Gunner's Mate John Cockrell was born in Exeter, Devon in October 1821 and entered the Royal Navy as a Boy Rating aboard H.M.S. Wolverene in March 1839. Advanced to Ordinary Seaman in June 1840 and to Able Seaman in April 1842, he joined H.M.S. Castor as a Captain of the Foretop in May 1849, seeing service off South Africa between December 1850 and February 1853. Next posted to H.M.S. London as a Gunner's Mate in July of the same year, he was present in operations off the Crimea, including Sebastopol. Cockrell was paid off from H.M.S. Edinburgh in August 1856.