John Patterson was born on 29th March 1827 to Samuel Patterson, a servant, of Gategill, in the parish of Borgue and Anne Stott of Gatehouse. His parents were married in Gatehouse in November 1826. Samuel Patterson was born in Ireland around 1800 and Anne Stott in Gatehouse around 1805.
In 1841 the family lived at Conchieton in Borgue parish. Samuel was an agricultural worker. There were 3 children, John (14), Jane (12) and Samuel (10).
By 1851 they were at Boreland of Borgue. Two more children had been born, William (9) and James (

. Samuel Patterson was described as a farm labourer. The 3 older children had all left home.
In 1861 Samuel and Anne were at Muiryard, Borgue parish. A son James (18) was living with them. Interestingly enough James' occupation is given as tailor.
Samuel Patterson died at Tannymass, Borgue parish, in 1869. His parents, presumably left behind in Ireland, were Samuel Patterson, Farmer, and Agnes Wallace.
Anne Stott died in Millburn Street Kirkcudbright in 1876. Her parents were John Stott, labourer and Ruth McBride.
Although Gategill, Muiryard and Tannymass are all in the parish of Borgue, they lie to the north of the main A75 between Gatehouse and Twynholm off the Old Military Road.
John Patterson, born 1827, got his seaman's ticket, no. 272612, at age 18. This was in 1845. He sailed out of Liverpool for several years.
Then it seems he was for a time working on ships sailing out of Charlottetown, Prince Edward Island, Canada. By 1852 he was noted as Master of several ships before gaining his official Master Mariner's ticket, no. 11506, in 1854. The address on his ticket is given as 32 Park Street, Toxteth Park, Liverpool. Have found no information as yet about him or the ships he sailed on between 1854 and his death.
He married Margaret Robertson in Borgue parish in 1854. Their first child a daughter died. Their second child William was born in Union Street, Kirkcudbright in 1855.
In 1861 he was living in Park Street, Toxteth Park, Liverpool, with wife Margaret and two children, William (5) born Scotland and John (3) born Liverpool.
According to your research, Margaret Robertson, must have been back in Gatehouse by 1864.
I know nothing more about John Patterson except that the date given for his death at sea in the England & Wales, National Probate Calendar (Index of Wills and Administrations), 1858-1966 is 4th April 1868 (not 1867 as written on the headstone in Gatehouse). Place of death on this calendar is stated as Scotland.
I agree that John's story is very intriguing! Lots to discover yet.