Not sure about the rules on that.
What is the country of birth if it takes place on the “open” ocean (i.e, outside the 12-mile limit)?
Is it based upon ship registry, destination, departure, closest country at time of birth, based upon parent(s) citizenship, etc?
pssst....post-card from a ship was January/February, 1961 remember...
she wasn’t coming back, she was going going going...IMO
Depends on country
British includes colonies
http://www.theshipslist.com/Forms/BMD.htm
GRO Births at sea from 1837 to 1965 are available on 56 microfiche; however these are only indexes which contain names, dates and in some years, ship names. LDS Fiche numbers 6137268 - 6137322 The LDS Family Search Library Catalog will identify which fiche relates to which year.
marriage at sea by captains prohibited in us and uk