If getting back into port, somehow, there's an advantage (6)
I believe the answer is:
profit
'there's an advantage' is the definition.
(profit is a kind of advantage)
'if getting back into port somehow' is the wordplay.
'getting back' is a reversal indicator.
'into' is an insertion indicator.
'somehow' indicates anagramming the letters.
'if' back-to-front is 'fi'.
'port' anagrammed gives 'prot'.
'fi' going within 'prot' is 'PROFIT'.
(Other definitions for profit that I've seen before include "Gain, return on investment" , "bonus" , "Clean up" , "returns" , "Yield - gain" .)