Told to go in a ship, agrees (7)
I believe the answer is:
assents
'agrees' is the definition.
(assenting is a kind of agreeing)
'told to go in a ship' is the wordplay.
'told to go' becomes 'sent' (I've seen this in another clue).
'in' indicates putting letters inside.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'a'+'ss'='ass'
'sent' placed inside 'ass' is 'ASSENTS'.
(Other definitions for assents that I've seen before include "Expresses agreement" , "Agrees, complies" , "Gives nod" , "Says yes" , "Accedes, acquiesces" .)