Instructor Eitan Newman is perched behind Sea Explorer’s wheel, dressed in what looks like the top half of a Left Shark costume.

“In case you don’t see any other sharks,” he offers, before beginning his briefing on a highlight of Blackbeard’s Bahamas adventures: lunch with the sharks at a site off the foot of Eleuthera called Split Coral Head.

Newman need not have worried. Before we even splash in, one brand-new diver is nervously peering over the side, hollering, “There are sharks down there!”

No kidding. By the time our entire complement of 21 divers is arrayed on the sand beneath our 65-foot sailboat, eight to 10 Caribbean reef sharks are circling. This ain’t their first rodeo — they know what’s coming. Like an underwater New Year’s ball-drop, a large chumsicle begins its stately descent down the line, guided by a now more appropriately outfitted Newman. The sharks are beautiful, gliding through clear water and long shafts of sunlight, a serene yet still awe-inspiring scene — that is until one hooks a tooth in the frozen chum, and all heck breaks loose. It’s only a momentary frenzy, but it gets everybody’s adrenaline up, sharks and humans, before the experience concludes with a free-for-all hunt for shark teeth, the only thing you’re allowed to take with you from this pristine underwater realm.

YO HO, YO HO
Blackbeard’s sloops aren’t like most liveaboards. The 55-ton sailboats have berths for up to 22 divers and five crew. This is boat camping. Primitive boat camping — to say that quarters are close is to say that the Sistine Chapel has a pretty nice ceiling. But the food is fantastic, plentiful and delicious — it’s like Mom came camping too! — and the young crew, while professional and task-oriented, is friendly and fun- loving. The weeklong dive party is great for solo or younger divers, or the young at heart: Our trip included wannabe buccaneers from 12 to 70-something, from grizzled dive vets to families just getting certified.

Blackbeard’s slogan is “Twice the fun ... half the cost,” and that’s literally true: Two luxury liveaboards ply the same sites you will, except those divers are paying more than twice as much to submerge at lovely spots like Monolith, off Eleuthera. Its namesake is a sweet little pinnacle at 80 feet or so, a perfect Cleopatra’s Needle perched at the edge of one of the Bahamas’ trademark plunging walls, easy to circle round and round until you’ve covered every inch. Zigzag back up toward an eel garden on the sand — stalking them is good pirate practice — or fin across a coral gulch and watch the wall recede beneath you.

Sunny, relaxing, easy-peasy — that pretty much describes the diving in Exuma Sound and off southern Eleuthera. Intriguing terrain beckons everywhere, from room-size coral heads like Tunnel Rock, pocked with swim-throughs wide enough for giant loggerhead turtles to join you, to lovely little bommies at Lobster No Lobster, southeast of Nassau, that unfold for your inspection like the petals of a flower. Reefs are cut through with sand channels that sometimes run right off the wall and into the abyss, as at Cut Through City, or lead to secret small caves, as at Madison Avenue.

THE YIN AND THE YANG
That’s the Blackbeard’s twist: low rent, big payoff. You’re diving the same sites as those luxe liveaboards, three to four times a day, but you’ll be berthed in dorm-style bunks, where you can neither sit up nor perhaps fully stretch out. The food’s great, but you’ll be balancing your plate on your knees, wherever you can find on deck to perch. (No one said the pirate life was easy.)

But it’s more than that. You might feel closer to the sea and sky — and stars — on a sailboat than you ever have, which makes for unforgettable moments, like when someone hollers, “Fish on!” and everybody rushes the stern in time to see a flash of aqua running along the port side.

It’s a mahi. Our jubilation is premature — after a brief struggle, the fish slips the line and gets away at the last second. Five minutes later somebody yells, “Pilot whales!” There’s a whole pod on our stern as we start to make the four-hour crossing from the Exumas to Eleuthera; they don’t stick around either. “We’re being teased,” says first mate Chris Lawrenson.

On another evening we’re gifted with the elusive green flash at sunset — just a tiny emerald nugget, but it was there. Forty-five minutes later a glowing orange moon rises over the bow, where divers cluster in small groups, laughing and talking softly, enjoying the rum punch that flows freely once the day’s dives are done. A beach bonfire near Cape Eleuthera on our only port night turns into the best party I’ve been to in years. And nobody wanted to go home after the final night's bash with the crew at a Nassau bar with an unreal house band — "the best dive of the week," said one graybeard.

A pirate's life indeed.

NEED TO KNOW

WHEN TO GO
The Bahamas is a year-round dive destination; Blackbeard's itineraries are weather-dependent, so you may dive any of dozens of sites off Nassau, the northern Exumas or southern Eleuthera.

DIVE CONDITIONS
Water temps range from 72 to 77°F in January, when a 5 mm might not be too heavy, to 81 to 85°F July to September, when a bathing suit will suffice.

OPERATOR
Blackbeard’s Cruises (blackbeard-cruises.com) operates two 65-foot sloops, Sea Explorer and Morning Star; each has 18 dorm-style bunks. Weeklong cruises include all meals and beverages (alcoholic and non) and up to 19 dives per week, fewer if weather permits extras like a run down to Staniel Cay to snorkel the beautiful Thunderball Grotto, featured in the James Bond movie of the same name, or to visit the famous swimming pigs of nearby Big Major Cay.

PRICE TAG
It’s $979 per week per person, not including port fees and crew tip.