It's one of those things I wanted to do from the moment I saw Errol Flynn leap onto the deck, polish off 35 bad guys with his sword, swoop up the about-to-be ravished heroine and swashbuckle back to take command of his crew and his woman.

The ship sailed off, the curtain fell and I shuffled out hooked on the romance of ship life in the olden days.

An inappropriately long number of years later, I finally gave in to that longing and signed up for a one-day "sneakaway" cruise on the Mystic Whaler, a replica of a 19th- century two-masted schooner that sails the Chesapeake Bay each spring and fall.

It was sweet surrender -- from the moment her casual and friendly crew of five greeted the passengers with a breakfast of orange juice, flapjacks, bacon and coffee to our graceful return at day's end. A special trip to nowhere special, just lazin' round the Bay.

The adventure began as the first mate cast off and we helped the crew set sail. Then, well under way, the captain cut the motor and the magic of those first moments after the sails are up and the ship is noise-free took over. There's little else that has such an instantaneously calming effect. It was minutes before I heard anything at all -- and that was simply the water slapping against the hull.

We lounged and gamed, and after a while I got into the crewing spirit again. (The crew encourages everyone to help sail the ship and lets passengers, including children, take a turn at the helm.)

The bos'n told me to haul in the jib sheet -- pull in the rope attached to the most foreward of the four sails. Then it was clear I needed a lesson on coiling up the line and securing it to the cleat ("making a gasket").

We explored the staterooms (she sleeps 44 but can handle 60 people on day trips), the tiled showers and the galley, and tried to "learn the ropes." We found out more about the ship: She's 100 feet long with dummy gun ports painted on the side -- an old Yankee trick used to discourage pirate attacks. Many touches reach back to the whaling days -- a "cutting-in" stage (now used for swimming) and brick try-works converted to an on-deck barbecue.

We watched as the cook prepared hamburgers over the charcoal. He also served up a full-bodied pea soup, cheese, hand-cut cole slaw, chips, salad fixings, condiments and fruit cocktail. Eating on deck in the salt air surpasses all other al fresco dining.

After lunch, we all got down to some serious relaxing. Lounging beds dotted the decks and cabin roofs. We each grabbed one or two and slept, sunned, snoozed, mused, dreamed, read and slid into conversations with fellow passengers. Some of them had boarded the night before to sleep over and give their kids a chance to sing sea chanteys and hear tales of white whales, giant squid and pirates.

Most people seemed to fall asleep at one point or another during the balmy and tranquil day, including me. Dips and chips arrived at 3:30, along with iced tea, coffee and hot chocolate, and our course was set homeward shortly after.

We were totally relaxed; even the wind was resting, leaving us becalmed at times. I returned from a day of going nowhere and doing nothing and luffing it. YO HO GO The Mystic Whaler sails from the Annapolis City Dock for one- and two-day cruises from this weekend through June 26, and again from September 1 through October 30. Prices range from $49 for the one-day sneakaway to $199 for top- of-the line accommodations on the two-day cruises. The two-day cruises, with two overnight sleeps, make stops at such Bay ports as St. Michaels, Oxford or Cambridge. Arrangements can be made through the Mystic Whaler, 7 Holmes Street, Mystic, Connecticut 06355. Phone 800/243-0416. FUN FOR SAIL If the rich can buy them, the poor can rent them! Here's where to rent trawlers and sailboats that let you lie around while someone else does all the work: WASHINGTON MARINER SAILING SCHOOL -- Belle Haven Marina, Alexandria 22307. 768-0018. YACHT'S AMERICA -- Fort Washington Marina, Fort Washington, Maryland 20744. 292-1300. ANNAPOLIS AREA INTERYACHT -- P.O. Box 49, Annapolis 21404. 261-2292. NAUTILUS CHARTERS -- Galesville, Maryland 20765. 261-5570. ANNAPOLIS BAY CHARTERS -- Horn Point Marina, 121 Eastern Avenue, Annapolis 21403. 261-1815. CHESAPEAKE CRUISING -- 396 Riverside Drive, Pasadena, Maryland 21122. 301/437-2123. C&C CHARTER -- 1656 Homewood Landing, Annapolis 21401. 301/757-0707. LARSEN YACHT SALES -- P.O. Box 48, Annapolis 21404. 261-1035. PRIMA DONNA SAILING -- P.O. Box 821, Bowie 20715. 262-9108. FANTASY BAY CHARTERS -- 213 Eastern Avenue, Annapolis 21404. 261-1170. SUN & SEA YACHT CHARTERS -- 301 Fourth Street, Annapolis 21403. 858-5651. EASTERN SHORE EASTERN SHORE YACHTS -- Box 216, Oxford, Maryland 21654. 301/226-5571. LADY KATIE -- P.O. Box 232, Tilghman, Maryland 21671. 301/886- 2630, 886-2459. BALTIMORE NAUTICO LTD. -- 402 Key Highway, Baltimore 21230. 301/962-1171. PORT BALTIMORE -- 301 Light Street, Baltimore 21202. 301/727-3113. NORFOLK ROVER MARINE -- 1651 Bayville Street, 23503. 804/583-1470.