I realise this message is rather old, but James Holman was my great great Uncle. He was a partner in Heinke. My grandfather was also a marine engineer and they both worked with the Australian Pearling industry at various times in 1913=15. Oddly enough I don't actually have the census information. I have a fair amount amount of information and I am in touch with some of his descendants.
If you are still interested, I would love to know your interest and connections.