Tries to get heated in a vessel (5)
I believe the answer is:
shots
'tries' is the definition.
(shot is a kind of try)
'heated in a vessel' is the wordplay.
'heated' becomes 'hot' ('hot' can be a synonym of 'heated').
'in' is an insertion indicator.
'a vessel' becomes 'ss'.
'hot' placed within 'ss' is 'SHOTS'.
'to get' is the link.
(Other definitions for shots that I've seen before include "See 2" , "Gunfire -- attempts" .)