Although steamships operated as mail couriers in the British Isles from the 1820s, they were initially employed in Southeast Asian waters as military vessels in naval operations against indigenous pirate vessels. Part of the early reluctance in adopting steamers for use as mail and passenger transports stemmed from the relatively high costs of running the coal-hungry ships, which had a low fuel mileage. It was only in 1845 that a dedicated mail steamer route covering Ceylon, Penang, Singapore and Hong Kong at monthly intervals was put into operation by the British-owned Peninsular and Oriental Steam Navigation Company (more commonly known as P&O). From the 1850s onwards, steamers became more common as innovations in nautical technology such as the screw propeller, iron hull, surface condenser, and compound engine lowered their operational costs.
