Re arrangement of sails, our motto is thoroughness (6)
I believe the answer is:
rigour
'thoroughness' is the definition.
(I've seen this before)
're arrangement of sails our motto' is the wordplay.
I cannot really see how this works, but
'of' could be 'o' and 'o' is located in the answer.
'sails' could be 'rig' (I've seen this in other clues) and 'rig' is located in the answer.
The remaining letters 'ur' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'is' is the link.
Can you help me to learn more?
(Other definitions for rigour that I've seen before include "Excessive severity" , "Severity or strictness, perhaps of the law" , "Severity or stringency" , "Stiffness or strictness" , "Extreme care and thoroughness" .)