Refrigeration Refit
Director of the New Zealand and Australian Land Company, William Soltau Davidson, sent an employee, Thomas Brydone, from New Zealand to investigate compression refrigeration units. In 1880 Davidson convinced the company to invest in refrigeration. Teaming up with James Galbraith of the Albion shipping company, they approached John Bell and Sons and J.J. Coleman, who had been behind the American chilled beef shipments.
As a result of negotiations, Albion agreed to refit the Dunedin with a Bell-Coleman compression refrigeration machine—this worked by removing air, compressing it, then releasing it to a lower pressure refrigeration chamber—in this case the hold – where the air cooled as it expanded. Using 3 tons of coal a day, this steam powered machine could chill the hold to 40 degrees Fahrenheit (22 °C) below surrounding air temperature, freezing the cargo in the temperate climate of southern New Zealand, and then maintaining it beneath zero through the tropics. The Dunedin was refitted in May 1881, the most visible sign being a funnel for the refrigeration plant between her fore and main masts, (sometimes leading her to be mistaken for a steamship). The refitted Dunedin arrived in Dunedin's Port Chalmers at the end of November 1881.
Read more about this topic: Dunedin (ship)