Ah I see. Let's hope he told the truth when he joined the Navy - my OH's gt grandfather added 5 years to his age when he joined!
As an illegitimate child, he would probably have been baptised with his mother's surname and the first name of Fysher is very unusual, so I think that baptism is him. The original records are held by Portsmouth Record Office, but film/fiche copies can be viewed at LDS Family History centres for a fee.
Since you have his naval record, you could check out this site:
http://www.pbenyon.plus.com/Naval.htmlto see if the movements of any of the ships on which he served are detailed there.
Nell