JUST ADD WATER SWIMWEAR GOES RETRO FOR THE HOT, HOT, HOTTEST NEW LOOKS.

Byline: Barbara De Witt Fashion Editor

Swimsuit designers have string fever.

In yet another salute to the '70s, those teeny string bikinis - many with triangle tops - are back, ready to hit the beach in tropical prints with hothouse flowers as well as touristy scenes taken from vintage Hawaiian shirts.

The season's island icon is the pineapple, the Hawaiian fruit that is not only a Victorian symbol for welcome but the fruit most associated with '40s Brazilian bombshell Carmen Miranda.

You'll find pineapples mixed with other fruits and flowers in the junior styles and served solo in the couture collections such Chloe's maillot, which plunges as low as Jennifer Lopez's infamous Versace dress. The latter isn't designed for swimming, yet it's already sold out at Saks Fifth Avenue in Beverly Hills, says spokeswoman Kari Miller, who adds that Ungaro's camouflage prints and Burberry's plaids are other best sellers.

Although designer-dress details have clearly influenced swimwear, it's really the stars who wear them who set the trends.

``Jennifer Lopez is probably the biggest influence in swimwear silhouettes this year,'' says Rebecca Virtue, whose Becca and Rebecca V. collections for Lunada Bay are sold at Nordstrom and Bloomingdale's.

``Not only the plunging neckline of that Versace gown but also the one- shouldered white Valentino dress she wore to the Golden Globes have been translated into swimwear. And then there's the music industry's glam-rock look that she's also part of that's reflected in swimwear.''

Virtue, 34, who's been designing swimsuits since she was 23, likes the sexiness of rocker details such as metal ear or nose rings or iridescent paillettes stitched onto a high-gloss fabric string bikini.

Also a fan of the rocker look is Joyce Azria, the 19-year-old daughter of BCBG president Max Azria, who now designs the BCBG Max Azria Swim collection available at its boutiques and also at Bloomingdale's.

``Although some of our suits are halters, including a plunging one- piece with the BCBG logo, I also added rocker bras that have an underwire to create a rounding effect and hipster bottoms ... but the itty bitty Brazilian bikini with triangles is my favorite,'' says Azria, whose collection includes a variation on camouflage as well as brights such as orange, turquoise and pink in a soft suede fabric that looks and feels like leather but survives in chlorine.

Although several designers are offering one-shouldered suits, Azria says the look creates bad tan lines and can't swim well, so she passed.

Ditto with the kitchy Hawaiian prints. ``They're fun (for teens) but I believe women don't want complicated prints.''

Kate Rice, fashion spokeswoman for Mervyn's stores, agrees.

``Unless you're under 18, you really don't want to be prancing around on the beach in a floral string bikini, and this year there are plenty of options that are figure fixers ... suits that diminish waists, hips and bottoms.''

One of those ``figure fixers'' is another '70s favorite, the one-piece suit with huge cut-outs at the waist line. ``It can be very sexy without exposing a lot,'' Rice adds.

Other new-again styles to hide less-than-perfect figures are blouson tops at Mervyn's and tankini suits with longer tops found in the Lands' End catalog.

For those who think the elongated boy-leg style will diminish thunder thighs, Rice urges caution: ``Boy shorts are not the hide-all that they appear to be and really look best on slim bodies.''

Hula prints, bikinis that have more strings than fabric? What's a mature pineapple princess to do?

A trip to the mall showed a sea of suits designed for women whose bikini days are past. Leading the lineup were Tommy Bahama's pastel tropical prints and Gottex's hibiscus-accented suits with matching jackets and sarongs to tie around the hips. Suit companies dedicated to whittling waists, such as the Miraclesuit by Swim Shaper, also offered slimming black suits with some Hawaiian punch splashed across the bodice.

Hair and makeup by Stephanie Hobgood of Frederic Fekkal Beaute de Provence, Beverly Hills.

Splashy new details:

--Tropical prints

--Camouflage prints

--Gingham and plaid

--Triangle tops

--String styles

--Shiny fabrics

--Plunging necklines

--Reversible bikinis

--Shades of turquoise, orange, pink

--Novelties such as beads and bangles

Try these 10 tips on for size

Sure, you could swim in your sarong or oversize shirt (over your suit), but people will talk. And you'll be so uncomfortable.

To get over those beach blanket blues, check out these camouflage tricks we found in Leah Feldman's newest book, ``Does This Make Me Look Fat?'' (Villard; $24.95).

1. Give yourself time to shop. Try on lots of suits and look at yourself critically from the front, side and rear. And look for Suitable Solutions hang tags that many manufacturers have on their suits indicating which figure type they're meant for.

2. Get the right fit. Always try at least one size larger than you think you wear. When suits are tight, the edges cut into any excess flesh and make bulges. However, if the suit is too big you'll soon be falling out of it, as swim suits stretch and lose their shape after a season of chlorine and hot tubs.

3. Look for high Lycra content. The more Lycra in the suit, the more it will hold you in.

4. Check the inside construction. Look for hidden features such as underwire bra support, bust enhancers, double linings or tummy-trimming panels.

5. No big prints. Small or spare prints are OK, but big prints pop out and make you look bigger. However, cleverly placed vertical and diagonal stripes and/or color blocks can slim.

6. Avoid shiny fabrics. Every lump and bump will shine in reflective fabrics, while textured fabrics will help conceal bulges.

7. Stick to the darker colors or tones close to your skin color. Remember that dark colors recede, making the figure appear smaller and skin-tone suits give the impression of an all-over monotone, always a winner.

8. Minimize your imperfections. Make your legs appear longer with the highest-cut leg you feel comfortable in; conceal tummy bulges with shirring across the front or a blouson top; create a longer torso with a tankini (two-piece with long top) or a suit with the new plunging V-neckline. Halter necklines also create a longer, slimmer torso, but may make your shoulders appear narrower.

9. Inspect the bra. Underwire push-up bras will boost a small bust, but most of the time they look unnatural - and they stay wet longer than the rest of the suit. If you're very full-busted, look for good support such as an unpadded underwire bra and consider a suit sized for long torsos, since your bust dimension can use up the extra fabric meant for a longer waist.

10. Let the skinny girls wear little boy shorts, skirts, modesty panels and ultra high-cut legs; those features may sound flattering but they're not. They'll make you look short and stubby, except for the legs that are cut so high, they showcase saddlebags. Ditto on anything resembling a thong.

- B. D.

Meet the model

Stuart is a 16-year-old first-year student at Pierce College in Woodland Hills who's been busy with TV, film and music when she's not studying.

In the short-lived Aaron Spelling production ``Titans,'' Stuart was a recurring guest star in several episodes. She played a spoiled seductress named Faith. Stuart will be seen in the syndicated series ``Xena: The Warrior Princess'' at 4 p.m. May 19 on KTLA (Channel 5) as a sacrificial virgin who gets rescued by Xena and taught how to survive in the wilds.

Stuart says it was exciting to travel to New Zealand for the ``Xena'' show, but laughs and says she's not like either of the characters she has played. ``In real life, the most outrageous thing I've ever done was wear white after Labor Day,'' she says with a chuckle.

According to Stuart, ``As an actress, I believe I have a responsibility to be a good role model for little kids, even if I am asked to be very sexually suggestive.''

In addition to her TV projects, Stuart has just completed filming a starring role in the big-screen action adventure ``Fangs,'' to be released at an undetermined date by Porchlight Entertainment. According to Stuart, ``It's a family film about a girl who saves her town from a ruthless developer.''

And she's recently signed a recording contract with EMI-distributed 2K Sounds in Woodland Hills and is in the studio working on her first CD, ``Achingly Innocent and Hopelessly Hot,'' to be released in 2002.

Born in: Sonora, Calif.

Sun sign: Leo.

Stats: 5 feet, 3 inches; wears a size 0 dress, size 7 shoe.

Web site: www.katiestuart.com

Favorite designers: BCBG, Bebe, Gucci and Prada.

Favorite mall: Fashion Square in Sherman Oaks.

Favorite Valley restaurant: La Pergola in Sherman Oaks.

Favorite foods: Pasta and chocolate cake.

Favorite music: 'N Sync. ``I'd love to do a duet with them.''

Her vocal inspirations: Mariah Carey, Celine Dion, Etta James and Aretha Franklin.

Instruments she plays: Violin, piano and flute.

Favorite actress to work with: Victoria Principal. ``She had to yell at me on 'Titans,' so she brought me a bunch of her beauty products to let me know we were still friends.''

Honors: Bay Area Filmmakers Association award for Best Dramatic Performance in a Feature Film and Temecula International Film Festival's ``Newcomer of the Year'' award.

Film credits: HBO's ``Frog and Wombat.''

Tips for aspiring actors: ``Get headshots, contact agencies, always be sweet and always persevere, because things happen for a reason. And get a good education.''

CAPTION} Photo:

(1 -- cover -- color) To portray a soap opera vixen, actress Stuart chooses a bikini with metal ring trim by Becca, $66 at Nordstrom, with a gemstone ankle bracelet, $220, from the Elyssa B. Design Studio in West Hollywood.

(2 -- color) In a sea of string bikinis, this tube-top style is a colorful option. It's $90 at BCBG Max Azia boutiques.

(3 -- color) Going for poolside drama is actress Katie Stuart in a daring one-piece suit, $109, by Joyce Azria the 19-year-old daughter of BCBG company president Max Azria. Stuart's accesorized it with Silhouette shades and a Liz Claiborne hat from Macy's. Read more about Stuart on Page 12.

(4 -- color) Camouflage-inspired prints are season standouts, particularly this halter nect maillot by BCBG Max Azria, #96.

(5 -- color) Hawaiian prints, such as this Hot Coles design, $50 at Mervyn's are making a splash this summer.

(6 -- color) Rebecca V. pust a little back interest in her one-piece suit, $70 at Nortstrom.

(7 -- color) Stuart is a pinapple princess in OP's ``Island Hopper'' string bikini, $67 at Bloomingdale's.

(8) No caption (girl in swimsuit)

(9) no caption (Katie Stuart)

Box: (1) Splashy new details (see text)

(2) Try these 10 tips on for size (see text)

CAPTION(S):

9 photos, box