The England-bound voyage of the first refrigerated cargo ship in 1882 creates a booming export industry for New Zealand lamb and mutton.
The first attempt to ship refrigerated meat had been made when the Northam sailed from Australia to the UK in 1876; however, the refrigeration machinery had broken down en route and the cargo was lost.
In 1877, the steamers Le Frigorifique and Paraguay had carried frozen mutton from Argentina to France, proving the concept of refrigerated ships, if not the economics.
In 1879, the Strathleven, equipped with compression refrigeration, had sailed successfully from Sydney to the UK with forty tons of frozen beef and mutton as a small part of her cargo.
The clipper sailing ship Dunedin, owned by the New Zealand and Australian Land Company (NZALC), had been refitted in 1881 with a Bell-Coleman compression refrigeration machine—this steam powered freezer unit works by compressing air, then releasing it into the hold of the ship.
The expanding air gets cooler as it expands, cooling the cargo in the hold.
Using three tons of coal a day, this steam-powered machine can chill the hold to 40°F (22°C) below surrounding air temperature, freezing the cargo in the temperate climate of southern New Zealand, and then maintaining it below freezing (32°F (0°C)) through the tropics.
The Dunedin's most visible sign of being an unusual ship is the funnel for the refrigeration plant placed between her fore and main masts, (sometimes leading her to be mistaken for a steamship, which have been common since the 1840s).
The Dunedin sails from Port Chalmers, New Zealand in February 1882 with 4331 mutton, 598 lamb and 22 pig carcasses, 246 kegs of butter, as well as hare, pheasant, turkey, chicken and 2226 sheep tongues and arrives in London UK after ninety-eight days sailing with its cargo still frozen.
After meeting all costs, The NZALC company makes a £4700 profit from the voyage.
