The luxury liner RMS Titanic, which the history books say sank in 1912 after a collision with an iceberg tore a 300-foot gash in its side, showed no such gash to explorers who recently completed 11 days of diving in a small submarine to examine the rusty wreck.

"We saw absolutely no evidence of a gash," expedition leader Robert D. Ballard of the Woods Hole Oceanographic Institution said yesterday at a news conference here.

Ballard, who examined most of the 882-foot Titanic's hull from the small research submarine, said that many of the steel plates in the region of the hull where the gash was supposed to be -- the forward end of the starboard side -- had buckled, popped their rivets and separated from adjacent plates.

"It appears the damage was really separating the plates," Ballard said. The amount of separation would have caused more than enough leakage to sink the supposedly unsinkable ship, he said.

Ballard said, however, that it was impossible to see the foremost part of the lower hull because it is buried 50 feet in mud. He said, however, that he felt confident in ruling out the gash theory because he was able to examine most of the area where the gash was supposed to be and because rescued passengers reported feeling no sudden collision.

It was because of these reports that analysts concluded the ship had suffered not so much a crushing blow as a slicing by a sharp wedge of ice.

Ballard speculated that the ship simply ground against the massive iceberg.

Between the time the accident occurred, at 11:40 p.m. on April 14, 1912, and the time the Titanic went under 2 1/2 hours later, 705 people escaped in lifeboats. More than 1,500 died.

The Woods Hole team found the wreck last September and photographed it from an unmanned platform lowered from a research ship. That expedition established that the Titanic had broken into two main pieces, both of which rest virtually upright on a nearly featureless muddy bottom 2 1/2 miles below the surface. The site, near the edge of the continental shelf, is about 400 miles southeast of Newfoundland.

Although last year's exploration produced hundreds of detailed photographs showing clearly identifiable parts of the Titanic and even wine bottles and silver plates scattered on the floor of the Atlantic, Ballard and his crew returned to the wreck this month for a personal exploration. Inside their small submarine, the Alvin, Ballard and two crew members roamed over and around the wreck for a total of 33 hours in 11 dives.

After a 2 1/2-hour drop to the Titanic, the Alvin could explore for three hours before the 2 1/2-hour return trip to the mother ship on the surface.

The chief purpose of the revisit was to test a new, remote-controlled video camera called Jason Jr. The camera is a prototype of a device the Navy is developing under contract to Ballard's Deep Submergence Laboratory at Woods Hole, Mass.

While the Alvin rested on the Titanic's deck, technicians sent the 28-inch-long Jason Jr., a "swimming eyeball" that carries its own lights and maneuvering motors, off to enter hatches and prowl the ship's interior. A 200-foot-long cable relayed Jason's view to a screen in front of the controllers in the Alvin.

Although the expedition came back with hours of videotape and 57,000 still photographs, none shows the wreck as a whole. Because there is no sunlight at the bottom and artificial lights illuminate only a few feet ahead, the search was frustrating, Ballard said.

"It's like being in a sequoia forest at night with a flashlight and you say, 'It's great bark,' " Ballard said.

Wide roaming, however, established that the ship broke in two before it settled to the bottom, the stern section landing some 660 yards from the bow. The sections rotated as they fell, landing with both pointed ends aiming in about the same direction.

Ballard said it was not clear whether the ship broke up at the surface or on the way down. Calculations show that at about 1,000 feet of depth, some of the ship's chambers may have imploded, allowing the ship to break apart. The bottom is about 13,000 feet down.

Although the bow section was relatively intact -- it underwent some bending upon hitting bottom -- the stern was a scene of "sheer carnage," Ballard said, adding that "it looked violent and destructive." He said it was an emotional experience to explore the stern section because that is where most of the dead had been. He said the wreckage of the stern was too damaged to permit safe exploration.

Ballard said that when the main sections hit bottom, they blasted out craters still visible. Between them much rubble, including quantities of coal, the ship's fuel, could be seen. One of the engine's boilers had landed away from the main wreckage and a coffee cup had settled onto it.

Although Ballard released several photographs yesterday, none showed the cup or other more poignant finds that he claimed, such as a patent-leather shoe, and "the only thing that looked human," a china doll's head. Ballard, who is keeping the best photos to sell, has become controversial for what some see as unseemly self-promotion and commercial exploitation of work done, at least partly, at taxpayers' expense.

The shoe was one of the few traces of organic material remaining on the Titanic. The wooden wheelhouse, for example, was completely eaten away by wood-boring worms, as was much of the ornate wood carving that once decorated the ship's elegant staterooms, lounges and dining rooms. Even the wooden deck, which in last year's photos looked intact, was found to have disappeared.

All the steel portions of the ship were encrusted with rust, some of which had sloughed off, forming what Ballard called rustsicles.

Although it would have been easy to retrieve small objects from the wreck, Ballard said he decided against it. "We felt it was better to leave them where they were," he said. CAPTION: Picture 1, Remotely controlled, the "swimming eyeball" called Jason Jr. leaves a submersible to take close-up pictures of the Titanic. PHOTOS (c) WOODS HOLE OCEANOGRAPHIC INSTITUTION;Picture 2, Jason Jr. spots ship's ribbing, railing and a porthole whose brass still shines. PHOTOS (c) 1986 WOODS OCEANOGRAPHIC INSTITUTION; Picture 3, Bollards used to secure mooring lines from a pier to the luxury liner were located on the starboard side of the wreck. PHOTOS (c) 1986 WOODS HOLE OCEANOGRAPHIC INSTITUTION; Picture 4, The towed camera sled Angus illuminates a cargo crane in the stern, which had broken away from Titanic's main hull. PHOTOS (c) 1986WOODS HOLE OCEANOGRAPHIC INSTITUTION; Picture 5, A third of a mile south of the bow, a copper kettle from Titanic's galley rests in debris. Ocean currents keep it polished. PHOTOS (c) 1986 WOODS HOLE OCEANGRAPHIC INSTITUTION; Picture 6, Carrying crew of three, the Alvin surfaces near its mother ship. Each dive took 2 1/2 hours to descend, 2 1/2 hours to rise. BY WOODS HOLEOCEANOGRAPHIC INSTITUTION. -- THE WASHINGTON POST; Picture 7,Illustration, no caption, BY JOHNSTONE QUINAN -- THE WASHINGTON POST