To cruise or not to cruise is frequently not the question. More to the point may be "Can you get a cabin when you want it?" Then there's "Can you afford it?"

"You can't just say 'Okay, I'll go,' and then right away take off," protested a friend who considers herself a connoisseur of cruising. Well, maybe you can't but I did.

I signed up barely a week ahead in late January for the Sunward II out of Miami. In the sweepstakes for Last Person Onto the Ship, though, I came in second. The hands-down winner had to be Cathy, a Key Biscayner who came along to see someone off, looked around and decided to come along.

Both my friend and I could nonetheless be considered in tune with the times, my friend a bit behind. Late bookings are getting to be the rule rather than the exception, quite a change from the big-money days of two and three years ago, when some sailings were reportedly sold out a year or more ahead.

I didn't ask but I presume the Sunward II partly endeared itself to Cathy in the same way it had to me. Instead of setting sail for 180 days around the world, or even two weeks and 10 ports, our voyage was one of the increasingly appealing quickie cruises. We were headed for a three-night trip to the Bahamas and back. If you've cleverly calculated that cruising currently averages out to roughly $150 a day, the attraction of, say, $450 voyage over a $2,000 one is obvious.

Furthermore, some lines make things interesting by offering air-sea discount package plans and air-sealand plans (pre-or post-cruise hotel stays included), which may make a lot of sense when you don't live around the corner.

But there are also a few other variations on polite dealing. For example, when I balked at the quoted rate of $600 for single accommodation in a double-berth cabin, the Sunward's daddy, Norwegian caribbean Lines, offered me a "guaranteed rate" of $360. The guarantee meant that instead of my selecting a cabin, they could assign me one when I boarded and I would pay only the minimum $360 single -- even if what they had left turned out to be the presidential suite.

Actually Sunward II cabins are not vastly different from each other so that although the Gamblers' Special offer warmed what is sometimes known as my heart, it wasn't the biggest break in the world.

Of course, the point that quickie cruises are more possible for more people has hardly been lost on the shiplines. Right now the Dolphin, Emerald Seas, Flavia, Sunward II and Amerikanis do regular three- and four-night sailings from Miami, and, starting a few months ago, the Azure Seas from Los Angeles. There is also a four-night cruise out of New York aboard the Veendam, and three- and four-nighter ships in the Greek Islands. And there's talk of other short sailings as ships are refitted to take larger passenger loads and cruising continues its switch from class business to mass business.

In which case, what do you lose and what do you gain? I'd say I gained an increased appreciation for the need to shop around. And I experienced alarm over travel agents who had little information or inclination to communicate to me what they did know.

In other words, I wanted travel agents to ask me what I was looking for in a quickie cruise and have some answers to my question "What do the ones I'm considering -- the Dolphin, Emerald Seas, Flavia and Sunward II -- individually offer?"

I found assessments in short supply, though, so when, on the second day of our trip, all four ships were parked side by side in Nassau, I went exploring. Naturally I wasted no time in coming to some personal conclusions. For sure, if gambling was my obvsession, I'd head straight for the Emerald Seas. Never mind that the medium and upper bracket cabins also happen to be sizable and handsome in a traditional, superliner sort of way. The space allowed the casino makes it evident that this is a players' ship.

The Flavia, by comparison to the others, looked like a poor relation. However, the passengers I spoke with had good works for the food (Italian) and the crew (also Italian). My impression was that for a single woman, the Flavia just might have a few things to recommend it. After all, it has good wine at $5 a bottle, so there's one thing right there.

The Dolphin has a sophisticated appearance and a French connection. I still can't figure out what about it that put me off, but had the same feeling you get on a package tour when the guides don't struggle too hard to suppress their boredom. Although physically of good size, the layout of the cabins and the public rooms made me feel a little more closed in than I liked. Still, I wouldn't turn up my nose should we meet one day.

For me, the Sunward II was the ship that pressed the right buttons. I particularly liked (1) my cabin's sunshine colors; (2) the whole ship's quality of housekeeping and lack of litter; (3) a program that instead of settling us only in Nassau offered as well a beach party on a tiny, private, plamfringed Bahamian island; (4) drink prices of $1 to $1.60, things like French cognac included; (5) the unobtrusiveness of the casino, which has only slots and electronic roulette -- reportedly because Norwegian law allows only gambling against machines, not people; (6) some very slick, high-quality entertainment, apart from the otherwise-nice cruise director, who really should stick to singing in the shower; and (7) the Crow's Nest.

The last was a full-windowed lounge that was one of the best spots I've ever seen on any cruise ship for water-lovers to sit in comfort and at the same time actually see the sea, watch the sun set and maybe slip into Fantasyland, imagining yourself the gracious owner of all this, magnanimously sharing it with 700 or 800 of your closet friends.

But the sunny skies also had clouds: The Crow's Nest is frequently closed for private parties given by various group passengers.

As for food service, although it's available 24 hours a day, in the morning you can get only continental breakfast in your stateroom. The dining room menu is THE menu, no special orders allowed. The wine list is pricey (okay, I understand -- but don't expect me to like it).

Food in general was what a snippy friend of mine would call "adequate," meaning okay for convention crowds but light years from haute cuisine. Service, too, was casual, though wholly amiable.

About the same could be said of the passengers. We seemed to include much of the wrap and woof of life: a sprinkling of cowboys, one in lizard boots; several vacationing waiters; and advertising executive; an accountant-comptroller; whites and blacks; Coloradans, Californians and Carolinians; English, French and Spanish speakers; children, under-30s, over-30s, over 60s. They were a blend of singles, couples and families, with a large group of convention types. And whatever else you may have heard about quickie cruises, this was decidedly low-key.

A number of women took the occasion to dress for dinner in cocktail wear or long gowns all three nights, although, according to the pruser, the captain's cocktail party on the first night out is the only "formal" occasion. For men, that meant jackets were requested. However, the only real rule was no shorts at dinner.

Of course, the captain's party was followed by a gala diner, which was followed by a gala show, which was followed by a gala midnight buffet, which was followed by a gala-evening at the late-opening disco. If you survived that set of galas, you could count on not a trickle but a roaring stream of others. (On our night in Nassau, though, there was no show, possibly because the Sunward II management has noticed that passengers deset en masse and head for the nearby Paradise Island casinos. A few even resort to sleazy bars whose names are pried out of the Bahamian millionaires who work part-time as taxi-drivers.)

We noticed cruisers nonetheless prepared for the gaps between galas. In my case, that meant bringing along two books, some unasnwered letters and a box of Christmas cards intended either as late 1980 or early 1981, I hadn't decided which.

Well, don't rush to your mailboxes, correspondents. Daytime hours on the Sunward were filled with the usual shipboard offerings, from morning exercise classes to deck games, horse races, movies and the like. If you take in even half of a quickie cruise's activities, still have time to repack your belongings and walk off the ship with no help, I think that's all anyone should expect of you.