Writers have a small room with a key in a ship (7)
I believe the answer is:
scribes
'writers' is the definition.
(scribe is a kind of writer)
'key in a ship' is the wordplay.
'key' becomes 'b' (eg B major, musical key).
'in' indicates putting letters inside.
'a ship' becomes 'scries' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'b' inserted within 'scries' is 'SCRIBES'.
'have a small room with a' acts as a link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for scribes that I've seen before include "journos" , "Ancient writers (7)" , "Copyists" , "People who once made hand-written copies" .)