Green’s Dictionary of Slang

(Aus.) a deckhand.

1993		Aus. Word Map 🌐 deckie [...] The deckie pulled the craypot over the side of the boat.
1996		Professional Skipper (NZ) 🌐 But the fact remains that there are times in a Skipper’s life when you find yourself with a boat-load of passengers, no deckie, and suddenly, urgently, nature calls.
2004		T. Winton Turning (2005) 146: In a town like this the available men were fat-gutted skippers [...] or the adolescent deckies.
2012		D. Whish-Wilson ‘In Savage Freedom’ in Crime Factory: Hard Labour [ebook] On the prison wireless I’ve heard Danny’s running wild, working as a deckie.