Caretaker's cold, working EEC rig at sea (9)
I believe the answer is:
concierge
'caretaker's' is the definition.
(concierge is a kind of caretaker)
'cold working eec rig at sea' is the wordplay.
'cold' becomes 'c' (eg on taps).
'working' becomes 'on'.
'at sea' indicates anagramming the letters.
'eec'+'rig'='eecrig'
'eecrig' is an anagram of 'cierge'.
'c'+'on'+'cierge'='CONCIERGE'
(Other definitions for concierge that I've seen before include "Residential block porter" , "Caretaker of an apartment building" , "One books tickets etc for hotel guests" , "Doorkeeper of hotel or apartment building" , "hotel employee" .)