On the Chesapeake Bay, 8 a.m. Sunday, June 10: Howard Polster, 48, stood at the water's edge at Sandy Point State Park on the western shore just north of the Chesapeake Bay Bridge. He looked across the great bay toward Kent Island and Hemingway's Beach, 4 1/2 miles of swift-moving currents away. "I could barely make out the other side," he says.

Polster looked toward the bridge, a giant, blue apparition within touching distance, it seemed. "It towered over us, and then I thought of the deepness of the water and how many hours I'd need to swim without resting (a greater challenge for Polster, who's diabetic). If you rest, the current takes you off course."

Kathleen Trainor, 29, looked up at the bridge, too. "I was terrified. I wanted to run home and hide under the bed." For weeks before the Bay Bridge Swim, Trainor had driven over the great structure slowly, casting timid glances down at the water -- she knew it was deep, too -- her fear picking up rather than abating with each drive.

Now it was too late: The race had started, 800 people charging the water, thrashing, fighting for room to swim. The Bay Bridge Swim to benefit the American Diabetic Association was on. "It was like a salmon run at first," Trainor says, and very quickly she lost sight of her sister, Theresa, 28.

Then, silence and loneliness replaced the frenzied start as the enormity of the bay swallowed the swimmers, almost invisible specks on a great seascape. "I had the feeling I was completely alone out there," Polster says, remembering how he swam toward the bridge for half a mile then cut hard left, swimming between the spans.

The bridge became a comfort then to Kathleen Trainor. "I couldn't see a soul, so I would turn my head both ways and look up at the pillars. Stay between the spans, I thought. And then I could see the pillars moving slowly by." Four miles to go.

On the far shore, Fletcher Hanks surveyed the scene as safety boats crisscrossed the water. "When I started this swim seven years ago, we had a boat for each swimmer," he says. "All two of them. But I knew we would have more in time."

The bay was part of his consciousness. Hanks first swam these waters in 1921 when he was 3. In the '80s, they helped him become a champion -- in 1985 and 1986 he held the United States Masters record for the 10-mile swim in the 65-70 age group. To round out his exercise in 1986 Hanks started doing "Tin Mans," swimming 1.2 miles, biking 56, running 13.1.

"Cut right some," he yells in the direction of Sarah Connick, much too far for her to hear, but she seemed to hear anyway. The current had been tricking her. Sarah looks up at the spans again between strokes.

"When I started training in 1986," Connick, 27, says, "I thought I could never do this even though my first memories as a child are so tied in with swimming." Three thousand to 5,500 yards of laps in a pool, three times a week she trained. "It's a matter of personal achievement, you see."

On this day, hundreds of people fought their fear, found their courage and swam the bay; I'm sure every one of them was fulfilling a dream driven by a memory. What a personal achievement.

You can do something like that, too. Be ready for next year's Bay Bridge Swim. Or, if that's a little too ambitious to think about right now, how about actually competing in a somewhat shorter swim event next month? Like maybe two-lapping a pool or forming a relay team?

United States Masters Swimming (which means you must be 19) has 12 affiliated clubs around the Beltway, and these people have a good time as they swim their way to fitness. "Our emphasis is fitness through competition," says Joan Leilich, registrar of the coordinating club.

The clubs sponsor events, and there are three you could participate in right now if you're game:

July 1, there's a 1,500-meter competition at the spanking-new outdoor pool at the Rockville municipal swim center. Whatever your age, there's a heat for you.

July 8, the D.C. Department of Recreation Masters club is sponsoring a smorgasbord of events for just about all skill levels at Hains Point pool in East Potomac Park: 2 lengths, 4 lengths, 15 lengths, all strokes, freestyle and relays.

July 28-29, lots of time to get ready for these 14 events sponsored by the D.C. Masters at Oak Marr, the Fairfax County indoor pool.

To swim in a Masters event, you must belong to U.S. Masters Swimming, which costs about $20. Though you usually can join at an event, it's just as easy to write for a membership application and a list of clubs in the area. Send a stamped, self-addressed envelope to Joann Leilich, Registrar, Potomac Valley Masters, 4913 Kingston Dr., Annandale, Va. 22003; (703) 354-2130.

Event fees usually run around $6. To compete, contact the event coordinator:

July 1, Rockville: David Diehl, 12511 Littleton St., Silver Spring, Md. 20906, (301) 946-0649.

July 8, East Potomac Park (Hains Point pool): Call Hank Steingass, D.C. Department of Recreation Masters, (202) 483-9330. Steingass says 40 of the club's 105 members are over age 40.

July 28-29, Fairfax County: Write D.C. Masters coordinator Ed Kenehan, 13536 Straw Bale Lane, Darnestown, Md. 20878, (301) 948-2135.