Water supply trouble in biggest course? (8)
I believe the answer is:
mainsail
'water' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'supply trouble in biggest course?' is the wordplay.
I cannot quite understand how this works, but
'supply' could be 'mains' (I have seen 'Supply of water' mean 'mains' so perhaps 'supply' could also mean 'mains') and 'mains' is present in the answer.
'trouble' could be 'ail' (synonyms) and 'ail' is located in the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for mainsail that I've seen before include "Central piece of rigging" , "Ship's largest canvas" , "Principal ship's canvas" , "The principal sheet on board" , "key equipment on board" .)