Are at sea in storm breaking at last (8)
I believe the answer is:
'last' is the definition.
(I've seen this before)
'are at sea in storm breaking' is the wordplay.
'at sea' indicates an anagram.
'in' means one lot of letters goes inside another.
'breaking' indicates an anagram.
'are' is an anagram of 'ear'.
'storm' anagrammed gives 'rmost'.
'ear' inserted inside 'rmost' is 'REARMOST'.
'at' is the link.
(Other definitions for rearmost that I've seen before include "farthest from the front" , "More rats (anag)" , "Fully behind" , "Furthest back" , "last" .)