Ancient ark builder (4)
I believe the answer is:
noah
'ancient ark builder' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for noah that I've seen before include "Biblical sailor" , "Sailor who ran aground on Mount Ararat" , "Biblical shipbuilder" , "The first known boat builder (4)" , "A very early sailor" .)