Boat crew scoffed, we hear (5)
I believe the answer is:
eight
'boat crew' is the definition.
(crew of eight rowers)
'scoffed we hear' is the wordplay.
'scoffed' becomes 'ate' ('to scoff' is to eat).
'we hear' indicates a 'sounds like' (homophone) clue.
'ate' sounds like 'EIGHT'.
(Other definitions for eight that I've seen before include "1,001 - 993" , "Half a quarter" , "Hit, e.g. (anag.)" , "VIII" , "Chaps having row" .)