Sailors at home in boat going round (7)
I believe the answer is:
turning
'going round' is the definition.
'sailors at home in boat' is the wordplay.
'sailors' becomes 'RN' (abbreviation for Royal Navy).
'at home' becomes 'in' ('I'm in' can mean 'I'm at home').
'in' means one lot of letters goes inside another.
'boat' becomes 'tug' (tug is a kind of boat).
'rn'+'in'='rnin'
'rnin' inserted into 'tug' is 'TURNING'.
(Other definitions for turning that I've seen before include "Rotating; junction" , "Changing allegiance" , "Side road (from main road)" , "Side-road; (leaves) changing colour" , "Deviation" .)