Although much of the New Zealand coastline had been charted by the time settlement started around 1840, surveyors continued to map the harbours. However a comprehensive hydrographic survey of the coast was still needed.
The Great Survey: the Acheron and Pandora
A survey vessel, the paddle steamer Acheron, under the command of Captain John Lort Stokes, was dispatched by the British Admiralty and arrived in Auckland in November 1848. The first step was the erection of a trig station (for trigonometrical surveying) on what is now Windsor Reserve in Devonport on Auckland’s North Shore. Another vessel, the Maori, surveyed the western shores of the Hauraki Gulf from Whangaparāoa to Cape Rodney.
A box of clocks
The Acheron had been fitted out with the latest equipment for survey work. Charlotte Godley, a Wellington settler, wrote that, ‘The chronometers are a sight to see; there are about two dozen, in a very safe little lock-up, each ticking away according to its own idea of the “time of day”, some by Greenwich, and all different; but from the whole … they give us the true time every day at noon.’ 1
In 1849 the Acheron travelled to Banks Peninsula, where Stokes surveyed Port Cooper (Lyttelton Harbour) and neighbouring bays, as well as venturing inland to establish survey points. He assisted the New Zealand Company’s surveyor, Joseph Thomas, to map out a site for the Canterbury settlement.
The ship went to Otago, and then back to its winter quarters in Wellington. In the summer of 1850 Stokes and his crew accurately charted the east coast of the South Island, and in the summer of 1851 Foveaux Strait and Fiordland. Some of the crew were sent to survey other parts of New Zealand.
In May 1851 the Acheron was replaced by the smaller sailing brig Pandora, partly because of the cost of coal to fuel the Acheron. Under Commander Byron Drury, its officers spent the next four years painstakingly filling in the gaps on the charts of the north-west coast of the North Island.
Completion of the survey
By 1855, 250 sheets of fair tracings of the New Zealand coastline had been sent to the British Admiralty for incorporation into charts. Fifty were published within the next six years, and others later. The New Zealand Gazette made the information immediately available in the form of sailing directions. A list of astronomically determined positions was also published in the Gazette in 1852 and served as a base for later surveyors’ work. As recently as 1969 one or two charts created by Stokes and his officers were still in use.