There was a natural tension between Shaw’s Quint, the working-class hero, and Dreyfuss’s Hooper, a city boy; it may have been a case of an experienced actor taking the reins.
Co-star Roy Scheider thought Dreyfuss's arrogance sparked the feud, citing, “He [Shaw] really thought Dreyfuss needed a slapping down... young punk with no stage experience..."
The incident that seems to be the main source of the rumor was when Shaw was walking the gangplank with a drink in his hand and asked Dreyfuss for help.
Dreyfuss recalled, “I said, 'Do you really want my help?' He said he did and I took his drink and I threw it in the water. Every drinker on that crew went 'ooooh.'”
Steven Spielberg also recalled Dreyfuss being dared by his co-star to jump from the mast into the water, adding, "Robert would basically humiliate Richard into taking a chance.”