Sort of vessel one found in posh port being renovated (9)
I believe the answer is:
troopship
'sort of vessel' is the definition.
'one found in posh port being renovated' is the wordplay.
'one' becomes 'i' (Roman numeral).
'found in' is an insertion indicator.
'being renovated' indicates anagramming the letters.
'posh'+'port'='poshport'
'poshport' anagrammed gives 'troopshp'.
'i' put inside 'troopshp' is 'TROOPSHIP'.
(Other definitions for troopship that I've seen before include "As carrier" , "boat" , "Army vessel" , "Military transport vessel" .)