Yeses at sea (4)
I believe the answer is:
ayes
'yeses at sea' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ayes that I've seen before include "Those voting for the motion" , "Votes in favour" , "The yes votes at committee meeting" , "They express assent" , "Sounds of agreement" .)