There is a photograph in the Queensland State Library purportedly of Captain William Townsend. I have also seen a scan of the same image, but with the photographer's name and address and a pencilled inscription "B I Co". The photographer was W E Wright, and he was located in Forest Gate, Essex. I am researching this person to try to extend the timeline back from 1882 (W E Wright and Sons) which would be far too late.
Anyway, the "B I Co" is most likely the British India Steam Navigation Company, which started up in 1856 (and eventually became fully absorbed into P&O). The cap badge, as far as I can see, is consistent with the BI Co uniform, and the sleeve lace would indicate Third Officer rank. So, was Captain William one of the early sea-going staff of the BI Co? He was certainly in the right job at the right time and the right place.
The BISN eventually established the Queensland Mail, from UK via Batavia and the Torres Straits, Cooktown, Townsville and Bowen to Brisbane. It was on one of these ships, the Chyebassa, that my great grandfather and his family travelled in 1885.