Bert Kilbride is a calm oasis on a dive boat loaded with fidgeting, giggling honeymooners and their shiny new gear. He basks in the sun, warming his bones like a contented old cat lulled by the familiar rhythms of the sea. But, I wonder, is he up for our photo shoot on the wreck of the Rhone 75 feet below? Yes, he is the man who ''discovered'' the Rhone in 1958 and the reason it is a national marine sanctuary today. But he is now an 85-year-old with a pair of bum knees, two hip replacements and gear left over from the Sea Hunt days. ''I've been diving since the day I was born, and I'll be diving until the day I die,'' the man who would be King Neptune insists. ''Really, I'm much better underwater than on land, and I've made this dive over 10,000 times. I could do it in my sleep.'' During our 50-minute boat ride from Virgin Gorda's North Sound through Drake's Passage in the British Virgin Islands, our two British divemasters deliver a well-rehearsed, tag-team rendition of Captain Wooley's Really Bad Day. On October 29, 1867, off Salt Island, a broken anchor chain, a misidentified late-season hurricane, a large boulder called Black Rock and a boiler explosion that broke the ship in two brought the 310-foot-long Royal Mail Steamship Rhone to its end. The result was 123 lives lost. At story's end, Kilbride is introduced. ''I didn't discover the Rhone; it was never lost. The mast stuck out of the water until the navy blew it up,'' Kilbride begins. ''I first dived it in l958 and recovered enough artifacts to fill a museum, including the skull of the ship's carpenter.'' ''Did anybody see the movie, The Deep?'' he continues. ''I was introduced to the producer, who was looking for a site. I brought him to the Rhone, and this is where it was done. My third wife, Jackie, became Jacqueline Bisset's underwater stunt double. And,'' he adds proudly, ''Bisset's white T-shirt was my idea!'' Kilbride adjusts his rudimentary orange horse collar and, with a little help, hits the water and descends without missing a beat. Hold up! I jump in and watch him slice through 10 feet of surface current without using the down line. How do those skinny legs move so fast? Doesn't he need to equalize? The man's a fish! We're greeted by a friendly swarm of parrotfish, angelfish, yellowtail snappers and a trumpetfish. I catch Kilbride so we can begin the photo shoot. I direct him to swim to several spots. He merrily misses all my marks, then settles himself carefully on a patch of sand. Typical renegade behavior for the man they call the Last Pirate of the Caribbean. If ever a man was born to the role, it's Kilbride. Untamed silver hair flies in every direction. He sports a crinkly white beard and plenty of gold earrings and bracelets. Clunky gold doubloons on fat chains are draped around his neck, and a lascivious twinkle in his eye sparkles as fathomless as the sea. All he's missing is an eyepatch and a parrot squawking obscenities. A New England Yankee by birth, Kilbride was drawn to Virgin Gorda for the warm, clear water and the treasures left behind centuries ago by Blackbeard, Henry Morgan and Sir Francis Drake. In the l960s, Kilbride bought a freehold on deserted Moskito Island (named for the Indians, not the bugs), to be near Anegada Reef, a treacherous 25-mile coral atoll where 225 known wrecks lie. Of those, Bert and his team discovered 138. ''Those were wild days,'' recalls Kilbride. ''I hired an all-girl staff and started Dive BVI, built the 12-room Drake's Anchorage. Never advertised, and we were always full.'' One year, Jean-Michel Cousteau brought Project Ocean Search (POS) to Drake's. Kilbride led divers on a hunt for artifacts that could help recreate the history of a wreck. ''Cousteau came back every year for 10 years, until his crew held a mutiny and demanded change,'' Kilbride recalls. ''He said we were the only operation where he signed up for 20 dives and got 20 dives. I was up all night, filling tanks with an old Volkswagen engine.'' Today, one of Cousteau's dive sites is called POS. During this time, Kilbride invented the resort course. ''Men came to dive the Rhone, and their wives sat on the beach all day,'' he says. ''I got sick of worrying that they were bored, so one day I taught 'em a few things, and we went to the shallow end of the Rhone!'' he laughs. ''They loved it! In 30 years, I never lost a diver. I even taught Dr. (Benjamin) Spock to dive when he was 70.'' In l970 Kilbride sold Dive BVI and moved to Saba Rock, a 3/4-acre spit of land in Virgin Gorda's North Sound. He had to haul in everything from the dirt up. He built a house out of driftwood and rock. There he began Kilbride's Underwater Tours (Dive With Pride With Bert Kilbride!). Wife number 5, Gayla, moved in after an island-style wedding on a rented 120-foot square-rigger pirate ship, with cannons firing. Gayla is a lively brunette, 34 years younger than Bert, and the one he calls the Keeper. She views her husband's escapades with obvious affection and few illusions, ''Bert enjoys the limelight, having people think we're sitting on millions in gold doubloons,'' Gayla offers and pokes him in the ribs. ''Tell her about the one that got away.'' The San Ignaceo, a Spanish galleon, was wrecked on Anegada Reef in 1742. ''I had a legal permit for five years to search for the cargo of platinum, gold, silver and diamonds, and in 1960, I went to Spain and hired an archivist to find the ship's manifest. But after 20 years of looking, I still can't find it,'' he laments. There's a fire in his eyes. ''At first I was after the money; now I'm obsessed with the need to prove it's there.'' In l989, Hurricane Hugo blew through the BVI and did enough damage to temporarily kill off the dive business, so Kilbride opened the Pirates Pub on Saba Rock. With its ramshackle decor (dollar bills stapled to the ceiling), the only cheap eats around (burgers and ribs) and the big-hearted Bert (with parrot) as host, the Pub attracted a diverse and loyal crowd. ''Yachties and boat captains, local drunks and celebrities like Robert DeNiro, Walter Cronkite and Geraldo stopped in,'' boasts Kilbride. ''Onassis and Jackie docked.'' The party lasted until 1995, the year of three hurricanes. ''Hurricane Luiz took all the rock out from the dock. We boarded the place up, and before we could fly out Marilyn struck and tore the roof off,'' Gayla recalls. Bert simply renamed it the Topless Bar. Later, a restaurateur from Hawaii bought the Pub. The Kilbrides moved to a condo on Tortola. At 85, Kilbride is still busy. For 10 years he's been working with the Drake Exploration Society to locate Sir Francis Drake's lead coffin from the waters off Panama and sail it home to England. He's teaching his adopted 11-year-old son Tyrel to dive. And, of course, he continues to search for treasure. ''My only fear is that I won't be around to realize my biggest dream,'' he confides. Seems he's drawn up elaborate plans for an underwater hotel just past North Point. ''From the ocean, all you'd see are big boulders. In the middle is a helicopter pad and boat slips. Split-level rooms, including 24 that are underwater, finger out on the edge. The whole thing is supported by hollow pilings so fish can move in.'' He just needs to update the plans slightly and get the financing. The man who's outlived his contemporaries, who won't eat his greens but loves his vodka, and who attributes his longevity to the love of young women, also has a plan for the afterlife. ''I've thought about being frozen just before I pass on,'' Kilbride confides. ''They could defrost me around 2062, and I'd renew my 99-year lease on Saba Rock, then maybe get in a dive or two. Wouldn't that be something!'' He throws back his head and laughs. For more information on visiting and diving the British Virgin Islands, click on the home page below.