Grandparents at Sea With Children : Growing numbers bring the grandkids aboard as special programs and discounts make traveling together easy, amusing and economical.

Jeanne McCareins’ friends thought she was crazy when she told them she planned to take her teen-age grandson on an Alaskan cruise. He’d be bored traveling just with her, they warned.

Fourteen-year-old Justin McCareins’ buddies weren’t any more enthusiastic. “They thought it was weird that my grandma was taking just me,” said Justin, who lives in Itasca, Ill., and received the trip as an eighth-grade graduation gift.

“But they were all absolutely wrong,” said McCareins, a realtor in her 50s from suburban Chicago who previously had taken Justin’s older brother on the same cruise.

“It was probably the best trip I ever had,” agreed Justin, who didn’t want it to end. His brother can’t wait to go again.

“You get kind of jaded as you grow older,” added McCareins. “Everything was so exciting for Justin that it made it much more exciting for me. I’d encourage any grandparent to do it.”

Growing numbers of doting grandparents are opting to do just that, cruising with their grandchildren to places such as Alaska, the Caribbean, Hawaii and other exotic locales. Verna Brown, a retired administrative assistant recently returned home to Maryland after a cruise around the Hawaiian Islands with her husband, a retired fire captain, and two teen-age grandchildren. “They were hoping for a hurricane so we couldn’t come home,” she said.

“My grandparents really know how to party,” added her appreciative granddaughter, Heather Lindsay.

Some grandparents take the kids when parents are too busy to get away, delighted for the opportunity to spend time alone with their grandchildren.

Many other grandparents opt to take the entire family. With their children spread out across the country, it may be the only time all year everyone is together.

Whatever the motivation, grandparents say cruising is an ideal vacation to take with grandchildren because it is so easy--no packing and unpacking at different hotels, no restaurants to find, no activities to plan.

“Kids used to get a piece of jewelry for graduation from their grandparents, now they get a cruise,” joked a Norwegian Cruise Line official.

Maybe that’s because cruising has never been more child-friendly or affordable. This fall, one cruise line is trying to outdo the next with special programs and discounts aimed at the family market. Many are ideal for grandparents.

Royal Caribbean is offering selected free sailings for the third and fourth people sharing a cabin with two regular-fare-paying customers. American Hawaii Cruises and the Delta Queen Steamboat Company are touting programs in which the child cruises free with two paying adults.

Premier may have the best deal of all: Kids accompanied by two adults may cruise on the Big Red Boat and go to Disney World for as little as $99--including air fare--from selected gateway cities including Chicago and Newark ($199 from Los Angeles).

This winter, the new American Family Cruises--its first trips are scheduled for December--will offer some sailings where kids travel free and others where their fare is just $95, plus air fare.

The vast majority of cruises are booked through travel agents. Check with yours to see what packages might be available when you want to sail and be sure to check whether children’s activities are offered on those dates.

Two travel agencies specializing in the grandparent-grandchild market are planning to add cruising to their itineraries. The Maryland-based Grandtravel agency will offer a Scandinavian cruise (800-247-7651) and the Chicago-based Generations an Alaskan trip (312-404-2400).

A small full-service Los Angeles travel agency also is getting into the act: Omnicruises hopes to organize grandparent-grandchild-only groups to go to Alaska next June (213-463-4630).

Cruising with grandchildren is not always easygoing, however. It’s essential to plan a cruise with an expert who understands your family’s specific needs. Just ask Californian Brenda Ingram about her American Hawaii Cruise. Sailing with a 9-month-old grandchild proved to be a nightmare. Initially, there wasn’t even a high chair on board. “I wouldn’t do it again with such a young child,” she said, adding that her two older grandchildren had a ball.

One Los Angeles-based cruise specialist has created a Family Cruise Club division to serve this market exclusively. It now annually books nearly 1,000 families from around the country, offering discounts on selected sailings, providing kids’ travel kits, publishing a family cruise newsletter and giving away $50 gift certificates toward a first cruise. (For a free copy of “The Parent’s Guide to Family Cruising,” call 800-242-9000.)

Justin McCareins, meanwhile, has his own advice for the grandkids before they set sail. “Be tolerant of older people,” he advises. “And remember, even though they’re old, you can have fun.”