The Crimean War and the Indian Mutiny, not to mention tensions in North America, made it abundantly clear that Britain needed the capacity to rapidly dispatch troops around the world. A small army and worldwide commitments meant that the troops that were available might have to be deployed almost anywhere. The merchant fleet would do at a pinch, but, really, dedicated modern troop transports were needed. This led to the Euphrates class troopships, five huge iron hulled ships with screw engines, a full barque sail plan and a speed of about 14 knots. They were especially designed to fit the Suez canal, and could transport a full battalion of troops to India in just 70 days. The first to be built was HMS Serapis, the latest of several Royal Navy ships with that name, the last of whom had fought at the Battle of Flamborough head in 1779, holding off two American frigates, sinking one and allowing a convoy of 40 merchant ships to escape.
This Serapis was virtually unarmed, just 3x 4dr guns, her potency lay in her cargo. She was soon in use, rushing the 67th (South Lincolnshire) regiment across from Dublin to Canada in August 1867 in response to Fenian attacks from the United States. Not just the soldiers either, their wives and children, at least one child being born en route, Charlotte Serapis Soady Jackson (http://www.freewebs.com/iamanoxymoron/nottinghamlinks.html).
In 1868 the Serapis took part in the Abyssinian campaign, transporting 150 Hales rockets and a mountain battery and 6,000 rounds from Bombay to Zula on the Red Sea.
HMS Serapis. At some point in her early career she was painted white, and pretty spectacular she looked.
In 1869 she headed back to Canada, this time with immigrants not soldiers. The new iron warships needed far less men to make and maintain, leading to high unemployment in dockyard areas like Portsmouth. One government response was to encourage immigration, with free passage for artisans and labourers who had worked at the docks for at least a year, and their families. Between 1869 and 1870 over 2,000 dockyard workers and their families left for Canada, travelling on troopships like the Serapis. Her contribution in April 1869 took 707 passengers (326 males, 166 females and 215 children under 12) from Portsmouth to Quebec, on an 18 day sea journey to, hopefully, a better life.
However, most of the life of the Serapis was plying the route between Britain, Alexandria and India, in an endless rotation of troops. She was good at it, working until 1894, far beyond most ships built at the same time. As an example, in January 1874 she transported the 13th Hussars from Portsmouth to Bombay, 430 men including amongst others, 6 sergeant-majors, 16 sergeants, 29 corporals, 7 farriers, and 358 rank and file. And their families - but no horses, the 13th taking over those from the 21st Hussars in Lucknow.
The Serapis´s moment of glory came in 1875 when she was chosen to transport the Prince of Wales to India to mark Queen Victoria becoming Empress. This entailed copious modifications, and fabulously furbished state rooms were installed. There was a Royal Marine band and even huge blocks of ice kept in the hold. She called at Bombay, Ceylon, the Portuguese colony of Goa, and Aden before returning home to Portsmouth.