ABOARD L'ABEILLE SUPPORTER -- The tender vessel is bound for the spot where the Titanic sank on April 15, 1912. It carries aboard, from the little French island of St. Pierre just south of Newfoundland, a half-dozen of the entrepreneurs who make up the U.S. end of the expedition devoted to lifting from the floor of the ocean, down 2 1/2 miles from the surface, artifacts and memorabilia from the Titanic.

There is the tension one might expect in returning to the business of diving deep into the ocean, deeper by far than any submarine can travel. There is additional tension because although all the tradition of salvage adamantly affirms that the operation could proceed with the kind of self-assurance one associates with the salvage operations that in years gone by have unearthed gold and diamonds and frankincense and myrrh off Bermuda, Florida, Peru, indeed everywhere in the world where storms or pirates have sunk boats loaded down with treasure -- despite all this, there is something different about the Titanic.

Although it has been 75 years since it went down and there are now only a half-dozen survivors of the haunted night, the Titanic is widely thought of as an international monument, incorruptible in its chaotic arrangements on the ocean floor. For this reason great tenderness is being shown toward the White Star's glamorous, ill-starred vessel. There has been no manhandling of the ghostly carapace, the forward end of it separated from the stern end by a half-mile.

During the preceding six weeks, divers in the tiny submersible with its prehensile arms and marsupial front have brought up only loose-lying artifacts that would otherwise continue to rest on the ocean floor. Where these will finally end it is too early to know. There is pressure from French museums (France has been the principal partner of the U.S. enterprise). And the U.S. situation is complicated by a bill of Sen. Lowell Weicker forbidding any memorabilia from the Titanic from being brought into the United States with an eye to ''profit.'' This presumably means that if the Metropolitan Museum in New York were to judge artifacts from the Titanic as being of historical interest, even as artifacts from the Argonaut are seductive to human curiosity, it could not legally bid to possess them.

The problem is one part legal, one part moral, and the adventurers-entrepreneurs on this 200-foot tender led by Robert Chappaz of France and John Joslyn of California are not finally resolved on what to do with it all, after it goes from here to France, where a government agency will preside over the restoration. And then to Monte Carlo or Paris, where the artifacts will be a part of a documentary scheduled to be shown in America on Oct. 28.

The hold the Titanic has on the public is evidenced by the score of books that have been published since the 700-odd survivors came into New York harbor on April 18, leaving behind them at 40-16 north latitude, 40-14 west longitude, more than 1,500 people who died on that starlit night, when the ocean was so smooth that if its temperature (4 degrees below freezing) had served to create ice, passengers who did not get a place in the lifeboats could have skated away.

But the waters south of Newfoundland do not freeze into ice, however efficient they are in freezing people who jump into them. Jump into them not as trainees for the Polar Club but because some passengers elected that alternative to merely going down with the giant 882-foot vessel, the largest ever built at the time, embarked on its luxurious maiden voyage from Southampton to New York.

One popular legend about the Titanic is that those who were not aboard the sparse lifeboats went down to the bottom of the sea in the vessel. They didn't. In fact, the evidence is that, as they crowded the stern deck, waiting for the final, exhausted plunge as the sea water, pulling in through the starboard cavity sprung by the iceberg, crawled aft toward them, they had on life preservers. They were visible to the survivors in the 20 lifeboats and rafts. When the Titanic went down, its crew and passengers floated up under the buoyant imperative of their life preservers, including the musicians who were playing in the main saloon as the great ship went down.

One hopes there were wise men among them who thought to ditch their life preservers, because that way they'd have died within a matter of minutes. As it happened, they floated up from the descending ship in a tight circle around the spot where the ship had squatted from the moment the engines were turned off at a quarter before midnight, until 20 minutes after 2 in the morning, when it took its final, all but vertical dive. Instead of going down, they floated in the freezing water, and there was much testimony by the survivors to the awful wails of pain, desperation and entreaty, lasting as much as 40 minutes, as little by little the cold froze them to death; leaving forever unanswered the question: Why didn't the lifeboats, half of which were half-empty, make any effort to rescue at least a few of the survivors? There will be no hint given of why this was so when I go down to see the remains of the Titanic.