FORT LAUDERDALE, Fla. — When Ravannah Schrack booked her latest cruise she knew exactly what she didn't want: flashy shows, formal dinners and competition for deck chairs around a pool. So, instead of booking on a traditional cruise line, the self-described un-tourist booked a berth on a cargo ship, her fifth such vacation. She got exactly what she wanted: solitude, simple meals and containers as next-door neighbors.

Cargo ships may not have spas with fruity facials, rock-climbing walls and water slides, spinning classes and planned shore excursions, but freighter enthusiasts rave about their trips. With only a handful of travelers on any voyage, there's no dress code for dinner and plenty of space.

"It's the un-cruise," said Schrack, a retired teacher from Vancouver, Canada.

"We like saying it's like staying on your own yacht with a captain," said Ranko Zunic, the owner of Maris Freighter & Specialty Cruises, a Connecticut company that books freighter travel.

Zunic's company is one of a small number that book the trips, and he sells between 200 and 300 annually. A California company, Freighter World Cruises Inc., books about 1,000 trips a year, and a third company, New York-based TravLtips, Inc. arranges about 200, most through Freighter World.

By comparison, more than 12.5 million people are expected to take traditional cruises this year. And the experiences are oceans apart.

On freighters, cabins are utilitarian. There are no 24-hour buffets or gourmet cooking demonstrations; dinner is usually a single option. Travel has to be booked far in advance, and while the cost is usually less per day, about $100, voyages are longer, so the trips remain costly. At the same time, cargo ships aren't in port long, nixing extended shore visits.

On a recent stop in Fort Lauderdale, the cargo ship CSAV Hamburgo was in port only about six hours before leaving for a trip up the East Coast. As a crane unloaded the ship's refrigerated containers, Capt. Szamrej Krzysztof said he typically has one to three passengers on five-week trips to North and South America.

Many of the travelers are retired or older. Florence Hansen, 73, of Spokane, Wash., has been on at least 10 freighter voyages and called traditional cruises "dreadful." But, Andre Reams, 45, of Arlington, Va., simply hates to fly. For the past decade he's been boarding the ships once or twice a year to travel to places he needs to go for work. The head of his own company, Reams said he gets a lot of work done on board because there are few distractions.

"The freighters work perfectly for me," said Reams, who has tried and disliked traveling by cruise ship.

Freighters aren't for everyone. Passengers must be in good physical condition as the ships don't have elevators, and because there is no doctor aboard, some ships set an upper age limit.

Joycene Deel, president of Freighter World Cruises, says her company screens potential clients to make sure they really want to travel by cargo ship.

Passengers who have to ask what to do with all the time or get bored easily might seek other trips, she said.