Glaring when fine mast is damaged (8)
I believe the answer is:
manifest
'glaring' is the definition.
(thesaurus)
'fine mast is damaged' is the wordplay.
'is damaged' indicates anagramming the letters.
'fine'+'mast'='finemast'
'finemast' anagrammed gives 'MANIFEST'.
'when' acts as a link.
(Other definitions for manifest that I've seen before include "show" , "Ship's document; plain" , "List of a ship's contents" , "Clear, obvious" , "Easily noticed - cargo list" .)