Patriarch of the Ark (4)
I believe the answer is:
noah
'patriarch of the ark' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for noah that I've seen before include "Old ship builder" , "Great Biblical boatman" , "Oh, an ark man" , "Biblical boat builder" , "His sons were Shem, Ham and Japheth" .)