You do not need to go inside the building to find this cache.
I remember my first introduction to the muesum was during an appeal for funding for the SOS project - save our submarine. Wait why is there a submarine in Middlemarch? Well there is a great story behind the failure of Dunedin's early submarine vechile, known as the platapus.... read below for what happened.
Cache is at S45 29.AAB E170 0C.DEC
Below the SOS information panel (to right of entrance door) there is a marble plaque, use this to answer the following;
A = Stone was laid 2Ath April.
B = Number of times Otago is written.
C = Number of letters in the first word.
D = On the top line there is a three digit number, Third digit minus First digit.
E = Last digit of the year the foundation stone was laid.
Check sum = 27
New Zealand was gripped by gold fever after its discovery in Otago and West Coast rivers. Once the easily accessed gold was exhausted attention turned to dredging deeper rivers. So there was need for a submarine.
The Platypus had its maiden voyage in Otago Harbour just three years after Jules Verne released the underwater science fiction classic 20,000 Leagues Under the Sea in 1870.
The 150-year-old submarine is thought to be one of only two of its vintage still in existence.
"In the history of submarines it's quite amazing and would certainly be the only one ever built in New Zealand,"
Designed to work in Otago goldfield rivers, the Platypus was an iron cylinder constructed of 3/8-inch plates (total length 35 ft/10.6m, diameter 7ft 2ins/2.2m.) A paddle or wheel box was fitted on each side and between an iron hatch covering allowing 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 which provided communication to both ends. The reservoir was connected to four air pumps fitted across midships and driven by motive power supplied by water wheels. The two wheels, driven by river current force, were connected to a main shaft.
By 30 January 1874, the problems were resolved and Villaine and his son, Mr Douglas the engineer in charge of the construction, Mr Harvey a director, and four men to work the pumps entered the submarine through the entrance dome; this was then screwed in place sealing the eight men inside. The crew commenced pumping air to sustain life and emit water into both ends to submerge the sub. It took 1hr 50mins to reach the bottom however, as it was a shallow depth for the first test, part of the upper structure remained above water.
On bottoming, the lower door was to be opened and floats with flags sent to the surface. After two hours no signals had appeared and it was decided to signal them to surface. They had been submerged long enough to convince the most sceptical. For the first half hour the sub rose slowly until the tops of the paddle boxes were above water. A strong squall came up and in the rough water the sub became jammed under the counter of the lighter. Concern for the eight men heightened as at least two must keep pumping until the entrance hatch was above the surface; it was decided to tow the sub to shallower water so the hatch was above water. It was with some relief that the hatch fastenings were seen to move and the engineer emerged with his fellow divers.
The four pump crew looked exhausted as it was some 4hrs 20 mins since the crew first entered the Platypus. Mr Douglas reported the sub had been impeded in surfacing through leakage in the valves of the air pump and enough pressure could not be generated to expel the water. He had not opened the bottom hatch as he was concerned there would not be enough pressure to keep the water out. Although the trial was not termed a decided success, it was a long way from failure.
A further trial was carried out on 4 February and declared an unqualified success. The Platypus submerged and took 45 minutes to reach bottom; after a few minutes the bottom hatch was opened and there was no difficulty with keeping water out. Shells were collected off the bottom, also a fishing line and seabed mud. The bottom hatch was closed and there was no problem with expelling water to raise the sub from the bottom. The ascent took 14 minutes. The jubilant crew emerged hailing the dive a success. Mr Douglas, who remained on the surface for this dive, reported that provision had been made in case of foul air below to purify it by use of a quantity of limewater.
Unfortunately a lack of investors brought the project to a stand-still and it languished on the wharf in Dunedin for 10 years before being moved to the city's McLeods Soaps.In 1924 it was cut up into pieces and sold to a farmer in Barewood near Middlemarch where it remained (acting as grain store) until it was donated to the Middlemarch Museum in 1991.
Information sources from museum, ODT and Stuff news articles.