Other ranks carrying a blade for use in a row? (3)
I believe the answer is:
oar
'blade for use in a row?' is the definition.
'other ranks carrying a' is the wordplay.
'other ranks' becomes 'or' (military abbreviation).
'carrying' indicates putting letters inside.
'or' placed around 'a' is 'OAR'.
(Other definitions for oar that I've seen before include "Bladed pole" , "One of an eight" , "Rowing boat operator" , "Use it to move a boat" , "propels floating craft" .)