Sleek suits hit the surf

Toss out your flower-power bikini -- 1980 marks the year that geometrics make their big splash! It's a season for checks and balances. Swimwear divides itself into stripes, cubes, checks, and diagonals, with the one- shouldered maillot stepping out as the star silhouette of the season. Suit shapes are sharply divided, 50-50, on either the vertical or horizontal plane. Designs are figure-flattering to shapes that don't require any camouflage.

There are more suits designed for the fuller figure. Jantzen is introducing a "Janfit" collection featuring a new fabric that promises extra curve control.

Sandcastle shows a softly feminine, crystal-pleated swimdress, toga-tied around the bodice to the waist, which both compliments and conceals.

On the other hand, swimwear is available at its briefest. The one-piece suit is definitely in -- but so much of it is missing.

Some one-piece suits are slit to the navel, and legholes have been enlarged to the point of being pornographic. Sides and backs have disappeared altogether. The season's briefest bikini comprised a ruffle for a bra and two ruffles held on by a string tie for the bottom.

For the more discriminating, there are some pretty swimsuits. Shirring shows up where colors are spliced together: down the front, on the sides, and around the bust. Prints streak up suit sides, giving the design an asymmetrical look.

Fashion's preoccupation with black and white for spring and summer spills over into swimwear. When not used in combination black or white becomes the background for hot-colored prints, again done in geometric shapes. Gottex offers one of the strongest black and white collections by playing with squares, making them multisize, and including a terrific cubed cover-up.

Solid color is important when linked with new swimwear fabric textures. Breaking away from smooth, silky nylon, designers have chosen pique, damask, seersucker, and ribbed surfaces. Cotton returns in the oldtime favorite puckersuit.

This season, there are no real trends in swimwear cover-ups. Many manufacturers are offering sportswear-oriented items (shorts, warm-ups, romper suits) to wear over a swimsuit. The idea is to sell practical, multi-use apparel.

Still, there is nothing more glamorous than a white lace beachcoat, worn over a fantastic black and white swimsuit, complemented by a glowing tan. Who said swimwear was supposed to be practical, anyway?