Check into earlier vessel (8)
I believe the answer is:
schooner
'vessel' is the definition.
(schooner is a kind of vessel)
'check into earlier' is the wordplay.
'check' becomes 'ch' (I've seen this in other clues).
'into' indicates putting letters inside.
'earlier' becomes 'sooner' ('sooner' can be a synonym of 'earlier').
'ch' placed into 'sooner' is 'SCHOONER'.
(Other definitions for schooner that I've seen before include "Large beer or sherry glass" , "Old sailing ship and tall sherry glass" , "Swift sailing vessel - sherry glass" , "In the main it is" , "Item used for drinking" .)