Explorer from Crown Dependency keeping a set line (8)
I believe the answer is:
magellan
'explorer from crown' is the definition.
'magellan' can be an answer for 'explorer' (Magellan is an example). I'm not certain of the 'from crown' bit.
'dependency keeping a set line' is the wordplay.
'dependency keeping' becomes 'malan' (I can't explain this - if you can you should give a lot more credence to this answer).
'a set' becomes 'gel' (both can mean to harden).
'line' indicates putting letters inside.
'malan' enclosing 'gel' is 'MAGELLAN'.
Can you help me to learn more?
(Other definitions for magellan that I've seen before include "Ferdinand -, Portuguese navigator" , "Port. navigator" , "Portuguese navigator, killed 1521" , "Portuguese navigator, died 1521" , "Portuguese navigator who crossed the Pacific" .)