Scotland John Davidson and Barabra Ballintine

Hi, I'm looking for my 5xgreat grandparents.
John DAVIDSON married Barbara BALLINTINE in 1841 in Grenock,Renfrew,Scotland.Barbara was born in 1820 in Aberdour,Fifeshire,Scotland. They only had one son, Christopher John born 1843 in Grenock, Renfrew,Scotland.
John was a mariner and had died at sea by the time of the 1851 census. Barbara went to live with her brother, Arnes BALLINTINE,born 1815 in Arberdour;and nephew, Robert born 1841 in Grenock. It is presumed that the wife of Arnes had also died as she is not on the census.
I would be greatful for any help or insight.
Many Thanks,
Erin