I’ve just been asked where births at sea would be registered and a Google search came up with one of the very useful National Archive Guides which is at http://www.nationalarchives.gov.uk/gettingstarted/looking-for-person/birthbritishnationalseaabroad.htm
Find My Past website has indexed the Births At Sea registers 1854 – 1887. Searching is free, but to view the details involves payment.
http://www.findmypast.com/home.jsp
