There are probably a number of ferries - both in the Sydney area or other parts of NSW - that may fit. Where did he die? I can remember the ferry in 1950s/60s across the Clarence river near Maclean - used to hold up the traffic on the Pacific Highway - I can't remember when the bridge was finally built. Local family history societies may well have information about local ferries - so knowing his location would be useful.
I have a relative who was a ferry master in Qld in the 1930s-50s - on ferries in Moreton Bay.