Right on the bay, but concealed (6)
I believe the answer is:
covert
'concealed' is the definition.
('covert' can be similar in meaning to 'concealed')
'right on the bay' is the wordplay.
'right' becomes 'rt'.
'on' means one lot of letters go next to another.
'the bay' becomes 'cove' (I've seen this before).
'rt' after 'cove' is 'COVERT'.
'but' acts as a link.
(Other definitions for covert that I've seen before include "Concealed - vector (anag)" , "Not openly displayed" , "Not open; thicket" , "Not acknowledged" , "Hidden - thicket" .)