Rafters struggling across northern channel (8)
I believe the answer is:
transfer
'channel' is the definition.
(synonyms)
'rafters struggling across northern' is the wordplay.
'struggling' indicates an anagram (the letters struggle or wriggle into a new form).
'across' is an insertion indicator.
'northern' becomes 'n' (abbreviation e.g. N. Ireland).
'rafters' with letters rearranged gives 'trasfer'.
'trasfer' going around 'n' is 'TRANSFER'.
(Other definitions for transfer that I've seen before include "a side to side movement in soccer, perhaps" , "Move something from one place to another" , "Convey from one place to another" , "Hand, move, change, over" , "Convey from one surface to another" .)