Ahh, so his first name was Stephen/Stefan? You didn't mention that before, or I must have overlooked it.
I'm not sure there are Navy ships crews online... I never needed them, so I didn't look for them.
Next week, when I will have more time, I'll see whether I can find something.
I wonder whether there could be any misspellings in names and places...? Do you have a scan of the original documents?