I had never set foot on a cruise ship nor had the slightest desire to do so until my granddaughters called one cold January day and asked if I would chaperon their dance team on a five-day cruise to Nassau in the Bahamas. They had been invited to be the entertainment for the last night of the cruise. Their dance lessons are projects I paid for, and have been involved with for many years. I have sat for many hours watching them rehearse and have been the backstage mother for countless Christmas shows and recitals. My granddaughters are 15 and 17 years old. Their glorious dancing years are almost over. How could I say no?

So I am going on a cruise. I don't like crowds. I don't like to sleep in strange beds. I'm bored with the Caribbean, but, after all, it is only for four nights and five days. I love my granddaughters and the girls on their team, and I know and admire their dance instructors. I knew I would be in good company. Another thing I have never done is go anywhere with a group of women, but these young women are dancers and athletes. I decided to open my mind and broaden my horizons.

Another thing I don't like to do is live on a boat. When I was younger, my husband and I kept a 50-foot sailboat in the British Virgin Islands. We would sail it around for weeks on end, usually in the company of our two best friends. I think of that experience as a dreary round of rationed water, canned food and begging to get off and spend a night at Little Dix Bay. The idea of being on a ship with a bed and showers is new to me. "You'll have to get a new bathing suit, Grandmother," the younger girl said to me. "And, of course, a base tan."

In April I ordered a bathing suit from Lands' End and began to lie out in the sun for 30 minutes every day. These preliminary activities changed my personality to such an extent that I was entertaining the idea of buying a flowered dress. I didn't actually buy one, but I tried several on and did buy a tropical print shirt from a 75-percent-off sales rack. In my normal life I do not wear flowered dresses, print shirts or anything with writing on it. Perhaps the sun was going to my head.

It was around this time that I called the cruise line and upgraded the reservations for myself and the girls. The team had special fares for the cruise, and I had told myself it would be an adventure to travel in steerage, but then thought better of it. "Give me adjoining cabins on the deck where you would book your parents," I told Michael, in the Miami office of Royal Caribbean. "Make sure I can sleep."

Chaperons are supposed to stay in the same room with their charges, but I trust my granddaughters not to get into trouble. Also, their sleep patterns are not in tune with mine. They would be getting up about the time I went to bed for a nap and would want to watch television after I was asleep for the night.

With my base tan, my print shirt and my upgraded reservations, I decided I was ready for whatever a cruise turned out to be. Stories of cruise ships limping back to port with all the passengers sick with dysentery did cross my mind, and I prepared myself for a certain amount of Disneyland tackiness, but I was ready. I used to scuba-dive when we had to fill our own tanks with air and mail the regulators to California to be checked for holes. I figured I could weather a five-day cruise.

The girls, Aurora and Ellen Walker, and I all met up in Cape Canaveral on the eve of the cruise. I made everyone go to bed early. Aurora had warned us that we might have to wait in lines to board the ship, and we wanted to be early to avoid the crush. Visions of Ellis Island. I do not stand in lines. There is nothing I want enough to stand in line to get.

I was amazed at the size of the ship. No photograph can prepare you for the size of a cruise ship. We weren't even on the largest one. Royal Caribbean has a class of ships called Voyager that are much larger.

Our voyage began on Sunday. There was no waiting in line. We arrived early, parked the car under a palm tree and were whisked aboard the ship by a polite, helpful crew.

Our cabins were spacious and well-appointed, and the interior was as clean as a hospital. I was breathing sighs of relief.

By noon we were in deck chairs in our bathing suits, putting on suntan lotion and drinking lemonade.

"Ellen Gilchrist," I heard a voice say. It was Donna Burke, the dance troupe's choreographer and leader. "They've put us in the lounge," Donna said. "I can't believe they did this to us."

Sovereign of the Seas has four dance venues. One is a beautifully designed theater with professional lighting and sound. The rest are dance floors in lounges. The British cruise director had reserved the theater for her own revues, in which she stars and which include professional dancers and stand-up comedy routines, replete with bathroom jokes and making fun of newlyweds.

Our dancers were relegated to a dance floor in a lounge.

"It's too small," Donna continued. "There are posts that will make entrances and exits impossible, no dressing rooms."

Donna's aide-de-camp, Kathy Gaye, joined us. "Donna will make it work," Kathy said. "When we were young, we danced on every sort of stage known to man. Donna will find a way."

"I don't know," Donna said. "I can't squeeze a chorus line in between those poles unless I rechoreograph the whole thing."

The three of us stood in a circle, thinking about this bad turn of luck. Then the dancers began appearing all around us in their bathing suits. I have known most of them since they were children and seen them through countless recitals, lost tap shoes, missing props and capes and hats, last-minute lighting and sound problems, and this year, the loss of the lead dancer to an injury during dress rehearsal. The show had always gone on, and it would again.

A band began playing calypso, the irresistible, seductive music of the islands. Lunch was being served, waiters danced by, carrying trays of exotic drinks. Our girls

began to dance all around us, first moving in their deck chairs, then standing up and mocking dance moves to amuse one another, then out onto the dance floor, showing off, being silly, having fun.

I started laughing. In a few hours we would set sail for the Bahamas. Carpe diem. Let the good times roll.

I am much too vain to be interested in food. I live on low-calorie, high-protein foods and like to eat the same things day after day. Oatmeal, salads, olive oil, broiled meats and tofu are the staples of my regular diet. I was so worried about not being able to stick to my regimen on the cruise that I had packed some Luna bars and sugarless bread in my cosmetics kit. I should not have worried. It was possible to eat almost exactly as I do at home. In a group of dancers, my culinary tastes were considered normal. Our Portuguese waiter put up with my ordering broiled salmon every night until the last night. On the last night she threw up her hands and begged me to let her bring me something with a sauce.

My main interest in the meals was in how our girls looked. Every night they turned up looking resplendent in their old prom and homecoming and cotillion tea dance dresses. I do not know how they fit all those clothes into their suitcases, except young girls' dress-up dresses are made of very thin materials now, as you may have noticed.

I had three sons. I lived in a world of baseball caps and football uniforms and athletic shoes. It is the great joy of my older years to watch my granddaughters dress up and put on makeup and jewelry. We are Southern women and think of dressing up as an art form.

Before dessert, which most of them did not eat, the girls went back to their rooms to change into clothes more useful for dancing. They went from one dance floor to the next, moving in groups of three or four, dancing to all the different sorts of music being played. They took shortcuts through the casino, where they found me twice putting quarters into slot machines. "I'm appalled that you found me gambling," I said. "This is a foolish, wasteful thing to do. No one ever made money in a casino. Forget you saw me here."

"It's all right," one of Ellen's friends told me. "My mother's been doing it, too."

On that first night I wandered around making sure everyone was safe, then went to my cabin and fell asleep. They were too big to fall off the ship; they were policing each other; the bars didn't sell drinks to minors; they were traveling in packs. And I don't like to stay up after 11 o'clock at night.

At dawn on Monday I was awakened by the sound of something dropping near the lifeboat outside my porthole. My years on a sailboat came back in an instant, and I was on my feet going to check the rigging. "Go back to bed," I told myself, but by then I had opened the curtains and seen the Atlantic Ocean, so I put on my running shoes and went to the promenade deck to watch the ship sail into morning.

There were still faint stars but light was beginning to show on the horizon. Early morning has always been my favorite time at sea. I have stood on the bow of a sailboat a thousand mornings, watching light return to the world.

The promenade deck had a walking path that circumnavigated the ship, and I began to walk around it, starting at my muster station and changing directions each time I passed it. There was a man in a deck chair reading a John le Carre spy novel and a woman sitting on a towel in Zen meditation, but aside from that I had the ship to myself. I walked several miles, then began to climb stairs to other decks and explore the ship. I found coffee and cookies near the lounge where we were scheduled to perform. I fixed coffee and walked around the stage looking at the problem. Donna was right. It was too small and the poles on the sides of the stage were in the way for entrances and exits. It was outrageous, but I was sure the cruise director would change her mind now that the girls were aboard and she could see how lovely they were.

I left the lounge and wandered around until I found the real theater. It was exactly what we needed.

I went up to the cafeteria and had breakfast, then returned to the promenade deck to watch the ship drop anchor near our first port of call, a tiny island called Coco Cay, which belongs to Royal Caribbean and is in the process of being developed. The island is very small, and the development is not very far along, but the waters surrounding it are the unforgettable turquoise blue that is one of the great joys of the Caribbean. I have had a lot of fun swimming, scuba-diving and snorkeling in that clear blue beauty, and it made me smile for my lost youth to see it now.

I went ashore on the second tender and was greeted by photographers. I posed in my white hat and proceeded to walk around the shopping stalls. There are brightly painted houses and huts with thatched roofs and not much to buy or see. I walked down to the beach bar where the waiters were playing calypso music and opening boxes of plastic cups. One of the waiters caught my eye and began to dance. I began to dance along. We giggled and moved out onto the dance floor. Sell it, I was thinking, forgetting I was the resident grandmother. Show them what you have.

We danced for half an hour. I did not live in the British Virgin Islands all those summers for nothing. I can dance to that music.

"You dance like a girl," the waiter told me when we parted.

"This week I am one," I answered and knew that it was true.

Around 11 I went back to the ship to see if Ellen and Aurora were awake. This became the pattern of the trip. They would stay up late and sleep all morning. I would get up early and wander around or go to the library to read the ship's newspaper. I would eat breakfast alone, take yoga classes or work out in the gym, talk to strangers, watch the ship dock or put down anchors, and in general have a lovely time living my insular, observer's life.

Around noon I would wake the girls, and they would get ready for their activities of sunbathing, rehearsing, dressing up and wandering around with their friends. Our dancers were in every activity and contest on the ship. They put on acts in the Karaoke Lounge, judged the Sexy Legs contest, took part in line dances and were constantly being photographed for the cruise video.

So the ship sailed on, as the poets say. I felt lucky and blessed to get to watch these young men and women enjoying their reward for a year of hard rehearsals after school and on Saturday and Sunday mornings. If we had to perform in a lounge, so be it.

My granddaughters' mother is the Yankee daughter of a NASA scientist. She has never understood what Ellen and Aurora and I are doing at Donna's School of Visual and Performing Arts, but she lets us do it nonetheless.

What I was doing on this trip was living vicariously. Sometimes that is as delicious as the real thing.

Our main destination was Nassau. I had gone there in 1958 on my honeymoon and remembered it as a gorgeous, dangerous place with revolution in the air. On that trip I wore green silk and a perfume called L'Air du Temps and walked on the beach at night carrying my high-heeled shoes. In the afternoons we wandered down the main street, which was full of elegant shops and open bars. There was music everywhere, and late at night in the cafes there would always be a moment when the music would change and they would play a song called "Island in the Sun," which was their revolutionary anthem. It is a haunting song, made famous in the United States by Harry Belafonte. I was looking forward to seeing how they had used their independence now that they had gained it. "Oh, island in the sun. Willed to me by my father's hand."

I got up early on Tuesday morning to watch them dock the ship in Nassau. They sailed the ship into the harbor, then turned it around and backed into the docking piers. It was amazing, like watching Gulliver being handled by the Lilliputians. Two blocks away was the city, looking lovely in the dawn. Farther down was the tall, yellow hotel where I had stayed in 1958. At that time it seemed to be far away from the heart of town. Now it was surrounded by buildings, but the beach was still there and I could imagine myself in my green silk strapless dress, high on gin martinis, wading in the surf to show off for my husband.

I dressed up for Nassau and was the first person off the ship when they put down the walkway. It was so early the shops weren't open yet, but I wanted to reconnoiter before I took the girls shopping.

There was not much there. The Nassau I remembered has disappeared. In its place is a dusty tourist town with jewelry stores and streets that need fixing. No matter how hard I tried, I could not find a single place that I remembered.

Still, I did not give up. I went back to the ship at 10 and woke the girls and begged them to go shopping with me. They sleepily agreed and we went to town.

"Great," I said. "We'll look for shoes."

We spent two hours shopping but could not find a thing to buy. The merchandise in the shops was covered with dust. We did find some nice jewelry shops, and we found a Versace outlet mall and had fun laughing at the outmoded clothes with thousand-dollar price tags, but in the end we gave up.

The action on Nassau has shifted to neighboring Paradise Island, which has a casino and an aquarium and lots of stalls for hair-braiding.

In the afternoon most of our group went to Paradise Island. Some of them stayed all day and missed the captain's dinner that night.

I did not go with them. I was so disappointed in Nassau I stayed on the ship and read and slept and had a massage and got my hair done in the beauty salon.

Maybe the magic is still in Nassau and I am the one who has lost it. Everyone else had a wonderful time there.

At midnight we began our long, slow voyage back to Florida. We moved through the ocean at 10 knots as the last two nights and last day of our journey went by. It would be a busy day for our group. We had to rehearse all afternoon and perform that night. Donna Burke was going into take-no-prisoners mode. While we had been enjoying the cruise, she had been planning how to fit chorus lines onto the dance floor and how to move the entrances and exits around the poles. The other chaperons and I went to work, haranguing the assistant cruise director to move tables and chairs out of the way and to hang lights in the makeshift dressing room.

The girls were as serious now as Donna was, checking and rechecking every piece of costume, helping each other with makeup, slipping into the dressing room without letting the audience see them, all the professional traits Donna has been teaching them all these years.

"Much has been accomplished," I say to myself when I get worried about my progeny and wonder if I have done enough to help them. There are some things I have done that I know were worthwhile. Surely Ellen's and Aurora's dance lessons are in that category.

This day was my reward. At 10 that night we took the stage and completely wowed a standing-room-only audience. The dancers did five numbers, including a piece in which Ellen and Aurora had starring roles. When the show was over, the troupe was given a standing ovation.

"Well, honey," a man sitting near me said to his teenage daughter, "I guess you might as well just quit those dance lessons you're taking in Pennsylvania. Compared to this that isn't even dancing."

The other chaperons and I turned and glowered at him, as was proper, but we couldn't help being pleased by the comparison.

I woke the last morning of the cruise and knew I had been made softer by the experience, kinder, less critical. I loved the silly cruise. I loved the multinational crew; the Indians, Bahamians, Englishmen, Portuguese, Norwegians, Italians. I had not gained an ounce and my fingernails had grown half an inch, proving once again that housework ruins manicures.

Disembarking was easy. By 10 we had stuffed our luggage into the trunk of my car and begun our 600-mile drive home. I was even looking forward to that. These years when I can have my granddaughters to myself are almost gone. I am too smart not to treasure them while I can.

As soon as we were on the highway, the girls went to sleep and slept most of the way. Is there anything a grandmother likes more than her granddaughters asleep beside her, completely exhausted from dancing the nights away?

Ellen Gilchrist's latest book is I, Rhoda Manning, Go Hunting With My Daddy & Other Stories, published by Little, Brown.