Sails south to see how the land lies? (7)
I believe the answer is:
canvass
'see how the land lies?' is the definition.
(I've seen this before)
'sails south' is the wordplay.
'sails' becomes 'canvas' (I've seen this before).
'south' becomes 's' (abbreviation).
'canvas'+'s'='CANVASS'
'to' acts as a link.
(Other definitions for canvass that I've seen before include "What politician may do" , "test what way the wind blows" , "Petition" , "Solicit votes from (electors)" , "Survey people for opinions" .)