Tip for captain and deck hand on 12 hour offshore trip?

are you asking this from the dock?

I have done 20% of total for great service

Most deck hands work for solely tips. Captain may guarantee something but often not much

So we typically do 20% to deckhand if they work hard, are personable etc it’s the captains job to put you on the fish

Customary for 20%. If they work hard for you, up to you. They usually don’t get paid by the boat.