PETER OWENS explains why a 19th century submarine is sitting far inland at Middlemarch in Central Otago.
BEFORE GABRIEL READ found gold near Lawrence in Central Otago, Dunedin was a small, Free Church of Scotland settlement of no special mark. With the Central Otago gold rushes beginning in the 1860s after Read’s discovery of gold, it changed dramatically.
By the end of the 1860s most of the easily mined gold had been taken and it then became a much tougher proposition. The lawless element seeking quick returns soon left Dunedin and Central Otago for California, but people of stronger determination remained. As gold had been recovered from the smaller, slower and shallower rivers of Central Otago, they deduced there was also gold in the bigger rivers such as the Clutha and the fast-flowing Kawarau.
Many lives were lost in attempts to mine for gold on the major Otago rivers and would-be gold miners set about finding alternative ways of finding gold. Many of them took to the hills and there were miners’ camps at places on the Old Man Range and others where thousands of men from all over the world based themselves to work the mountain streams. Others sought ways to mine the beds of the big rivers and came up with some ingenious proposals.
One of these proposals was from an Australian, RW Nuttall, who arrived in gold-fevered Dunedin in 1872 from Melbourne seeking investors in a scheme he had devised for mining the beds of the big rivers. His scheme involved a ‘submarine boat apparatus’ designed by a Monsieur Villaine for ‘digging and sluicing underwater’. Villaine had designed the machine in the 1840s and a prototype had been built.
At first, investors were readily forthcoming and a prospectus for a New Zealand Rivers Gold Mining Company was issued, to use the patents taken out by Messrs Villaine and Groundwater for the submarine boat. Unfortunately for Nuttall, there was not enough financial interest in the scheme and it was dropped.
The project was then taken over by the New Zealand Submarine Gold Mining Co and the construction contract went to the Dunedin Iron Works (RS Sparrow and Co) and the South Dunedin Railway Foundry built what was named the Platypus, which was delivered in August 1873. Delays with final fittings postponed the launch of the first submarine constructed in the colony until December 14, 1873.
Because of the demand for dredges and other heavy machinery for the gold fields such as stamper batteries, Dunedin engineers were not overwhelmed by the task of building the Platypus. It was an iron cylinder constructed of 3/8-inch plates with a length of 35 feet (10.6 metres), and the diameter was seven feet (2.2 metres.) A paddle or wheel box was fitted on each side and between an iron hatch covering which provided entrance into the hull.
An opening on the hull’s bottom was fitted with a water/airtight door to be opened when the vessel was on the bottom, providing access to the riverbed. Inside at the stern was an air reservoir to hold pressures of six atmospheres (90 psi). A tube passed through the reservoir provided communication to both ends. The reservoir was connected to four air pumps fitted across amidships and driven by motive power supplied by water wheels. The two wheels, driven by river current force, were connected to a main shaft.
A belt drove a countershaft attached to the air pumps which supplied fresh air through a tube connected to the surface. When submerged, a rudder was operated by two tiller ropes, or at a deck handle when the sub was on the surface. When submerged, the wheel boxes would fill with water. The lower wheel parts were neutralised by water in the upper part of the boxes and to overcome this, a pipe connected to the interior of the vessel supplied compressed air to expel water to within six inches of the box bottom. This allowed the wheels to operate easily.
Once on the river bed the bottom door could open and enable gold bearing riverbed to be scooped into a sluicing apparatus fitted inside the hull. When submerged the sub was moved by a crab-winch. The sub would be floated clear of the bottom and winched ahead to a new position and then lowered with a brake.
With the chance to view a possible revolution in mining without having to pay for it, the canny Scots of Dunedin thronged the Rattray Street wharf of the city’s inner harbour on December 1873 to watch the first test of the odd-looking submarine.
The vessel carried a crew of eight for the test and they manned the pumps, to expel water from the ballast tanks and to circulate air in the vessel.
Slowly it sank to the bottom of the harbour and to acclaim from the spectators and, of course, the investor, it rose once again to the surface.
Buoyed up with the success of this first trial, a second one was also undertaken in February of the following year. This was even more successful.
The Platypus submerged and took 45 minutes to reach the bottom of the harbour. Shortly afterwards, the bottom hatch was opened and there was no in-rush of sea water. The crew collected shells off the bottom, as well as a fishing line and seabed mud. The bottom hatch was closed and there was no problem with pumping out water to raise the vessel from the bottom.
On this occasion the Platypus took 14 minutes to reach the surface and everyone was happy with its performance. Douglas, the engineer heading the project, remained on the surface for this dive. He reported that provision had been made in case of foul air below to purify it by use of a quantity of limewater.
Despite the successful trialling of the submarine, the New Zealand Submarine Gold Mining Co fell into insolvency in April of 1874 and the submarine with its patent rights was auctioned off in Dunedin. They were purchased for $800 and the sub stripped of its fittings. The Platypus never sailed again.
The shell lay for many years by a Dunedin wharf until 1924 when, following a lecture on submarines at the Dunedin Officers Club, recalling the building of the Platypus, a member of the club bought the rusted remains. After cutting the hull into three sections he sent them off to Central Otago. Today a section of the submarine is on display at the Middlemarch Museum.
The central section served as a domestic water tank on Pukerangi Station. The bow and stern sections were donated to the Middlemarch Museum by WF Stewart, the owner of Pukerangi Station near Middlemarch in 1991, where they remain to this day.
These remains have been exhibited outside the small museum and fearful of deterioration of the submarine relics, the museum is currently raising funds to lift it off the ground, clean and protect the surface, cover it with a roof and provide signage to tell its intriguing story.