Editors Note ; I cannot find any historical data in relation to this actual image, I would hazard a guess that "Miss Manapouri" would have been of Hamilton jet vintage and construction. And of course for New Zealand this invention by Charles William Hamilton in the 1950's were he pioneered the first commercial waterjet.
https://en.wikipedia.org/wiki/Bill_Hamilton_(engineer)
Sir Charles William Feilden Hamilton OBE (26 July 1899 – 30 March 1978) was a New Zealand engineer who developed the modern Jetboat, and founded the water jet manufacturing company, CWF Hamilton Ltd.
Hamilton never claimed to have invented the jet boat. He once said "I do not claim to have invented marine jet propulsion. The honor belongs to a gentleman named Archimedes, who lived some years ago." What he did was refine the design enough to produce the first useful modern jet boat".