Vessel caught going over simple boat (5)
I believe the answer is:
craft
'vessel' is the definition.
('craft' can be a synonym of 'vessel')
'caught going over simple boat' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'going over' says to put letters next to each other.
'simple boat' becomes 'raft' (I've seen this before).
'c'+'raft'='CRAFT'
(Other definitions for craft that I've seen before include "Vessel; skill" , "Creative activity" , "Guile" , "boats" , "Cunning; boat, ship" .)