Green’s Dictionary of Slang

1. (N.Z.) a prostitute who works on docked ships; a descendant of the 19C Maori ship-girl.

1978

N. Hilliard Glory & Dream 209: He had to push his way in among the British seamen and their camp-followers: the shipgirls, the boaties.

2. (Aus.) a fan of yachting; also attrib.

2012		A. Prentice ‘The Break’ in Crime Factory: Hard Labour [ebook] The wrinkled old boatie in a captain’s cap [...] and deck shoes.
2023		D. Whish-Wilson I Am Already Dead 106: Laver continued playing the country gent, or the boatie wanker, Lee couldn’t tell which.