There's a buliding boom on the high seas.

About 23 new cruise ships will be launched over the next three years. They're bigger and fancier than ever and will add about 40,000 berths to the 111,000 available this year.The new ships have luxurious passenger suites (some bigger than a condo with two bedrooms, two bathrooms and a private verandah), lavish art collections, high-tech fitness centers and glitzy entertainment - from Broadway-style shows to virtual-reality games.

There's even shipboard miniture golf. The Legend of the Seas, a ritzy Royal Caribbean ship launched in May, has an 18-hole miniature golf course on one of its outside decks, complete with little trees, sand traps and water hazards (besides the ocean). No long drives though: the longest hole is 32 feet.

More down-to-earth services aboard new ships include a 24-hour pizzeria on Carnival Cruise Lines' ship Imagination.

As the new ships enter the market, some older ships will be shifted away from the Caribbean - the world's biggest cruise market - to European or other itineraries. But the glut of ships is bringing some deals for cruise customers.

Excess capacity

"Excess capacity" is the buzzword in the cruise industry, meaning there will be more berths than passengers to fill them as new ships flood the market. That's bringing discounts as cruise lines compete for bookings - and as they face a decline in passengers, a rarity in the steadily growing cruise business of recent years.

Passenger numbers were down to 4.45 million last year from 4.48 million in 1993, said the Cruise Lines International Association, and down another 4 1/2 percent for the first quarter of this year. Cheaper warm-weather vacations in Mexico (thanks to the devalued peso) and strong competition from Las Vegas, Disney World and other land-based vacations were among the reasons for the drop.

But cruise lines still are trying to avoid giving last-minute discounts to fill their ships. In recent years, most cruise lines have offered their biggest discounts for reservations made months in advance (the earlier they can fill up their ships, the happier the cruise lines are financially).

"The best discounts for next swummer's Alaska cruises end about mid-February," said Vicki Bowen, general manager of the Cruise Specialists travel agency in Seattle. "For European cruises for 1996, some of the early discounts have already ended."

Although early-booking gives the best choice of cabins and dates to passengers, not everyone can plan so far ahead.

"There are so many ships in the Caribbean and the ships are larger now, with 1,500 to 1,800 people per vessel," said Lynne Garfi the cruise coordinator for Doug Fox travel agencies in Puget Sound. "So there are a lot of `soft' sailings where cruise lines find that two to three months prior to sailing that they still need to fill half of the ship - so some are substantially discounting the prices."

Some cruise lines have been advertising week-long Caribbean cruises for $500 to $600 per person (for the most basic cabin, excluding air fare and port fees, and with restrictions on dates).

A few major ports in the Eastern Caribbean were damaged by recent hurricanes (see item below). But cruise ships haven't had to cancel sailings - just reroute some ships to different Caribbean ports.

Best fares

If you're considering a cruise, here are some ways to find the best fare.

- As always, shop around. Travel agencies are the best bet for comparison shopping for a cruise, but make sure you deal with an agent who knows about cruising.

- If you choose an early-booking discount, make sure your travel agent will monitor price changes and get you the cheaper fare if it's reduced after you've booked. Keep an eye on cruise-line ads, too.

- Don't expect real deals on the brand new ships: They're in high demand from curious veteran and first-time cruisers. Look to the older ships for better discounts.

- Avoid Christmas and other peak periods. Ships are heavily booked then, and there's little need for the cruise lines to discount.

- If you've cruised before, many cruise lines offer discounts to their "alumni."

- Go with a crowd: A group of family or friends with a minimum number of passengers, usually 15, can get a free fare for the 16th person (or spread the savings among everyone).

- Other discounts to watch for: family or child discounts in a four-person cabin; 2-for-1 fares; and air-fare discounts as part of a cruise package. And when you're pricing a cruise, be sure to ask what the port charges are: those fees, levied by each port, can exceed $100 on a weeklong Caribbean cruise.

- Be aware that shipboard expenses - alcohol, gambling, the hair salon, shore excursions and so on - can add up to several hundred dollars a person.

- One of the easiest ways to save on a cruise is to opt for the most basic cabin - an inside cabin on the lowest deck. But be sure that you really are one of those cruise passengers who only wants a place to sleep and shower.

Hurricanes

It's been rough sailing for some cruise lines this year, with two recent hurricanes in the Eastern Carribbean damaging some major ports. Earlier, there was a string of ship groundings and other accidents.

Last month, Hurricane Marilyn pounded the island of St. Thomas, in the U.S. Virgin Islands. Cruise ships have been rerouted from St. Thomas, where the capital city of Charlotte Amalie is usually one of the busiest cruise ports in the Carribbean with up to a dozen ships docking there on peak days. Ships also were routed away from the islands of Antigua and St. Martin/St. Maarten which were damaged in an earlier hurricane.

Some cruise ships are expected back at St. Thomas by the end of this month, said Virgin Islands spokesman John Newman. But many cruise lines have shifted their port calls to St. Croix, another of the U.S. Virgin Islands, and will stick with it this season. The number of cruise ships expected there in the peak winter season has swelled from 80 to more than 300, said Newman.

The hurricanes put a damper on some Caribbean-cruise bookings, said Lynne Garfi, the cruise coordinator for Doug Fox travel agencies in Puget Sound.

"Some people who were considering a first cruise, who were sitting on the fence, have chosen land vacations," said Garfi. "But those who have cruised before, who are experienced travelers, it hasn't stopped them."

Before the Caribbean hurricanes, the cruise industry suffered a string of accidents that industry analysts say also hurt this year's cruise business. There were no fatalities and the cruise lines offered substantial compensation (including free cruises), but the negative publicity hurt.

Among the accidents:

A Princess Cruises ship hit a rock near Juneau, Alaska, in June and the damage forced the cancellation of seven cruises. A fire aboard a Carnival ship disabled the liner on a Bahamas cruise in June. A Royal Majesty cruise ship ran aground on the Massachusetts coast in July. And salmonella poisoning affected several hundred passengers aboard a Celebrity Cruises ship in July.

Accommodations

Private verandahs are all the rage in new cruise ships - and not just for the luxury suites. Aboard Princess Cruises' Sun Princess, a 1,950-passenger ship being launched in December, many of the standard outside cabins have their own balconies.

"Once you've had a cabin with a private balcony, you never want to cruise without one," said Vicki Bowen of Seattle's Cruise Specialists. "It's a private space, where you can watch the ports and watch the scenery. We have a client who uses a wheelchair and it's perfect for her. She likes to be outside - and the balcony makes it easy."

Who takes a cruise? Retired people and rich people, is the traditional view.

But cruise lines are trying to lure the baby-boomers and more diverse customers. Themed cruises are aimed at every segment of the market, with cruises specialized for singles, gays, families, country-music lovers, and outdoors types. And even a theme cruise for nudists.

Still, cruise passengers are not a young or low-income crowd. The average income is $60,000 a year and the average age is 49, according to CLIA. More than 70 percent travel with their spouse. And of those with families, 17 percent take their kids.

Around the world

Have lots of time . . . and lots of money? What about a round-the-world cruise? It's yours on several upscale cruise lines for about $18,000 a person and up (although you could easily spend double that).

Or how about cruising on a freighter? Just you, and 10 or 11 other passengers, and a ship full of cargo. Freighter cruises often last for four weeks with fares starting at about $4,000 per person (although some shorter cruises are available).

Freighter cruises are a tiny niche of the amrket, so many travel agencies have little information. A good source is Freighter World Cruises, a Pasadena, Calif., travel agency and publisher of the "Freighter Space Advisory' newsletter: phone (818) 449-3106. A less comprehensive "Freighter Cruise Newsletter" is published by Maris, phone (800) 996-2747. TravLtips, a New York-based travel club, also books freighter cruises for members: phone (800) 872-8584.

Another source of information is the monthly newsletter "Freighter Travel News," published by the Freighter Travel Club of America, 3524 Harts Lake Rd., Roy, WA 98580.