Love chocolate? Imagine sailing to the Caribbean while sipping chocolate drinks, devouring chocolate desserts and listening to pastry chefs espouse the emotional and health benefits that come from eating chocolate.

You’re not in some kind of chocolate delirium. Radisson Seven Seas Cruises offers a “Chocolates in Paradise” voyage in December — one week of sweet-tooth indulgence that will have you throwing your diet overboard.

Or how about a cruise for bikers? In November, motorcycle enthusiasts can board Royal Caribbean’s Voyager for its “Hogs on the High Seas” trip to the Caribbean — seven days of best-beard contests, prize giveaways and custom motorcycles on display.

Themed cruises, popular more than a decade ago before fading from most cruise lines’ itineraries, are making a comeback. Many lines are offering sailings this fall and winter that range from kosher cruises for Jewish holidays to private concerts with ’70s rock stars and treasure hunts with the crew of the BBC’s version of “Antiques Roadshow.”

“There are so many different specialty themes that have appeal,” said Jennifer De La Cruz, a spokeswoman for Carnival Cruise Lines. “We don’t do a lot of them, but they do present an interesting marketing opportunity, and they’re quite enticing to individuals that have an interest in those subjects.

“Where else can you rub elbows with Kevin Cronin and see groups that you loved in your youth?”

Cronin, the frontman for REO Speedwagon, will be sailing with his bandmates on Carnival’s “Rock ‘n’ Roll Holiday Cruise” to the Caribbean in November. Members of Styx and Journey will join them for concerts and question-and-answer sessions.

But themed cruises have a broad appeal beyond rock stars and motorcycle riders. Luxury line Radisson Seven Seas, which has more than 40 themed sailings, offers lecture series on American history, discussions with PBS personalities and instruction on how to dance the tango. Crystal Cruises has 64 “enrichment programs” among its 95 itineraries, from architecture cruises in Europe to Smithsonian lecture cruises in Asia.

“There’s a trend toward intellectualism” on themed cruises, said Mike Driscoll, editor of Cruise Week, an industry newsletter. “Cruises used to be kind of vacuous, but now you’re seeing more demanding passengers on board. If they’re spending $10,000 on a cruise, they’re not going to be satisfied just eating, sleeping, drinking and seeing local monuments.”

300 dpi 6 col x 7.75 in / 295x197 mm / 1004x670 pixels Philip Brooker comic-book style color illustration of a woman looking back at a cruise ship with a thought bubble that reads "Oh my...There are so many cruises to choose from!". The Miami Herald 2002 With CRU-CRUISELINES, Knight Ridder by Jane Wooldridge

KEYWORDS: cruiselines travel cruise ship vacation comic viaje por mar crucero viajes vacacion barco illustration ilustracion grabado contributed mi brooker wooldridge 2002

Many cruise lines opted to drop themed cruises because of the time and expense of organizing them. Now, many are handled by third parties — travel agents or promoters who purchase cabin space and work with cruise lines to make sure additional meeting rooms also are provided. And rather than dedicate an entire cruise to a theme, most leave room for several hundred passengers to mix among those who are just along for the ride.

That’s what Carnival will do for its rock ‘n’ roll cruise and its popular western Caribbean sailing hosted by NASCAR driver Rusty Wallace on the Carnival Conquest in December.

“We usually use a couple of hundred cabins, which is a good number because it’s a 1,000-plus cabin ship,” De La Cruz said of the Wallace cruise. “You’re not overwhelming the entire vessel with a theme group.”

Even so, imagine sunning yourself on a warm afternoon while a group of bikers performs belly flops in the pool. On the “Hogs on the High Seas” cruise, you’re likely to see it.

It’s their annual belly-smacker contest.

“We take up about half the ship, but most of the other passengers say they have as good a time or better as our people,” said Dean Anderson, who organizes the biker cruises.

And most of them are first-timers. Anderson estimates that 80 percent of his clients have never been on a ship before boarding his cruises. It’s the theme they’re drawn to, not the sailing.

“A lot of them are not real inveterate cruisers,” Driscoll said. “They’re just people interested in these topics.”