There is some explanation of what happened during the filming of Jaws on IMDB
. According to the various trivia notes, Shaw wrote his own speech when the principal writers for Jaws couldn't agree upon how to tell the story. On the first try he did try to read it as drunk as he was supposed to be based on the scene but that filming was unusable, so he asked Spielberg to do in again which supposedly was done in one take.
As other notes point out: too bad that this telling is largely fiction. That the USS Indianapolis
did sink with some of the 880 initial survivors dying from shark attack is true, but it was after the ship was assigned to another mission after delivering bomb parts (including the enriched uranium) for Little Boy which was dropped on Hiroshima. The Indianapolis had returned to Guam and was not under radio silence while on its way to the Philippines. The ship very quickly sank about 12 minutes after being struck by torpedoes but they did send a distress signal which was heard but ignored by at least 3 naval radio stations. Before being spotted by a plane after 3 days, most of the initial survivors died due to lack of food and water and to exposure and to some shark attacks, but mostly what the sharks did was eat the bodies of the dead. Of the crew of 1196, 321 were rescued but 316 survived.
But as it was put in another movie
: "When the legend becomes fact, print the legend." It is still a gripping monologue.