1975 Spielberg film featuring the line: "You're gonna need a bigger boat” (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
jaws
(Other definitions for jaws that I've seen before include "Talks at length; grippers" , "lectures" , "Bond henchman" , "Gripping part of wrench" , "Shark film" .)