Boat-deck application (3,3)

I believe the answer is:

tar oil

'boat-deck application' is the definition.
(I've seen this in another clue)

This is the entire clue.

I've seen this clue in the Newsday.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.