Strenuous efforts by advocates for the handicapped have blown away a lot of the fog about whether cruise ships merely accept wheelchairs or actively provide access for them.

The 1991 edition of an annual chart published by Cruise Lines International Association, an industry trade group, shows that virtually all of 95 listed vessels accept wheelchair passengers.But, these advocates point out, interpreting this to mean that the ship is accessible could be the start of a nightmare: on many ships, wheelchair users would have to be lifted over doorsills and carried into bathrooms.

And even ships that advertise accessible cabins may accommodate only wheelchairs 22 inches wide or less; the average wheelchair for a 150-pound man is 28 inches wide.

Dr. Michael Quigley, an advocate for the disabled, testified in Congress this spring that only 130 of 43,600 cabins on 100 cruise ships that visit the United States were truly accessible to wheelchair users. This works out to less than one-third of 1 percent.

But there has been some progress; this is an increase from spring of 1989, when Tom Gilbert, another advocate, put the total at 93.

Both Quigley and Gilbert have checked vessels themselves. One travel agent checked a new ship and found the lifeboat deck unreachable by wheelchair.

Quigley, an epidemiologist who uses a wheelchair, has bullied ship lines, consulted with their executives on solutions and pressed his case in any forum he could find.

Gilbert, also a wheelchair user, has been a travel agent and now runs the Organization for the Promotion of Access and Travel for the Handicapped in Tampa, Fla.

Consumer pressure has yielded results.

Rich Steck, a spokesman for Royal Caribbean Cruises, said that the line's Viking Serenade, which now has one cabin for the disabled among its 487, will have four when she emerges from refitting in the spring of 1991.

The Nordic Empress, which entered service this May, has 4 out of 805. The line's giant new Sovereign of the Seas, with its total of 1,142 cabins, has not a single one for the disabled.

But Steck said two new vessels being built in France, the Monarch of the Seas and the Majesty of the Seas, would each have four cabins out of 1,177. Picking a cruise ship is treacherous because of the vague terms used in brochures and charts.

People who use wheelchairs should call a specialized travel agent for booking cruises, even if they do not ordinarily use an agent. Helen Hecker, a nurse in Vancouver, Wash., publishes an annual comb-bound directory of travel agents who specialize in serving the disabled, arranged by state and noting specialties. It costs $19.95, plus $2 for shipping: Twin Peaks Press, Box 129, Vancouver, Wash. 98666; 800-637-2256.

Betty Hoffman of Evergreen Travel in Lynnwood, Wash., is probably the best-known specialist, having been at it since 1961.

Mrs. Hoffman does not take any cruise line's word for accessibility, but checks herself or asks her son and partner, Jack, or Dr. Quigley or Gilbert to look.

Princess Cruises, in her estimation, understands the extent of the demand for accessiblity not just of cabins, but of public areas and outside decks, and getting on and off the ship itself. And she said that Royal Cruise Line "is catching on."

Hoffman said Holland America is outstanding in providing doorways that are wide. In the Hoffmans' estimation, overall these lines do the most for the disabled.

Pincess Cruises has nine ships with 4,588 cabins; three of the ships have a total of 26 cabins for the disabled. Royal Cruise Line's two ships have 763 cabins, with four cabins for the disabled on one ship.

According to Hoffman, Cunard's 58 cabins for the disabled, with a 22-inch clearance in the bathroom, are better suited for those who can walk. Evergreen Travel is at 4114 198th Street, S.W., Lynnwood, Wash. 98036; 800-435-2288.

Here is a summary of information on 143 cabins, gleaned from 13 lines on the Gilbert or Quigley lists.

Admiral Cruises converted one suite on its Emerald Seas for use by the disabled. The price is in category 4 on a scale from 1 down to 11.

Chandris Celebrity Cruises has two specially fitted inside cabins on its Meridian, and four outside on the Horizon, which went into service in May. The cost for the Meridian is in category 9 on a scale of 1 down to 14. On the same scale, the Horizon cabins' category is 5.

Albert C. Wallack, a senior vice president for Celebrity, said that ramps in the public areas of the Horizon had an impact on sales. "This is a benefit not only to those in wheelchairs but those who walk with a cane or who have difficulty with stairs," he said.

Commodore Cruise Line has one cabin for the disabled, a standard inside double, on its Caribe I. The price is in category 7 on a scale that ranges from 1 down to 12.

Crystal Cruises has four cabins on its Crystal Harmony, two of them on the penthouse deck, which are in the A category on a scale from A down to K. The others are in the E range.

Cunard-NAC has three vessels with special cabins. The Queen Elizabeth 2 has two, both single cabins in the first-class category, which cost above the middle level.

The Sagafjord has 12 fitted cabins, the doubles with prices in the C, D, H and J categories on a scale that ranges from AA down to A through J, the singles in the B and C categories on a scale of A to E. The Vistafjord holds the record with 44 cabins for the disabled out of 368. They are in all but the top category.

Holland America, now owned by Carnival Cruises, put four cabins for the disabled on each of three vessels while they were in drydock in the last year and a half.

On the Nieuw Amsterdam and the Noordam, the four are on the outside and in price range C on a scale from A to O. On the Westerdam, which returned to service in March, the cabins are in categories D, E and G on a scale that starts with a suite then runs from A to P.

Norwegian Cruise Line has 14 cabins on two vessels: 4 on the Seaward and 10 on the Norway. All but one of the cabins are in the middle price range; the other, an inside on the pool deck of the Norway, is in category 9 on a scale from 1 down to 12.

Premier Cruise Lines, which sells cruises with Disney World packages, has adapted one cabin on its Star-Ship Oceanic. The rest of the vessel, according to Laurel Thompson, a spokeswoman, has always had portable ramps with limited accessibility for the disabled. The cabin is priced in category 4 on a scale of 8 down to 1.

Princess Cruises has 3 ships with a total of 26 cabins for the disabled: the Sky Princess has 6; the new Crown Princess has 10 and the Star Princess 10. The cabins are doubles, both inside and outside, and the prices are in the middle range, according to Julie Benson, a spokeswoman. The Regal Princess, due next year, will have 10.

Royal Caribbean's Nordic Empress has two of its special cabins on the outside and two on the inside, both on the A deck. The inside cabins are in the M price category and the outside ones in the J category on a scale that runs from A down to Q.

Royal Cruise Line has four cabins on its Crown Odyssey. The prices are in the middle range, with 10 categories below and 7 above.

Since last year, according to Mimi Weisband, the ship has installed permanent ramps to the outdoor decks, which were urgent in the event of emergency, and also now has portable ramps to go over ledges in other parts of the ship.

Royal Viking Line has four special cabins on the Royal Viking Sun: outside doubles in the midprice range.

Seabourn Cruise Line has two new all-suite vessels, the Seabourn Pride, 1988, and the Seabourn Spirit, 1989, each with 4 suites out of 100 for the disabled.

However, the bathrooms of the Seabourn's special suites do require some mobility in the legs for entry and thus cannot be used by paraplegics. John Farnworth, a spokesman, said the suites for the disabled sell very well, with three of the four usually taken on a given voyage.

All the suites on a vessel are priced the same, he said, possibly $500 a person a day in the Caribbean and $600 a person a day in the Mediterranean, with two in a suite.

A new law to assist the handicapped, signed by President Bush in July, apparently will require American cruise ships to take steps to accommodate wheelchair users and other disabled travelers.

However, federal officials, who are just beginning to set standards of compliance, have not decided whether a foreign-registry ship "has to comply," said Dennis Cannon, accessibility specialist, U.S. Architectural and Transportation Barriers Compliance Board.

And yet, he said, American tour companies may be required to book on ships that accommodate the handicapped.