By embracing life at sea, it doesn't seem as long! (4,5)
I believe the answer is:
time flies
'it doesn't seem as long' is the definition.
('time flies when you're having fun')
'by embracing life at sea' is the wordplay.
'by' becomes 'times' ('times' can mean multiplied by).
'embracing' is an insertion indicator.
'at sea' is an anagram indicator.
'life' with letters rearranged gives 'efli'.
'times' going around 'efli' is 'TIME FLIES'.
(Other definitions for time flies that I've seen before include "How quickly things move on!" , "Proverb - so life seems short" , "Limits fee (anag) - proverb" .)