Nothing in boat navy finds corrupt (6)
I believe the answer is:
suborn
'corrupt' is the definition.
(suborning is a kind of corrupting)
'nothing in boat navy' is the wordplay.
'nothing' becomes 'o' (looks like zero - 0).
'in' means one lot of letters goes inside another.
'boat' becomes 'sub' (I've seen this before).
'navy' becomes 'rn' (abbreviation for Royal Navy).
'sub'+'rn'='subrn'
'o' put into 'subrn' is 'SUBORN'.
'finds' acts as a link.
(Other definitions for suborn that I've seen before include "Bribe for evil ends" , "Bribe (someone) to commit an unlawful act" , "Bribe to do wrong" , "Induce by bribery to abandon duty" , "Bribe (someone) to break law" .)