I see that his son William was born on 12 November 1855 in Kirkcudbright. Scottish 1855 birth certificates contain extra information not collected in any other year. In particular it should confirm John Pat(t)erson's age and birthplace, if you need such confirmation.
by entering 'Captain' or 'John' or 'Patterson' or 'Ticket No.11506'. for the period 1800 to 1899, no results were found!
Possibly a silly question, but did you try Paterson instead of Patterson?