Back to sea once more with weapons (7)
I believe the answer is:
rearmed
'weapons' is the definition.
(I have seen 'new weapons' mean 'rearmed' so perhaps 'weapons' could also mean 'rearmed')
'back to sea' is the wordplay.
'back' becomes 'rear' (something's rear is its back).
'to sea' becomes 'med' (abbreviation of Mediterranean).
'rear'+'med'='REARMED'
'once more with' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for rearmed that I've seen before include "new weapons" , "tooled up once more" .)