I am tracing a William Mann that married a Mary Elizabeth Buckley in 1867 in Lyttelton New Zealand. Family letters state that he was a seaman who came to NZ on the "Blue Jacket" as crew from what I understand apparently arriving in 1866. Is there any way of confirming this?
This particular line of family is at a dead end as I have no idea where he originated from. I have a couple of possible deaths with a likely one being in 1919 in Wellington. I am quite keen to explore this one further but am stuck

Any suggestions appreciated
Anna