Gentle breeze, westerly at first, towards rear of vessel (4)
I believe the answer is:
waft
'gentle breeze' is the definition.
(I've seen this before)
'westerly at first towards rear of vessel' is the wordplay.
'at first' suggests taking the first letters.
'towards' says to put letters next to each other (I've seen this in other clues).
'rear of vessel' becomes 'aft' (I can't justify this - if you can you should believe this answer much more).
The initial letter of 'westerly' is 'w'.
'w'+'aft'='WAFT'
Can you help me to learn more?
(Other definitions for waft that I've seen before include "Float on breeze" , "scent" , "Be borne on breeze" , "Travel by air" , "Gently move" .)