Common man on a vessel gets a prize (7)
I believe the answer is:
jackpot
'a prize' is the definition.
(I know that jackpot is a type of prize)
'common man on a vessel' is the wordplay.
'common man' becomes 'jack' (I've seen this before. I am not sure about the 'common' bit.).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'a vessel' becomes 'pot' (type of container).
'jack'+'pot'='JACKPOT'
'gets' acts as a link.
Can you help me to learn more?
(Other definitions for jackpot that I've seen before include "Great thing to hit?" , "more than just change for the better" , "Hit the . . . . . . . - win the big prize" , "The big pay-out - hit it" , "major win" .)