In the face of legal action by the Steamship Authority, Ralph Packer has finally agreed to stop the unlicensed transport of rental cars to Martha’s Vineyard on his barges for the summer tourist trade.

The two shipping operations have been in dispute over the rental car trade for several years, but under a stipulated restraining order presented by both sides last Friday in Dukes County Superior Court, sitting in Edgartown, Mr. Packer’s company was prohibited from carrying rental cars or other vehicles between the Island and the mainland, without first securing a license with the SSA.

An exception to the prohibition on carrying vehicles was made for “cranes and other large construction equipment that cannot reasonably be carried on the Authority’s vessels because of their size” and for trucks carrying modular homes, bulk and containerized cargo as carried in the past.

The order does not necessarily end the dispute. It preliminarily enjoins Mr. Packer’s company, Tisbury Towing and Transportation Co. Inc., while negotiations continue between the sides. If no agreement is reached, the matter could still come to trial.

Friday’s hearing was over in only a matter of minutes. The SSA was represented by Edgartown attorney and former Vineyard boat line governor Ronald H. Rappaport and Mr. Packer was represented by Norman A. Peloquin 2nd, from Providence, R.I. The parties agreed to terms shortly before they were to appear.

Later, Mr. Packer said the agreement does not mean he now accepts that the Steamship Authority’s enabling act gives it a monopoly on moving cars to the Island. But he acknowledged the preliminary injunction had put a stop to his deal with Hertz car rentals, at least for now.

“We’re in kind of a holding pattern until we can determine the direction everybody’s going in,” he said.

SSA general counsel Steven M. Sayers welcomed the agreement and said the boat line now hoped the parties could come to an agreement on licensing Mr. Packer’s operation on a long-term basis.

“Rather than go to the trouble of having the judge issue something that neither party may have wanted, we decided it was better to be in control of our own fate and for both parties to agree to a stipulated order,” he said, adding:

“The best thing that can happen, in our opinion, for the authority and Mr. Packer and the public, is that all of us redouble our efforts to come to an agreement on licensing on a long-term basis.”

At the heart of the dispute is a difference in interpretation of the provisions of the 1973 Enabling Act which sought to prevent private operators from creaming off the lucrative summer trade, and leaving the SSA to cover the unprofitable off-season, to the ultimate cost of year-round residents.

If the boat line goes into the red, Islanders can be levied to make up the loss. The last such assessment happened in 1962.

The act gave a legislated monopoly to the SSA for the movement of people, vehicles and freight to and from the Vineyard and Nantucket, unless other carriers were licensed by the SSA.

But Mr. Packer’s company was in operation long before the act came into being. It began bringing petroleum to the Island in 1930, and certain of its activities, he argues, are therefore grandfathered, meaning they are exempt from the act.

The SSA argues they are not grandfathered, although it has been content to allow Mr. Packer’s operation to continue its long-standing business of moving fuel and bulk freight. It would like to have those operations licensed, though, without any license fees.

The business of moving rental cars, however, began much more recently.

Mr. Packer argues that his deal with Hertz, which began almost six years ago, arose because the SSA could not meet Hertz’s requirements for moving a large number of vehicles at one time.

“They wanted to move a large number of cars to the Vineyard, without drivers,” Mr. Packer said. But the SSA insisted each car must have a driver to move it on and off their ferry at each end of the journey.

“We were able to accommodate that,” he said, adding:

“It’s a volume move that Hertz wishes to do and they’re extremely well organized. They wanted cars here just before Memorial Day and just before Fourth of July, and then back off Island just after Labor Day.”

The SSA first demanded in October 2003 that Mr. Packer stop carrying the cars. But repeated complaints were ignored.

In January 2008, boat line general manager Wayne Lamson expressed his frustration at the monthly meeting of SSA governors.

“I see the vehicles going over on a barge and then I write a letter and then I see the cars coming back,” Mr. Lamson said.

“We have previously sat down to talk about this, and it is clear he is not going to change his ideas on what he can do . . . and he doesn’t seem to think he has to get a license,” he said, and warned that any further shipments would bring legal action. Then came the summer, and it happened again.

Last October Mr. Rappaport filed a complaint in Dukes County Superior Court, seeking to stop the traffic, as well as to recover damages for the past activity.

There was to have been a hearing then, but Mr. Packer preempted matters by agreeing not to move any more cars, while the parties looked for a solution.

Two days before Christmas, the matter went back to court for a status conference — essentially a progress report. There was little progress to report.

Another status conference was scheduled for February, and then, when no agreement had been reached, a hearing date was set. Which is what happened on Friday.

Until this week’s sudden agreement, Mr. Packer had remained calmly defiant.

“Hey,” he told the Gazette in January, “we’re here just doing our thing.”

Both sides have said throughout that they want to avoid a trial.