One of the things that makes the film Jaws so effective is that you don’t get a good look at the titular shark until the very end of the movie, where its sheer size terrifies the heroes who go out to sea in hopes of killing it. After the shark is first seen, a shocked Chief Brody utters, “You’re gonna need a bigger boat, ” famously improvised by actor Roy Scheider.
He repeats the idea repeatedly for the rest of the scene, begging Quint to return to shore for a better vessel, even though the line wasn’t part of the original script. Apparently, the line was something of an in-joke to the actors, who had complained to Steven Spielberg about the size of the barge that carried the cast, crew, and equipment out to the water. It turned out perfect for the scene and now is one of the movie’s best-known lines.