I appreciate that you asked that this topic be closed, but on the 1854 Indian General Service medal roll (Pegu clasp) is a Robert Lipsin, Carpenter's Crew, HMS Serpent. According to the Ship's Description Book he was born in Portsmouth and had signed-on on 5 October 1849, this being his first ship. At the time of signing on he was married, finally being paid off at Portsmouth on 19 January 1854. Given his occupation as a joiner and absence from the 1851 census I suspect this is your man.
Martin