Massachusetts ? The discovery of two large pieces of the Titanic’s hull on the ocean floor indicates that the fabled luxury liner sank faster than previously thought, researchers said Monday.

The hull pieces were a crucial part of the ship’s structure and make up a bottom section of the vessel that was missing when the wreck was first located in 1985, the researchers said.

After the bottom section of the hull broke free, the bow and stern split, said Roger Long, a naval architect in Falmouth who analyzed the find. The stern, which was still buoyant and filled with survivors, likely plunged toward the ocean floor about five minutes later.

Previous researchers believed the ship broke in just two major pieces, the bow and stern, which was how the sinking was depicted in the 1997 film version of the catastrophe. David Brown, a Titanic historian, estimated before the latest find that the stern took 20 minutes to slide into the water.

“It turns out the Titanic was more merciful. It was over more quickly,” Brown said.

The 46,000-ton ocean liner was billed as “practically unsinkable” by the publicity magazines of the period. But it struck an iceberg on its maiden voyage and sank on April 15, 1912. About 1,500 people died.