Fairly regularly holding the helm for gunners (9)
I believe the answer is:
artillery
'gunners' is the definition.
(I've seen this before)
'fairly regularly holding the helm' is the wordplay.
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
'holding' indicates putting letters inside.
'the helm' becomes 'tiller' (I've seen this before).
The alternating letters of 'fairly' are 'ary'.
'ary' placed around 'tiller' is 'ARTILLERY'.
'for' acts as a link.
(Other definitions for artillery that I've seen before include "Heavy weapons" , "Gunners" , "group of soldiers" , "Regiment" , "Large guns for use on land" .)