This is the "Soap Boat" M.B. Protex. She was built in 1908 and was originally named 'Waikare'.
In 1934 she was sold and used as a ferry to transport staff from the Palmolive soap factory from Balmain to various wharves around Sydney. She carried 20 souls.
She was renamed 'Protex' which was a popular soap manufactured by Palmolive, and hence the name, the "Soap Boat".