An Eventful Voyage to the Colorful Caribbean Coast of Belize : Ships stop at Placentia and Belize City in this Central American nation, once a haven for pirates and refugees.

This tiny sliver of Central American coast, nestled between the Yucatan and Guatemala against the bright blue canvas of the Caribbean, was once called British Honduras. But it has been Belize since 1973 and an independent nation and member of the British Commonwealth since 1981.

Down here on the southern coast, light years removed from the funky farrago of Belize City and the tourist diving destinations at Ambergris Cay, it still looks like the end of the earth.

But tourists come here every winter aboard cruise ships, about the only way to get here except by pirogue or Maya Airways puddle-jumpers.

Placentia is the sort of place where worry seems superfluous. Weathered wooden houses perch casually on stilts to let the cool air circulate below. Chickens scratch in the sand; washing flaps on clotheslines; dishes turned upside down on drainboards dry in the sun. Women in plastic hair curlers gossip by a thick, narrow sidewalk 6 inches high and 6 inches wide, the town’s proudest possession, built by a long-ago Peace Corps worker.

Lumbering brown pelicans and sleek, fork-tailed frigate birds soar above the green and turquoise water that is punctuated only occasionally by a fishing boat. Rivers named Monkey and Moho slither down to the Caribbean from the Maya Mountains, where countless unexcavated ruins lie tangled in vines and foliage, only one clue to the unimaginable richness in this undeveloped country of 175,000, where the only apparent exploitation was the mahogany and logwood cut by the British 200 years ago.

There is a jaguar preserve in the Cockscomb Mountains north of Dangriga, and a wildlife sanctuary near Belize City protecting the jabiru stork, with a wing span of 12 feet the largest flying bird in the Western Hemisphere. In addition, the second-longest barrier reef in the world lies just off the coast. Rare black orchids grow along the jungle rivers, and long slender needlefish skim the surface of the sea like animated knives from a sinister cartoon.

For centuries this land has been a refuge, a hiding place, for the Garifuna, black Caribs descended from the intermarriage of African slaves and cannibalistic Carib Indians, who fled here from banishment on the island of Roatan off Honduras; for shipwrecked 17th-Century British sailors and unreconstructed Southerners after the Civil War; for Kekchi Maya from Guatemala, Caribbean pirates, sugar plantation laborers from India, mestizos from Mexico, tall blond Mennonite farmers from Northern Europe, Chinese storekeepers and Lebanese traders from all the raffish ports of the world.

They have all been simmered in a mixture not unlike the everyday Belize soup called “boil up,” made of root vegetables and whatever fish the cook can find, stewed together in water with no apparent seasoning. They percolate comfortably under a parliamentary government enforced by an unarmed police force.

While Belize City itself is on the hustle--whispers about a burgeoning drug trade can be heard, and unsolicited “guides” glom onto tourists to steer them to hotels or restaurants in exchange for kickbacks from the proprietors--the rest of the nation seems polite and even courtly to foreigners.

Only the little 96-passenger Caribbean Prince, from American Canadian Caribbean Line, stops at Placentia during its 12-day sailings around the cays of Belize, and on to dive centers such as San Pedro, along the Rio Dulce of Guatemala and the colorful towns of Punta Gorda and Livingston.

This casual, unpretentious little vessel with a shallow six-foot draft can anchor or come alongside almost anywhere. The lifestyle aboard is casual; shoes are not required at the family-style dinners served at long tables. There’s no bar; passengers bring with them whatever they want to drink and the line puts out ice cubes and mixers.

Best of all, every 10th cruise with the line is free, which keeps the loyal passengers--most of them past retirement age--coming back.

Cabins are simple to austere, with the lowest-priced, bottom-deck windowless cabins a claustrophobic’s nightmare. Cruise prices range $1,188-$2,310 per person, double occupancy, for the 12-day program. Air-fare add-ons are available, and passengers who book the Dec. 3 season inaugural get an additional 10% off.

Scheduled departures this winter are Dec. 3, 17 and 31, Jan. 14 and 28, Feb. 11 and 25, and March 11. Other ports of call include Belize City, Ambergris Cay, Laughingbird Cay and Punta Gorda in Belize, and Livingston and Lago de Izabal, Guatemala. The ship schedules frequent stops at remote cays for snorkeling and bird-watching.

While the Caribbean Prince is the only ship to call in Placentia, several other ships are calling in Belize City this season.

The 450-passenger Gruziya from OdessAmerica makes a weekly visit to Belize City on Wednesdays during its seven-day “Mayan Adventure Cruises,” operating round trip from St. Petersburg, Fla., from Oct. 23 to mid-May, 1994. Fares range $1,195-$2,295 per person, double occupancy, and $1,695-$1,845 for a single in an outside cabin. Air add-ons are available. Other ports of call include Puerto Cortes, Honduras, and Cancun, Mexico.

The 729-passenger Regent Sea from Regency Cruises also calls in Belize City during its “Land of the Maya” seven-day round-trip sailings from Montego Bay, Jamaica, between Jan. 1 and April 16, 1994. Fares range $1,185-$2,065 per person, double occupancy, plus air fare. Other ports of call include Cozumel, Santo Tomas de Castilla in Guatemala and Puerto Cortes, Honduras.

Special Expeditions’ 80-passenger Polaris cruises between Limon, Costa Rica, and Belize City, Jan. 8 and March 5; the nine-day cruise costs $2,980-$4,780 per person, double occupancy, plus air fare. The ship will also cruise between Belize City and Balboa, Panama, Jan. 18 and 28 and Feb. 9. The 13-day program includes some overland travel and costs $4,800-$7,800 per person, double occupancy, plus air fare.

To get a free brochure, see a travel agent or call American Canadian Caribbean Line (800-556-7450); OdessAmerica (800-221- 3254); Regency Cruises (800-388-5500), and Special Expeditions (800-762-0003).