The introduction of the steamships on a large scale in the late 19th century saw African and Asian sailors becoming a central component of the workforce of the British merchant marine. This development was met with considerable resistance from British seamen who saw these workers as a cheap labour force that would undermine their established position. This article interprets the steam empire as a set of overlapping webs, comprising the shipping companies, British diasporic labour and Indian Ocean seafarers. It traces how a racialized politics was generated within these webs, and the major conflicts to which this gave rise.