In my experience censuses taken close to the date of birth are normally fairly accurate, but those taken a long time later can be less accurate with both the date and place of birth.
Registration of births in England only started on 1 July 1837, so you won't find a birth registration if he was born before that.
I think this is probably his marriage:
Name George Henry Hewson
Birth Date 1839
Age 21
Spouse's Name Emily Peat
Spouse's Birth Date 1840
Spouse's Age 20
Event Date 08 Jan 1860
Event Place St. Peter-The-Great, Chichester, Sussex, England
Father's Name William Hewson
Spouse's Father's Name Charles Peat
Citing this Record
"England Marriages, 1538–1973 ," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:N6L9-5JJ : 10 February 2018), George Henry Hewson and Emily Peat, 08 Jan 1860; citing St. Peter-The-Great, Chichester, Sussex, England, reference 440, index based upon data collected by the Genealogical Society of Utah, Salt Lake City; FHL microfilm 1,068,511.
I think this may also be him:
Name:
George Henry Hewson
Gender:
Male
Birth Date:
16 Mar 1837
Birth Place:
Chichester, Sussex
First Service Date:
1 Jan 1873
First Ship Served On:
Excellent
Last Service Date:
1 Jul 1885
Last Ship Served On:
Excellent
Service Number:
51824
Source Citation:
The National Archives of the UK; Kew, Surrey, England; Royal Navy Registers of Seamen's Services; Class: ADM 188; Piece: 24
https://search.ancestry.co.uk/cgi-bin/sse.dll?indiv=1&dbid=60522&h=515209&tid=&pid=&usePUB=true&_phsrc=UBH2086&_phstart=successSource