaining momentum.

George Erickson, owner of the Hollywood store By George!, says the tank suit (about $35) is “an item to buy for the gym that doubles as swimwear on the beach or at pool parties.” He says the store has sold the look in stripes, colors and even some see-through fabrics.

What’s sparking the retro swimwear trend? According to Madden, it’s a look that never left the beaches of St. Tropez, and American men are just getting hip to it again. She says the resurgence started in Florida, where vacationing Europeans reintroduced the style. “A whole new generation is seeing this look for the first time,” she says.

Not everyone, however, is comfortable with it. “It’s fashion, not mass America yet,” notes McGinley. “We’re still trying to get some people out of cut-off jeans.”