Useless cricketer going round old supply vessel (7)
I believe the answer is:
bumboat
'supply vessel' is the definition.
'useless cricketer going round old' is the wordplay.
'useless' becomes 'bum' (I've seen this in other clues).
'cricketer' becomes 'bat' (I've seen this before).
'going round' means one lot of letters goes inside another.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'bat' enclosing 'o' is 'boat'.
'bum'+'boat'='BUMBOAT'
(Other definitions for bumboat that I've seen before include "small boat" , "tramp steamer?" .)