Thank you for your reply to my message.I am from Newcastle, N.S.W.
My great-grandfather William Ernest Floyd, was born in Middlesex, England 25.2.1882 and was a merchant seaman, eventually residing in Sydney around 1920.His parents were William and Emily (nee Gates) whom I believe did not stay married very long; William senior remarrying and having more children and William junior staying with his father until aged around 12 (about 1894) when he "ran away to sea".
Perhaps William senior was your great-grandfather (Samuel's) brother?I think my William senior's father's name was John but I'm not sure. If it turns out to be James then we might be related.I will apply for some bdm certificates from England and be in touch again if it seems we might be related.
Thanks again for your reply and good luck with your research!