Race for all to see in Navy (3)
I believe the answer is:
run
'race' is the definition.
(run is a kind of race)
'for all to see in navy' is the wordplay.
'for all to see' becomes 'u' (universal dvd certificate).
'in' means one lot of letters goes inside another.
'navy' becomes 'rn' (abbreviation for Royal Navy).
'u' going into 'rn' is 'RUN'.
(Other definitions for run that I've seen before include "Unbroken series" , "Path made by animals" , "Jog; manage" , "Race, enclosure" , "Manage; function" .)