Reliance on unstable ship (5,5)
I believe the answer is:
ocean liner
'ship' is the definition.
(ocean liner is a kind of ship)
'reliance on unstable' is the wordplay.
'unstable' indicates anagramming the letters.
'reliance'+'on'='relianceon'
'relianceon' anagrammed gives 'OCEAN LINER'.
(Other definitions for ocean liner that I've seen before include "Queen Mary, for example" , "Craft" , "Cruise ship" .)