Don't get us wrong: A transatlantic crossing aboard ship can be an experience of a lifetime, a luxurious pause between the rush of here and the dash of there, and abundant proof that getting there can be half the fun. Just watch out if:

The water in your drinking glass starts jiggling in the wrong direction.

Somebody mentions that you're heading into a "depression," and you know they're not talking about your mental health.

The ship's doctor starts offering his expensive seasick shots for nothing.

Whether you're experiencing the ambiance of a luxury cruise ship or "roughing it" on a freighter, expect the unexpected. At least that's what we learned during our two transatlantic crossings. As it happened, we traveled both times on a big cruise ship. But the ensuing surprises, we're convinced, could have taken place on any sort of voyage.

In a crossing, unlike a cruise, you are either building strength for the rigors of travel or recuperating from same -- by reading, swimming, jogging around the deck, dancing, drinking and, of course, eating. For who knows where the next meal will come from when you are deposited in the wilds of France, Belgium or even England? Coming home, you may face even worse -- the interesting growths inside your neglected refrigerator.

As a result, your dining table becomes a focal point of ship life. On our crossings, not only was the food excellent, but the waiters were fun, like something out of Monty Python. They were also our communications link to the inner workings of the ship, something we'd find important later on.

Our table, set up for six, was meant for four. No matter: We six got along famously, and by the third day were discussing our progress in mastering the big ship's nooks and crannies. At dinner that night we noticed the ship seemed to be changing direction, a phenomenon confirmed by the swing of the water in our water glasses, which was perceptibly changing direction, too.

"What gives?" we asked our waiters, for the loudspeakers that had been full of calls for various events and shop openings were now silent.

"Man overboard," the waiters replied and, when pressed, supplied more details: The ship was turning around to search for a man who was missing and presumed overboard. This was late October in the North Atlantic, and the man couldn't have lasted 15 minutes in the water: He had been missing since he went for a walk on deck four hours before, according to his wife. We were more likely to spot an iceberg than this poor soul.

Maritime law requires a four-hour search, our waiters replied loftily.

About midnight, we felt another change in direction. A couple came into the ship's nightclub (where the "young set" -- anyone under 55 -- gathered to dance to '60s, '70s and '80s rock) and said the captain had announced we were turning around again and would try to make up the time.

There was no mention in the ship's newsletter, a daily compilation of news, ads and information, about the man overboard. Our only proof we didn't dream it all -- including Scotland Yard's men helicoptering out to the ship to interview people -- was an item in one of the London papers.

Later, one of our table mates, a delightful lady in her eighties (who liked ships so much she was sailing to England, spending 36 hours and then going back home), strongly doubted we would make up the lost time. She noted that most ships don't have much flexibility in their schedules.

Sipping her manhattan, she said, "They go full speed ahead and rely on their stabilizers, regardless of the weather."

We were to remember her word later.

The ship did make up most of the time, though we were still late arriving in England. But our train to London was waiting and off we went, well fed, danced, gambled and entertained to a T.

After a week of fun in London, we reboarded the ship for our return crossing. We didn't have the same cabin, but we had asked for and gotten the table manned by our favorite waiter-newscaster-comedians. They informed us gleefully that we were heading into two "depressions."

Depression, we were to learn, was shipboard language for "storm," a word never articulated.

By midmorning the lecturer on creative writing was having a hard time getting her words out. We were glad we had taken a precautionary Dramamine and enjoyed both cocktail and lunch, and met one of our table mates.

The ship announced a schedule for seasickness shots and encouraged them. They were expensive, but worth it: Apparently they knocked you out for a few hours and then you were fine for the rest of the trip.

We met our other table mate briefly at dinner -- he had two bites of a roll before he rose, excused himself, said he would return shortly, and didn't. The other man never showed.

The dining room was decimated.

"This isn't anything," Martha said, remembering her days as a Navy brat on military transports. "You don't have to worry until they wet the tablecloths to keep things from flying off."

Usually the after-dinner entertainments were SRO by the time we finished eating, but that night we had good seats for watching a pair of dancers until they cut short their performance when one of them began to get seasick.

Lulled by our large meal and the rolling of the ship, we went to bed early and were soon asleep. But at about 5 a.m. the telephone bounced off the nightstand and into Bill's face. Papers and books were sliding all around and before long we were, too, especially as we tried to secure the cabin contents.

The ship was really rolling now. Doors were slamming, the soap and toothpaste plunged into the wash basin, and a box of Kleenex sailed across the bathroom. We tried to read while listening to the noise of the ship and then, suddenly, its silence. "Good Lord, they've turned off the motors!" Bill said. (Later we learned it was the motorized stabilizers that were cut off because they weren't working.) After a long wait for the call to abandon ship, we finally fell asleep.

At 8:30 a.m. we were awakened by the captain's voice over the loudspeaker, apologizing profusely for the "inconveniences" passengers might have suffered during the night. The ship was now sailing south, he told us, to avoid the worst(!). We should be entering smoother waters before too long, he said, but our arrival in New York would be delayed.

The dining room opened late for breakfast, and Martha noticed immediately that the tablecloths were wet. But it had been too late. Our waiters, who gloried in bad news, informed us that smashed china and glass had been everywhere that morning -- and there were salt and sugar all over the floor.

Exploring further, we found perfume bottles and china littering the floors of the shops. The casino was wrecked, the one-arm bandits fallen on their faces, the roulette tables overturned. (It would remain closed for most of the rest of the trip, saving us all money.) Mirrors in the bar had been smashed, and the carpeting was stained and wet.

Those of us who were up and around took advantage of the lack of crowds. We snagged two screens in the usually mobbed computer-learning center, watched a movie in the best seats and generally enjoyed the feeling of spaciousness.

By this time the famous seasick shot was being given free. While we waited for the return of our table mates, we asked our waiters more questions. "Lucky the thing's still afloat," one said darkly before they both happily launched into a description of a recent crossing's misfortunes when the ship had run into a full-fledged hurricane.

There was no mention of our "depression" in the ship newsletter, of course, but plenty of talk among the passengers, especially as the seas abated and people once again felt equal to active discussion. Our favorite story, even if apocryphal, concerned the couple whose marriage had long ago turned sour. The storm threw her into his bed, and now they were having a second honeymoon.

Eventually, our table companions returned -- a lively young Australian and a somewhat mysterious, albeit friendly, American who talked away without revealing much about himself. (We decided he was CIA.)

They said they had had their fill of ships, but we felt differently. Where else can you get away from your usual routine while eating and sleeping well, having a cocktail in a choice of a half-dozen cozy bars, dancing disco, ballroom or rock, swimming, exercising or learning computers or bridge from relaxed experts? Besides, there was the adventure: Flying telephones! The spray across the bow!

We'll be back. Bill and Martha Grigg are free-lance writers. THINGS TO KNOW BEFORE YOU GO

Know your ship. Find a travel agent who knows your ship and can tell you what part of it is the quietest before you select your cabin. A cabin on a lower, less expensive deck may actually be more comfortable: The lower you go, the less motion.

A large ship can be confusing to find your way around. Read up before you go -- and spend your first hours exploring it from stem to stern.

Beware the maiden voyage. A maiden voyage -- whether on a new ship or a revamped one -- is a shakedown cruise and one you can afford to miss.

Prevent seasickness. Transatlantic crossings, particularly in the "off" seasons, are going to feature "interesting" weather. (On the other hand, you pay less in these off-season months.) If it's your first trip, regardless of weather, take Dramamine, Bonine or another nonprescription anti-motion sickness drug before you get aboard and then ease off. A prescription for the anti-seasickness "patch" worn near the ear is also popular. (Some people are sensitive to the drug used in the patch, so check it ahead of time.)

Realize nothing's perfect. Getting on and off the ship will not be the fun part of your trip. Expect confusion and lines.

Relax. You have almost a week with nothing you have to do. You don't even have to get off the ship to see something you're supposed to, as on a cruise. (If you feel guilty about this, most ships will give you a tour of the bridge and galley.)

Enjoy. Enjoy the experiences you don't get on land very often. How many times do you have a chance to dance to a live orchestra, let alone experience live entertainment -- and with no cover charge! You can learn to play bridge, do needlework, dance the rumba -- or just walk around the decks. -- Bill and Martha Grigg