The vessel Cathy wrecked (5)
I believe the answer is:
yacht
'the vessel' is the definition.
(yacht is a kind of vessel)
'cathy wrecked' is the wordplay.
'wrecked' indicates an anagram.
'cathy' with letters rearranged gives 'YACHT'.
(Other definitions for yacht that I've seen before include "Pleasure craft" , "Pleasure-boat" , "Luxury purchase" , "Type of boat" , "Sailboat" .)