“I am,” Cameron said. “I was in the water with the piece of wood putting people on it for about two days getting it exactly buoyant enough so that it would support one person with full free-board, meaning that she wasn’t immersed at all in the 28 degree water so that she could survive the three hours it took until the rescue ship got there.”
This – all of Jack’s death scene, in fact – is actually true to life. On that night in 1912, hundreds of Titanic passengers were left in the water from about 2:20 a.m. until after 4:10 a.m., when efforts finally were made to rescue them. Fifth Officer Lowe, like in the film, returned to the site of the sinking with a lifeboat. But he was much too late.