Thank you.Thats great. Part of the problem you are faced with is no central index of Merchant Seamen was kept between 1857 and 1913. Records of Merchant Seamen for the period of WW1 have been destroyed. So Crew Agreements are the only game in town
I suggest that you try and obtain the relevant Crew Agreement of MINERVA O/N 67556 to see if he is there, if not, you can at least eliminate that particular vessel from your search. A trip to Kew would be your best bet. It's a pity that 3 of her 1881 Crew Agreements which are online, contain a list names, the 4th one do's not.
The official number of the other 3 Steamers named MINERVA are as follows. 58331, 44812, 71878.
I came across a seaman named G Piscopo born 1925 in Adelaide. Any connection?