What Is the Frequency of a Sound Wave

Once the epitome of elegant travel, cruising nearly vanished with the dawning of the jet age in the 1960's. But just as martinis and cigars are making a comeback, so too is cruising— albeit with a more youthful, adventurous spirit. In the course of a day you might find yourself venturing up the Amazon by Zodiac, soaking in a thalassotherapy pool in the ship's spa, and dining on ahi tuna seared by a world-class chef. Here are the most exciting trends, and our picks for the cruise lines that do them best.

SERVICE AT SEA
On ultra-luxury ships, cruise staff will go to almost any length to pamper passengers.
Seabourn Cruise Line, for example, prepares suites for its guests by collecting their requests before they sail. That has entailed stocking Yoo-Hoo chocolate drink for a guest in Scandinavia and hand-delivering an orthopedic pillow to a guest docked in Singapore.
When Radisson Seven Seas' Song of Flower guests journeyed to India to see the Taj Mahal, they were greeted at the 19th-century palace where they stayed by men on horseback, clad in turbans and silk tunics. Young women on elephants tossed rose petals over the guests as they approached the entrance. Inside, they dined on tandoori lamb and rice flecked with flakes of real silver.
On Crystal Cruises' penthouse decks, guests are assigned a European-trained butler, who will pack and unpack their luggage, give a last-minute pressing to an evening dress, or coordinate an intimate dinner on their private penthouse veranda.

PRACTICAL TIPS

Consult a travel agent who is accredited by the Cruise Lines International Association (CLIA)— meaning that they have completed a cruise training program and have sailed on or visited many ships. To find one in your area, visit CLIA's Web site.
Most lines offer early-booking discounts, ranging from 5 to 40 percent, if you book at least 90 days before the sailing.
Ask your prospective cruise line whether they'll reduce your fare if they lower rates after you book. Many lines will.
When you buy a fly/cruise package, sometimes cruise lines book you on inconvenient airline routings or are unable to make advance seat assignments. Ask your travel agent whether the line has a deviation desk, which can customize your airline arrangements for a moderate surcharge.
If you're sailing with children, inquire about the availability of counselors. Some ships' programs are in full swing only during peak family vacation seasons.
To prevent seasickness, avoid heavy foods and alcohol a few days before departure. You can also ask your physician to prescribe a Reliefband, a new product thought to control nausea by modulating nerve activity through a mild electric charge.

BRAVE NEW PORTS OF CALL
Cruise lines are reaching new latitudes and longitudes, going where few big ships have dared to go.
Costa Rica When the Wind Song first skims Costa Rica's Gold Coast in December, Windstar (800/258-7245) will be the only major line with weekly cruises here. Onshore, slip into a harness attached to a pulley and cable and go "zip-lining" among the treetops to get a sloth's-eye view of the rain forest. Or venture into Rincón de la Vieja National Park and give yourself a facial mask using mud from the Miravalles Volcanic Area.
Croatia After several war-torn years, the picturesque walled town of Dubrovnik is back on Seabourn Cruise Line's schedule (800/929-9595). Sail into the medieval city's harbor and spend the day roaming Dubrovnik's main thoroughfare, the Placa, one of the world's most beautiful streets.
Namibia and South Africa As the sun sets on the dunes of the Namibian desert, chefs grill fresh seafood over open flames for Silversea passengers (800/722-9955). After dinner, the polyrhythms of African music fill this natural amphitheater. The journey continues down the Skeleton Coast, which teems with wildlife, and on to South Africa.
South America Crystal Cruises (800/437-3111) makes its first expedition here this month, departing from Valparaiso, Chile, and stopping in Ecuador and Peru. Hike the Andes with an archaeologist on the two-night trek to Machu Picchu.
Tahiti Radisson Seven Seas' newest vessel, the Paul Gauguin, may well be the most luxurious ship plying the waters of French Polynesia when it sets sail in January (800/333-3333). Designed to capitalize on Tahiti's natural splendor, the vessel has private verandas off half its cabins— the better to experience the brilliantly clear lagoons, dramatic volcanic vistas, and lush foliage. A variety of experts on French Polynesia will be on board to enrich the seven-night journey from Papeete to Rangiroa (in the remote Tuamotu Archipelago), Raiatea, Bora-Bora, and Moorea.
United Arab Emirates Cunard's Sea Goddess II will take you from the oil-rich deserts of Muscat to Kuwait City, beginning next October (800/528-6273). In Oman, explore mosques, palaces, and spice markets.

THE FLOATING GOURMET
Say good-bye to baked Alaska and beef Wellington. These cruise lines have moved on to West Indian lamb curry and salmon in green peppercorn sauce.

Crystal Cruises 800/446-6620. Some of the world's preeminent chefs whip up special dinners and share recipes at cooking demonstrations on select sailings. Sommeliers assist in wine selection from the most extensive cellar at sea.
In addition to its elegant main dining rooms, the Crystal Harmony has a Japanese restaurant that dishes out tempura and fresh salmon with shiitake mushrooms, and an Italian restaurant that serves specialties from seven different regions.

Seabourn Cruise Line 800/929-9595. From seared sea scallops on a bed of spinach and potatoes with saffron sauce to pheasant breast with lingonberry cakes and champagne cabbage, this line specializes in adventurous updates on classic dishes, with an emphasis on local, seasonal fare. They'll even deliver dinner to your suite, course by course, with white-glove service.

Silversea 800/722-9955. Master chefs from Le Cordon Bleu Culinary Academy join Silversea's expert chefs and sommeliers on six 1998 sailings to host cooking presentations and wine tastings. Chefs design special menus adapting classical techniques to the cuisine of the port the ship is calling at, be it in Bombay, Haifa, the Maldives, or Phuket. Silversea also has the dangerous distinction of offering unlimited champagne and caviar.

LAND AHOY
Next year's shore excursions are more intriguing than ever.
Cunard 800/528-6273. In 1998, Sea Goddess II adds two Southeast Asia day trips. In Indonesia's Spice Islands, guests tour museums and forts, dine on the veranda of a villa, then wander the grounds of a 300-year-old nutmeg plantation. On the ship's junket from Singapore to Phuket, they board longboats to Dusit Rayawadee, one of Thailand's nicest resorts, to snorkel, swim, and lunch in a beachside cave.
Marine Expeditions 800/628-8747. This line vows to make the ends of the earth affordable and accessible. Voyage to Russia's Kuril Islands, where few outsiders have set foot. Hike active volcanoes and hot springs and meet villagers in the Pacific's "ring of fire." Or take a Zodiac excursion down the tributaries of the Amazon.
Royal Caribbean International 800/327-6700. Sample some of the best golf courses in the Pacific Rim on RCI's new golf trip to Hawaii. Back on board, golfers can practice their swings on the ships' 18-hole miniature courses, complete with traps and water hazards.
Special Expeditions 800/762-0003. You might find yourself stepping over sea lions and iguanas, albatrosses and red-footed boobies, as you explore Ecuador's Galá pagos Islands, led by experts on the area's wildlife and ecology. On Special Expeditions' summer journey to Sweden, founder Sven-Olof Lindblad employs locals to give insider tours of villages in the Stockholm Archipelago.
Zegrahm Expeditions 800/628-8747. Zegrahm prides itself on guides who are leaders in their fields: your trip might be accompanied by the world's foremost authority on seabirds or the first woman to ski the more than 800 miles from Patriot Hills to the South Pole. Examine Aboriginal cave paintings with an archaeologist in the Kimberley, the remote northwest region of Australia; or explore the far reaches of the Antarctic by Zodiac.

SHIP OUT AND SHAPE UP
Overindulged at the midnight buffet?Most ships now offer redemption in the form of health-conscious cuisine, exercise programs, and spa treatments.
Celebrity Cruises 800/437-3111. Celebrity's beautiful AquaSpas, inspired in some ships by Japanese gardens, in others by Moorish palaces, are a good reason to sail on one of their latest vessels, the Century, the Galaxy, or the brand-new Mercury. Target different muscle groups as you migrate from station to station in the cross-shaped thalassotherapy pool, or soothe frazzled nerves in a hydrotherapy bath of seaweed and essential oils. But the AquaSpa's most distinctive treatment is Rasul, derived from an Asian ceremony: couples lather each other with therapeutic mud as aromatic herbal steam wafts around them; then a masseuse steps in to finish the job.
In the fitness center, personal trainers design individualized aerobics and weight-training programs. And Celebrity's "lean and light" menu, created by Michel Roux, whose Waterside Inn in England has three Michelin stars, makes it a little easier to resist temptation.
Norwegian Cruise Line 800/327-7030. Barrel down the 3,292-foot summit of White Pass in Alaska on a mountain bike. When you reach the 15-mile coast, the grade is moderate, allowing for stops to photograph waterfalls, the White Pass railroad, and the dramatic mountains.
Princess Cruises 800/421-0522. Start your day with a no-impact cardiovascular workout in the swim-against-the-current lap pool on the new Grand Princess, the largest, most expensive cruise ship ever built. Later, shimmy off your dinner in the disco, lofted 17 stories above the sea and reached by a moving sidewalk.
Radisson Seven Seas 800/333-3333. When the Paul Gauguin is inaugurated in January 1998, it will mark the first time that a Carita Spa opens at sea. While many cruise lines' spas lack distinction, the Paris-based Carita has attracted customers such as Catherine Deneuve and Isabelle Adjani in its 45-year history. Besides the usual battery of spa treatments, Carita has expanded into the realm of exercise machines and toning and bodybuilding classes. Windstar Cruises 800/258-7245. Light-cooking guru Jeanne Jones's Sail Light and vegetarian meals are so flavorful you might forget you're being virtuous. Wake up to blueberry blintzes (139 calories, 4 grams of fat); have a seafood paella lunch (393 calories, 5.2 grams of fat); and save room for the lemon custard cake (245 calories, 5.6 grams of fat).

CRUISING WITH KIDS
Cruise lines have developed creative, age-specific programs that allow parents to pursue their own adventures.
Disney Cruise Line 407/566-7000. Disney's first ship, the 2,700-passenger Disney Magic, sets sail March 12, and promises the most extensive and innovative children's activities at sea with its Oceaneer's Club. Each night there's an original musical starring Disney characters. Not only do kids meet the actors; they can also put on their own shows, dipping into Disney's costume closet.
Holland America Line/Westours 800/426-0327. Among its most intriguing offerings, Club HAL has specially designed programs for young adventurers on Alaska sailings. There are rain-forest hikes and kayaking expeditions, as well as a visit to the Alaska Raptor Rehabilitation Center in Sitka, where children can observe recuperating bald eagles and owls.

BRAIN WAVES
And you thought you'd be lying at the pool. . . . The most enlightened cruise lines offer ample opportunities for you to expand your mind.
Cunard 800/528-6273. Back to school. Between sunrise and sunset, you might hear presentations by a novelist, an ambassador, a jazz historian, and a Metropolitan Museum of Art curator.
Holland America Line/Westours 800/426-0327. Authorities on European history and culture share their wisdom with passengers aboard European voyages in the Flagship Forum lecture series.
Natural Habitat Adventures 800/543-8917. Eight guests join a marine biologist and a marine engineer as they research dolphin behavior in the Bahamas aboard a double-masted schooner.Seabourn 800/929-9595. Commentator David Brinkley, author Peter Mayle, and astronaut Walter Cunningham are among the lecturers who have participated in Seabourn's Enrichment Program. Watch for Edwin Meese, Rex Reed, and Walter Cronkite in 1998.
Swan Hellenic Cruises 800/426-5492. Visit far-flung ports, from Sri Lanka to Brunei, with the foremost experts on the regions, aboard this line's newest luxury vessel, the 388-passenger Minerva. The lineup of speakers is peppered with Oxford fellows and titled gentry. For example, Britain's former ambassador to Syria and Saudi Arabia will accompany a spring sailing in the Levant.
World Explorer Cruises 800/854-3835. Sail up to a mammoth tidewater glacier as it calves 100-foot chunks of ice into the sea with a sound the Alaskan Indians called "white thunder"— a detail your ship's geologist will expound upon. Later, when you sight an Eskimo totem pole, an anthropologist can answer questions about its symbolism. And for those they can't answer, there's the Universe Explorer's library— the largest one afloat, with 15,000 volumes.

ROLLING DOWN THE RIVER
A leisurely river cruise allows you to dock at small villages and sidle up to local culture.
Abercrombie & Kent 800/323-7308. Scout for rose-colored dolphins on the Amazon with a naturalist, or traipse through tombs and temples in Egypt with an archaeologist. A&K's agile 100-passenger expeditionary boats are the best of their breed, with botanists, zoologists, and archaeologists on board.
Peter Deilmann EuropAmerica Cruises 800/348-8287. This line offers 150 itineraries on just about every navigable river in Europe, aboard vessels with a 21/2-to-1 passenger-to-staff ratio. Next year, their Königstein, on its Elbe cruise from Berlin, will be the only passenger vessel with docking privileges in Prague.
Uniworld 800/733-7820. Besides traditional river cruises in France and Germany, Uniworld offers trips to less expected places. Time-travel up China's Yangtze River through the Three Gorges, past rice terraces still worked by barefoot farmers and oxen. Or board their newest cruise down Italy's Po River from the French Alps to the Adriatic sea. If you can't bear to go back to land yet, you can always hitch a ride on a passing ocean liner.