Having gathered sail, put off returning across centre of Med (6)

'having gathered sail' is the definition.
I can't judge whether this definition defines the answer.

'off returning across centre of med' is the wordplay.
'off returning' becomes 'ree' (I can't justify this - if you can you should give a lot more credence to this answer).
'across' says to put letters next to each other (across can mean on).
'centre of' means to look at the middle letters.
'med' becomes 'Master of Education' (synonyms).
The middle of 'masterofeducation' is 'fed'.
'ree'+'fed'='REEFED'

'put' is the link.

Can you help me to learn more?