The Star Princess entered service at the end of March, sailing from Florida to the western Caribbean on a 10-day cruise, with 10 cabins out of 735 adapted for wheelchair users.

That may not look like a big number, but it ranks among the larger totals for a single vessel.And it was enough to register a big jump in the number of accessible cabins for people with no mobility, for there is a big difference between "wheelchairs accepted," a common locution used by cruise lines, and "wheelchair accessible."

Here is one example. Often vessels will put in ramps to go over the high sill, or lip, at the entry to a cabin. When asked, though, cruise lines acknowledge that the ramp will not help a wheelchair user get into a raised cabin bathroom, use the toilet or reach the washbowl.

When a cruise brochure says "wheelchairs accepted," the line may expect a wheelchair user to travel down the corridor to a fully accessible public bathroom.

Accessiblity of cabin bathrooms accounts almost entirely for the difference between a ship that simply accepts wheelchair users and one that can accommodate those without any mobility.

Unless the passenger gets specific information about bathrooms, disappointment is likely.

The advent of the 10 accessible cabins on the Star Princess, the newest vessel of Princess Cruises, was a source of satisfaction to Tom Gilbert of Tampa, a wheelchair user working to persuade the cruise industry to create more accessible cabins and be frank in representations to travel agents.

The cruise industry boasts that cruising is the perfect vacation for wheelchair users, who number 6.5 million in the United States.

In light of this, Gilbert, who recently formed the Organization for the Promotion of Access and Travel for the Handicapped, said the group wants more candor about accessibility.

Gilbert said, for example, that a chart given to travel agents by the Cruise Lines International Association, which has 34 member lines, vastly overstated the number of ships with truly accessible cabins.

Gilbert's concern is that the designated cabins be accessible to quadraplegics, triplegics and paraplegics with no mobility. Someone with limited mobility - say, a paraplegic who can stand with a walker and maneuver into a shower - may be comfortable in a conventional cabin equipped with a sill, he said.

His research, based on cruises, inspections of ships in port and his analysis of cabin specifications, has led him to conclude that of the 116 vessels calling at U.S. ports, 11 contain cabins that are fully adapted for wheelchair users. These ships, Star Princess included, have 93 cabins adapted for wheelchair users.

The CLIA chart lists 86 vessels that the owners say accept wheelchair passengers.

Read closely, the chart shows that almost half of those vessels report high sills on their cabin doors and do not say that ramps are available.

Advocates for wheelchair users are pressing for greater accessibility either built into the designs of new ships or installed at the next refitting.

Travel agents who specialize in cruises say the fully accessible cabins sell out quickly.

In fact, according to Yvonne Nau of Ask Mr. Foster About Travel in Northridge, Calif., the single wheelchair-accessible cabin on the Stardancer of Admiral Cruises, which sails out of Los Angeles, is the first cabin booked on all sailings and has a waiting list of about a year.

Thus some lines - Princes, Admiral, Norwegian Cruise Line, Cunard and Holland America - are making an effort to provide at least a few accessible cabins.

Others, notably Carnival Cruise Lines, concede that none of their cabins qualify, at least not technically.

In Norwegian Cruise Line literature, the gap between "accept" and "accessible" is clear.

In an entry under "physical disability," the line discusses its regular cabins candidly: "Please note that there is a five- to six-inch riser to bathroom in cabin; bathroom doors are 20 to 22 inches wide."

Stacy Morgan, a spokeswoman, said that adapted cabin doorways were 281/2 to 291/2 inches wide and adapted bathroom doorways were 271/2 to 281/2 inches wide.

Gilbert said that he had inspected the Seaward, which can carry 1,534 passengers, and that there were four cabins equipped for the wheelchair user. These are in price category 7 on a scale of 1 to 13, with 13 high.

Louise Weiss, author of "Access to the World" (Henry Holt, paper, $12.95), cruised on the Seaward last month and said that officials told her that these cabins, which were part of the ship's original complement of cabins, were always occupied.

On the Norway, with a capacity of 1,800 passengers, Gilbert reported that eight cabins had been adapted for wheelchair users in price category 5 on a scale of 1 to 12.

Gilbert said that he had also verified the accessibility of cabins on each of two Admiral vessels, the Emerald Seas and the Stardancer, and the one aboard the Caribe I of Commodore Cruses.

According to Richard Skinner, a spokesman for Holland America, which has been acquired by Carnival, three Holland America vessels will each get four fully accessible cabins when they next go into drydock: the Niew Amsterdam this spring, the Noordam in late fall, the Westerdam when she is stretched in the winter.

The Rotterdam, built in 1959, is too old to be changed, he said.

In her "Access to the World," Ms. Weiss includes a simple chart giving details on 37 ships. This includes notations on which public facilities are inaccessible and on the widths of doors.

Cunard Line said that two cabins on the Queen Elizabeth 2, 12 on the Sagafjord and 44 on the Vistafjord are fully accessible.

Princess Cruises, in addition to 10 cabins on the Star Princess, has six for wheelchair users on the Sky Princess.

"With the growing number of handicapped people who want to travel," said Nancy Loewenherz, a spokeswoman, "we have found it necessary to meet the demand."

These cabins are in price category D on a scale of AA down to M.

Royal Cruise Line's Crown Odyssey, launched in 1988, was built with four wheelchair cabins aboard.

The Organization for the Promotion of Access and Travel for the Handicapped and Gilbert may be reached at Box 15777, Tampa, Fla. 33684.

To receive a list of vessels and cabin numbers accessible to wheelchair users, enclose a stamped, addressed return envelope.