Every summer my son and I -- just the two of us -- take a vacation from school, work and strict rules. The theory is that playful downtime and shared memories will get us through the inevitable squabbles over homework, flossing and dirty socks. Last winter, I started noticing all those high-energy commercials from the cruise industry featuring attractive families having the multi-generational time of their lives. I'd never been on a cruise before -- never even tempted -- but this year, I needed a trip that straddled that fine line between adult relaxation and kid fun: My eighth-grader turned 13, which officially made me the mother of a wisecracking, precocious, hard-to-impress teenager.

As I watched the ads, somewhere deep in my brain a voice whispered, "You could read and play blackjack. Carter could have the run of the ship. Both of you could swim with dolphins. Quick, sign up while he's still willing to be seen in public with you."

So I signed us up for a seven-night Caribbean cruise in late August. If I was going to splurge, I wanted one we could both love. Carter had outgrown Disney, and therefore its ships, but wasn't quite old enough for a stately, sedate crossing. A spin on cruise critic Web sites convinced me that I needed a big ship full of amenities. My search quickly narrowed to Royal Caribbean's massive Voyager ships, which boast rock-climbing walls, basketball courts, mini-golf, arcades, ice-skating rinks and swimming pools with hot tubs. What clinched the deal was the elaborate Adventure Ocean program for children, which includes separate activities for teenagers 12 to 14 and 15 to 17, as well as a teens-only disco, lounge sundeck and Internet center.

I thought it was a safe setting for Carter to test his wings. I imagined my son, under the semi-watchful eye of a counselor, racing through the ship with a passel of giggling adolescents, and then I thought, "Yikes! He's going to be too busy for mom-son Kodak moments!" When I broached the idea of a cruise, I stipulated that he had to eat dinner and go on shore excursions with me.

Love at First Bite

Navigator of the Seas, a 138,000-ton, 15-deck mammoth that holds 3,000 passengers and a crew of 1,200, is a small city with more than 13,000 square feet dedicated solely to teenagers -- about a quarter of Deck 12. I was comfortable letting my kid wander the ship by himself, but wondered how we would find each other for meals and excursions. My travel agent suggested bringing walkie-talkies, but a ship representative told her a limited number were available free on a first-come, first-served basis from Guest Relations.

As it turned out, the free walkie-talkies had been discontinued. I declined to purchase a $50 pair from the ship store, and we decided to wing it on our first night on the ship: Carter went to the arcade and a Teen Mix & Mingle, I headed for the casino and Promenade, a three-story shopping mall that serves as a floating Main Street. We planned to meet up in two hours, but he missed the teen welcome and sensibly headed back to the cabin. His crazy mother wandered the decks for an hour hunting for him before it occurred to check the room. "We've got to come up with a better system," I muttered seconds before we both sank into a long, deep sleep. The next morning we devised a note-in-the-cabin method of keeping tabs, which we used exactly once before finding a noteless rhythm of designated meeting times and places.

Within 24 hours, we had settled into our temporary home. Our cabin was a small but comfortable interior room overlooking the Promenade. Hurricane Katrina was headed west, away from our scheduled path out of Miami, and the weather was sunny and warm.

Each day we received Cruise Compass, a comprehensive listing of the day's schedule and activities, and a separate roster of activities for the Navigators (ages 12 to 14). As with most cruises, most food and entertainment were included in the price, and we had plenty of options.

Our week-long cruise included two days at sea and four in Eastern Caribbean ports. By day, we lived in swimsuits or shorts. Nights were more complicated. As a rookie cruiser, I had tried to guess what passes for casual, "smart casual" and formal for a teenager. Renting a tuxedo struck me as excessive, and I decided dress pants, shirt and tie would suffice for him. I threw a couple of cocktail dresses in my bag, but correctly figured they wouldn't throw us overboard if I guessed wrong. Truth is, the definition of "formal" is broad, to say the least.

That first night, we bypassed the formal dining room and beelined for Johnny Rockets, an old-fashioned diner where we inhaled burgers, onion rings and chocolate malts. Carter fell in love with the place at first bite and declared it a perfect 10. "Mom, I can't find anything wrong with it," he said, shaking his head. "It's kind of disheartening, because I like to think I'm a tough critic. But it's perfect." But moms cannot live on burgers alone (not to mention the $3.95-per-person surcharge), so on our second night I dragged him -- tie and all -- to the soaring three-story dining room. We were escorted to a table in a side room, next to a waiter's station, where we were cheerfully served lots of mediocre food.

I asked for and promptly received a seating change, and we lucked out with a table in the main room and two delightful families with boys near Carter's age. But the dining room food never got a 10 from my teen critic, or from me. God knows there was plenty of it, and serving 1,500 people at once rarely lends itself to gourmet moments.

Ditto for breakfast and lunch buffets in the Windjammer Cafe. Then again, there were cookies and pizza 24 hours a day from the Promenade Cafe, and a $28 drink card bought Carter unlimited sodas from anywhere on the ship, which is all a kid really needs on vacation.

On the plus side, the staff was relentlessly friendly, engaged and helpful, from the captain to the janitors. Most passengers save up all year to take this vacation, and the crew is trained to make them feel like royalty. For the first time in his life, Carter was treated with respect by every adult he encountered, who carefully inquired what he'd like to eat, drink and do. He was spoiled and fussed over, and kid enough to be amused when our cabin attendant created folded towels into the now-famous animal shapes.

If I have to choose between so-so food and a lovely staff or perfect food with indifferent service, I'll pick the towel animal guys any day of the week. At the end of the trip, I happily tipped the recommended amounts, and a bit extra.

Teen Beat

The programs for children ages 11 and younger are carefully monitored and structured, but kids 12 and older are allowed to come and go or participate as they please. Although I encouraged Carter to attend a number of the Navigators' scheduled activities, he quickly concluded that most of the daily programs never actually took place. (The line cancels activities if not enough kids show up.)

There were plenty of teenagers on this cruise, and plenty in the Living Room and the Fuel nightclub, the teen-only lounge and disco, but they preferred to simply hang out or watch movies, and the counselors never insisted on participation. For some teenagers this would be heaven, but it bored Carter. I nudged him to try and try again: Surely the poker session would be well attended. We arranged to meet by the pool in an hour. He was back in 10 minutes. "Told ya," he said with a grin. "Didn't happen."

I knew we had entered new territory when my video-game obsessive passed on a scheduled PlayStation session. "You don't want to play PS2?" I asked, shocked. "Nah," he said. "There's too much to do."

If anything, we found an abundance of shipboard treats well-suited for a modern teen. The arcade was well-equipped and lively, although Carter spent just $40 there during the entire week (room keys double as shipboard charge cards). The rock-climbing wall had no allure for him, but he played free mini-golf every day, twice when he could lure me up for a match I would usually lose. The ship's closed-circuit television offered ESPN, sitcoms and stupid movies, which he adored and I ignored.

What surprised and pleased me, however, was that Carter had a blast at the live game shows. I feared the "adult recommended" meant they would be too mature for him, but aside from a midnight comic restricted to adults, most of the after-dinner offerings were less risque than the average PG-13 movie. He loved "Battle of the Sexes," "Love & Marriage," "Quest" and "Majority Rules" -- and yes, the sight of a dozen men racing around in bras was profoundly silly and right up his alley. He was delighted by Cruise Director Graham Seymour, a playful Englishman in the Monty Python tradition. He stayed up past midnight almost every night, and then collapsed in a contented slumber.

What he loved best of all was bingo, which he stumbled upon for the first time while exploring the ship on Day Two of the trip. Restricted from the casino for another five years, my little poker player discovered elaborate variations on B-I-N-G-O. For a mere $35 per session, my son (accompanied by an adult -- me) could play five games for the big jackpot, which grew to more than $7,000 by the end of the cruise. Did we play bingo almost every day? Yes. Did we spend $175? Indeed we did. Did we win a single game? No, but we came within one number -- and Carter received a T-shirt after playing the fourth time. Did we have a ridiculously good time together? Yes.

Given the scope of shipboard offerings, I never felt pressured to cram too much into our shore excursions. I could book them through Royal Caribbean, but was told that it was just as easy -- and often cheaper -- to arrange them in port. I dug around on the Internet, trying to figure out the best trips in San Juan, St. Thomas, St. Maarten and Nassau. I wanted to spend most of the time with Carter, so I ignored the heavy-handed shopping pitches (okay, I bought one pair of earrings), anything too exhausting or the dreaded "too educational."

In San Juan, we skipped the ship's $30-per-person tour to the Bacardi Rum factory and opted for the local ferry (50 cents each way) and a gypsy cab ($2 each way) to the factory, where I received free samples and Carter learned a little history and science. Feeling festive, we even posed for touristy pictures with macaws on our heads. In St. Thomas, a local driver took us to Magens Bay for a lazy, sunburnt afternoon on the beach. In Nassau, we hopped a water taxi to Paradise Island, where we walked around the fabulous Atlantis resort and spent an hour gazing at the massive lobby aquarium.

The biggest splurge ($159 per person) was the only excursion I booked in advance through the ship: an up-close and personal encounter with dolphins on Anguilla. After ferry and bus rides, we landed at a small facility where we split into small groups, strapped on life jackets and bobbed in an oceanside pool with Al, our designated dolphin. For about 30 minutes, Carter petted, kissed and fell in love with the playful creature, laughing at and with him.

"Can we sneak in with the next group?" he pleaded, only half-kidding.

"I think they might notice," I answered.

Instead, we ate lunch near the water's edge and watched Al & Co. leap and dive while I casually taught my son about the fight to save wild dolphins from fishing nets. Sneaking in a little education, served with sun and a souvenir DVD, couldn't be all bad.

Last Splash

Carter didn't want the cruise to end, and neither did I -- I slept late every morning, read novels cover to cover, and drank the best martini of my life. We were headed back to a new year of school, to homework, to the sad aftermath of Katrina. To bedtimes and vegetables.

On our last night on the ship, we headed for the pools and hot tubs to watch our final Caribbean sunset. With all our racing around, we had somehow managed to do everything but swim in the pool, and I splashed around just a bit before settling into the hot tub.

I wasn't there 10 minutes when a dozen fresh-faced teenagers piled in next to me. Most were just a year or two older than Carter, but light years ahead in the dating game. They flirted back and forth in English and Spanish, clearly delighted to be exactly where they were, doing exactly what they were doing. I looked around -- not one of their parents in sight, as far as I could tell.

"So, this is my future," I thought with a sigh.

Okay, then. On our next cruise, I'll just have to bring a couple more books. But he still has to join me for dinner.

Roxanne Roberts is a staff writer in The Post's Style section.

| INSIDE | For anti-cruisers, a ship that trawls Alaska's Inside Passage. Page 5 | Wondering what to do at ports

of call? Check our Caribbean-Port-O-Matic for recommended eats and activities at five top stopovers. Page 6 | Active endeavors on the Royal Caribbean's Navigator of the Seas, clockwise from top: the on-deck basketball court; Johnny Rockets 1950s- style diner; the author's son Carter dances with a dolphin during a shore excursion; and Carter tees off on the ship's miniature golf course.