Characters in a pea-green boat see eye to eye (5)
I believe the answer is:
agree
'see eye to eye' is the definition.
(if two people see eye to eye they agree on things)
'characters in a pea-green boat' is the wordplay.
'characters in' indicates the answer is hidden within the clue.
'AGREE' is hidden in the letters of 'pea green boat'.
(Other definitions for agree that I've seen before include "Enjoy view in common" , "Have the same opinion" , "Have the same idea" , "suit" , "Accord, match" .)