Hi,
Not had any luck finding Lavinia but this could be William.
Ref RG9 500 folio 11 Vessel 'Union' (vessels were enumerated after the entries for Wharf Lane)
William Alldridge married age 34 barge master born Maidstone
John Alldridge not married age 29 barge mate born Maidstone
Vessel 'Union'
Port to which she belongs : Rochester
Tonnage 30
Description: Barge - coasting trade
Name of master - Wm Alldridge
Also found:
RG09 500 folio 7 page 7: 13 Wharf Lane, Maidstone
Susan Alldridge head wid age 63 washerwoman born Maidstone
and from FreeBMD
death William Alldridge age 44, Dec qtr 1870, district Thanet, ref 2a 476
The age of this death ties in with the William who is master of the vessel 'Union'.
Carol