Built for the Union Steamship Company, and working for this line from 1879 to 1925, this ship made history by being the first vessel to be constructed of mild steel, and also the first to be fitted with twin bilge keels. Rumour has it that the ship was originally ordered as the private yacht of a wealthy prince, but that he either died of could not afford to pay for her,adn it was sold on the stocks to the Union Line. This story was never officially verified, but as she was quite different in design to any other vessel built for the Union Line, it would seem quite a reasonable tale.
Rotomahana was launched on 5 June 1879, leaving London on 5 August on jer delivery voyage. She picked up 100 passengers at Plymouth, and then went around the Cape of Good Hope, arriving in Melbourne on 22 September, before continuing on to Port Chalmers, where she arrived on 1 October. She was the subject of much interest wherever she called, both because of her yacht-like lines and internal fittings. She had accommodation for 140 first class, 80 second class and 80 third class passengers. For some years yards were carried on the foremast so that sail could be raised when wind conditions were favourable, to increase speed and cut coal consumption.
On 9 October 1879 Rotomahana left Wellington on her first voyage to Sydney, calling at Napier, Gisborne, Auckland and Russell en route. She remained on this route for the next fifteen years, although limited cargo space combined with excessive coal consumption at high speed made her an expensive vessel to operate, resulting in her often being laid up during off peak times.
In 1894 she took on the Bass Strait ferry service between Melbourne and Launceston for several months before doing to coastal services around New Zealand. In 1897 she began service on the Wellington to Lyttleton ferry run, where she remained for several years. Between April and August 1901 six new boilers were installed to replace the original four, and on returning to the run, she averaged 16 knots between Lyttleton and Wellington, in a journey of 10 hours and 18 minutes.
After twenty years of service between the North and South Islands, in May 1907 Rotomahana took up the route between Melbourne and Tasmania once again.
She spent "the rest of her career crossing Bass Strait, serving on the route throughout the First World War, and only being taken out of service when Nairana arrived in 1920. Rotomahana arrived in Melbourne on 16 december 1920 at the end of her last commercial voyage, and was then laid up, remaining idle for over four years before being sold at an auction on 3 April 1925 to Power & Davis, a firm of Melbourne shipbreakers. Over the next three years the work of dismantling the old vessel proceeded slowly at Port Melbourne, and then on 29 May 1928 the hulk of this once proud vessel was towed through Port Philip Heads and scuttled in the ships' graveyard three miles out to sea".
John Bayne brought his new bride back to NZ on this vesel, from Australia.
References: "Passenger Ships of Australia and New Zealand" Vol I 1876 - 1912 - Peter Plisoma