At Slickers restaurant and bar in Rehoboth Beach, Del., five customers sat scattered on the restaurant's plush banquettes celebrating the Fourth of July. Manager Donald Foraker surveyed his desolate room. "This time last year, it was jammed," he lamented.

At the Brookside Campground outside Virginia's Shenandoah National Park, owner Lloyd Wakeman stared gloomily at an empty stretch of asphalt. "Not even one camper," he said, shaking his head. "Year before last on July Fourth, we had 40 parked here."

Ed Scofield didn't even have to visit his motorboat rental business on Deep Creek Lake in Western Maryland yesterday to know what he would find: 13 of 15 motorboats bobbing empty on the wave. "Normally, you couldn't even get a reservation [for one] if you waited till the Fourth," he sighed.

From Atlantic beaches to Pennsylvania battlefields to Virginia national parks, an informal Washington Post survey showed Fourth of July tourist business was noticeably down compared to last year -- sometimes by as much as 50 percent.

Virtually all who were interviewed agreed that the primary reason for the lack of tourists was not overcase skies or the rain that dampened much of the region, but the gasoline shortage or as many businessmen insisted, the imagined gasoline shortage.

"For july Fourth, this is unbelievable, absolutely unbelievable," said Ruth Detwiler, executive director of Gettysburg's Chamber of Commerce, as she spoke of the teeming tourist trade the nation's birthday usually brings to this historic town.

The economic threat is prompting businessmen and communities to fight back. The owner of a spanking new hotel in Rehoboth Beach, for instance, chopped $11 from his room rates in a desperate gamble to lure tourists. The Gettysburg Chamber of Commerce has leased a service station to make sure there will always be a place for tourists to buy gasoline.

In Virginia Beach, Va., city officials are mounting a $50,000 media blitz to drive home their point that the resort is but "One Tank Away."

Yet, despite efforts such as those, the gasoline crunch seems to be winning.

"It's a man-made disaster is what it is," said Walter Brett, owner of Rehoboth Beach's newest hotel, the Commodore, where more than half the rooms were empty Saturday. "As far as I'm concerned, it's worse than a hurricane," Brett said as he talked of what he saw as a disastrous business situation.

In Gettysburg, for instance, in spite of the almost guaranteed gasoline for tourists, the big Howard Johnson's Motor Lodge -- usually booked solid between June and Labor Day -- was loss than half full. And the smaller Home Sweet Home Motel needed only one of the five maids it normally employs in the summer.

The problems are spilling over into organized tours there, too according to officials. Yesterday, bus tours to the famous Gettysbury Battlefield were running 50 percent below capacity.

In the Deep Creek Lake resort area a motel owner and a boat marina operator, who said they would normally be busy turning tourists away on the Fourth, instead were together grousing about business worries.

"I got people here right now crying real tears, business is that bad," said motel owner Del Carpenter, who had plenty of vacancies yesterday.

In Ocean City, Md., where the tourist trade is a $3 million-a-weekend business, officials estimated that a maximum of 175,000 visitors turned out of yesterday's holiday -- more than 30 percent less than last year's crowd.

"I'd rate it about the same as any other day this time of year. This is no holiday as far as business is concerned," said Chamber of Commerce executive director Gary Fisher.

Yesterday's disappointing weather and tourist turnout only augmented the crunch some businessmen already have been feeling this summer. Hale Harrison, co-owner of a group that runs four Ocean City hotels, said occupancy rates were down 15 percent last weekend. And the Beach Plaza Hotel on the boardwalk suffered 18 cancellations late weekend, ones that spokesman Paul Wall blamed specifically on the gasoline problem.

Fisher said a poll of the Chamber's board of directors showed seven members indicating business levels were the same or better than last year and three reporting a decrease.

Ocean City is one of those communities that are fighting back. The city has launched an advertising campaign to let the public know gas is available there and that, just in case, the city has purchased a special supply of "insurance" gas and stored it at an abandoned service station.

However, the beach resort, 153 miles from Washington, is not the only spa finding novel ways to beat the gasoline crunch.

The major of Wildwood, N.J., an island resort at the southern tip of the state, sent a desperate mailgram to 60 newspapers and radio and television stations yesterday.

"Yes, Wildwood, N.J., has gas . . . No one seems to believe us mostly because of the news media. We have gas. It's the truth," the mailgram, signed by Major Guy Muziani, read.

In an interview, Muziani said that business is down possibly as much as 40 percent compared to last summer, but that gas in his town is plentiful.

That was the word, too, from many of the other resort areas -- Maryland's Eastern Shore, Nags Head, N.C., Skyline Drive in Virginia, and Harpers Ferry, W. Va.

In one extreme case, Lloyd Wakeman who owns a gas station in Luray, Va., west of Skyline Drive, reported that he had more gasoline than he could sell.

Wakeman said he lost part of his June gas allocation "because my [storage] tanks were too full" at the end of the month.

Sometimes the gasoline reports of the tourist officials conflicted with those of the motorists who made the long drive to their resorts.

In Colonial Williamsburg, 158 miles from Washington, a spokesman said that 26 of the 33 gas stations in the area reported they would be open at some point on the fourth. But George Bitett, who drove all the way from Hollywood, Fla., said he searched for an hour yesterday before finding a place to feed his fuel-starved car.

Almost every resort area, from North Carolina to Pennsylvania, from West Virginia to Delaware, reported a deluge of long distance calls about the gas situation.

Businessmen at a few resorts said those phone calls were the only impact they had felt from the fuel crunch.

At the posh Homestead, in Hot Springs, Va., where the least expensive rooms rent for $73 a day with meals, the manager reported that business was actually up in June compared to the same month last year.

"We cater to conventions, and we haven't lost any," said Clifford Nelson. "Besides, we do own and operate a gas station and we give our guests preferential treatment."

At the sprawling Kings Dominion amusement park north of Richmond, officials said there was "a softening of business" but no heavy impact from the gasoline crunch.

While most tourists may be staying home, those few who are venturing out are proving to be an especially hardy breed.

Elaine Rathfon, making a July Fourth tour of Gettysburg yesterday, reported that she and her family, of State College. Pa., "walked for a week back home so we'd be sure to have enough gas in the can to get here and back today. CAPTION: Picture 1, Ocean City beaches are normally packed on July 4, but the resort was uncrowded yesterday. By Margaret Thomas -- The Washington Post; Picture 2, "among vacationers who made it to Ocean City for the Fourth were these truck troups camped north of city. By Margaret Thomas -- The Washington Post