One carrying spare tyre may be finished with boat crew (10)
I believe the answer is:
overweight
'one carrying spare tyre' is the definition.
(spare tyre can informally mean stomach fat)
'finished with boat crew' is the wordplay.
'finished' becomes 'over' (similar in meaning).
'with' becomes 'w' (abbreviation).
'boat crew' becomes 'eight' (I've seen this before).
'over'+'w'+'eight'='OVERWEIGHT'
'may be' acts as a link.
(Other definitions for overweight that I've seen before include "Big" , "Too heavy" , "Carrying a lot of stones" , "stout" , "Obese" .)