The earlier K-class vessels, including Kurraba, Kirribilli, Koree and Kulgoa had only the sides of their upper decks enclosed leaving the ends open, with the roofs being squared off.
[1] The ferry trade to the North Shore increased rapidly and consistently from the turn of the century until the opening of the Sydney Harbour Bridge in 1932.
The Sydney Ferries fleet became one of the largest in the world - the bulk of which in number and capacity were K-class - and carried 40 million passengers per year by the 1930s.
A handful of the K-class ferries (Karingal, Karrabee, Kanangra, Kameruka) were in service until the mid-1980s having been converted to diesel in the 1930s and 1950s.
During the launch speech for Kaikai in 1906, Sydney Ferries acknowledged they were deliberately naming their vessels with Aboriginal words starting with the letter "K".