Jet Boat Shows Its Paces

The jet age hit the water in Gisborne last month with a muffled roar and a column of flying spume when H.W. Grundy's speedboat Aurora went through a two-hour demonstration with a "Photo News" cameraman aboard.

Aurora is a 20ft craft with a beam of 7ft 2in, built by Mr Grundy. In the stern there is a Ford Zephyr engine geared to a Hamilton Marine jet unit. This takes in water through an opening in the bottom of the boat and expels it through a nozzle at something like 1100 gallons per minute. At full bore the jet will drive the Aurora at 22 to 24 m.p.h. It makes no difference to the speed of the boat if the jet comes out in the water or the air.

In Turanganui River, impression of speed and power is given by jet spray and silvered wake.

Above the Waimata island, Aurora hits top speed with Mr Grundy at the controls. Big advantages of jet are its mechanical simplicity, shallow draught (only a few inches), and exceptional manoeuvrability.

First stage of "Photo News" trip in jet boat was up Waimata River, where mirror-smooth water reflected stately homes and beautiful views in plenty. Picture above shows lower reaches looking back to Kaiti Hill. At right are two Clifford Street homes, while below a perfect reflection is caught by the camera near Harris Street.

Picture at right was taken coming down the Waimata below the island. Again the jet and the Aurora' s wake make a pattern of turbulent vigour on the river's calm surface.

Action pictures of the Aurora

On a perfect spring morning, clouds and hills are mirrored in the river

More views taken during trip up Waimata River

After the river trip the Aurora headed out to sea for a quick look at the Port Hobart loading in the roadstead.

The sea was almost as calm as the Waimata and proved no test for her handling in rough water, but back in the Turanganui River (below) Mr Grundy put the Aurora through her paces. She made some striking patterns as her owner threw her about in the channel.

The marine jet unit which gives the Aurora its propulsion. The pump at right, driven by the shaft, top right, takes in water through bottom of boat and drives it through nozzle at left Nozzle has a flap arrangement which can direct jet to left or right, eliminating need for rudder.

The Aurora on its trailer, with the hoist in position. This holds boat up while trailer is driven away, facilitates easy handling at river-side.

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The Gisborne Photo News

No 28 : October 18, 1956

Jet Boat Shows Its Paces