Latitude of capsized small boat -- longitude coordinate ultimately pinning it? (6)
I believe the answer is:
leeway
'latitude' is the definition.
(I've seen this before)
'capsized small boat longitude coordinate ultimately pinning it?' is the wordplay.
'capsized' is a reversal indicator.
'small boat' becomes 'yawl' (yawl is a kind of small boat).
'ultimately' indicates one should take the final letters.
'pinning it?' indicates putting letters inside (inside letters 'pin' a hole in outside ones).
The final letters of 'longitude coordinate' are 'ee'.
'yawl' going around 'ee' is 'yaweel'.
'yaweel' reversed gives 'LEEWAY'.
'of' acts as a link.
(Other definitions for leeway that I've seen before include "Space for free movement" , "Elbowroom" , "Room for movement within limits" , "Amount of freedom" , "Flexibility" .)