Themed cruises can float just about every boat

If you think that cruises are only about sailing the high-seas, eating at endless all-you-can-eat buffets and making quick pit stops at remote islands, think again.

Theme cruises, where groups of like-minded travelers join to discover new destinations, are growing in popularity --and are luring in groups with some decidedly unique interests.

Recently, Carnival Cruises joined forces Twisted Pictures to create the SAW at Sea Cruise, bringing together torture-porn aficionados and cruise-lovers. There are also cruises for psychics, nudists, lovers, crafts, art, music, book and politics --and more.

"Theme cruises are like conventions, a reason for people of any affinity to come together for fun, discussion and special events," explains Paul Motter, editor of CruiseMates.com.

The number of theme cruises has grown significantly in recent years. "The list of possible themes runs the gamut of human interest: politics, music, lifestyle, cuisine, wine appreciation or Alcoholics Anonymous," Motter says.

These cruises generally come in two forms: large group tours placed on a ship alongside regular holidaymakers, and chartered cruises that take over the entire ship, allowing for total immersion.

Motter suggests choosing the latter option whenever possible, for a more complete themed experience. "It is more immersive and gives the promoters control over the scheduling of everything from meals to entertainment, events, exhibits and even itinerary."

Activities and attractions are often centered on the ship itself, with the destinations playing a secondary role in the overall experience. While most are full-ship charters, some may be chartered on a ship alongside traditional passengers, so be sure to research the trip thoroughly before booking.

For example, about a dozen different nude, gay, swinger and other "alternative lifestyle" cruises operate every year in countries all over the world, Motter says.

For music lovers, a cruise mixes the most appealing elements of a music festival with the luxuries and comforts of a holiday resort. Far from the traditional cruise ship acts, these theme cruises attract notable musicians of every genre, playing on purpose built stages with state-of-the-art equipment.

Over the past few years, popular artists like ZZ Top, Foreigner, R. Kelly and Weezer have taken to the waves to delight music fans while en route to exotic destinations.

"It is not uncommon for a music cruise to have as many as 25 different groups on board," Motter says. "The music starts in the afternoon and continues until the wee hours, often with two or three different stages in use at the same time."

Education is also a big lure for passengers who want to bypass the pool and get intensive instruction on a hobby or interest.

Many culinary cruises, for example, employ Michelin-starred chefs to create exciting and innovative dishes for guests, while sailing to culinary hotspots like southern France or the Mediterranean.

It's even common on smaller vessels for a chef to take the guests shopping at a local marketplace to buy fresh ingredients from the regional farms and prepare them for that evening's meals, Motter notes.

"One line, Oceania, has two new ships with a series of culinary cruises where guests can learn from top chefs and even practice recipes in a special classroom with food preparation work stations for the students," he says.

There is a downside for these types of cruises. Themed cruises don't run regularly, making them difficult to fit into a set schedule, and because they cater to a select market, there is less chance to find last minute bargains.

But themed cruise lovers say the extra benefit of being in a limited space where you can really mingle with like-minded enthusiasts and, at times, rub elbows with top celebrities in the field makes these cruises all the more special.