Cooks joints in vessels (10)
I believe the answer is:
steamships
'vessels' is the definition.
(steamship is a kind of vessel)
'cooks joints' is the wordplay.
'cooks' becomes 'steams' (steaming is a kind of cooking).
'joints' becomes 'hips' (hip is a kind of joint).
'steams'+'hips'='STEAMSHIPS'
'in' acts as a link.
(Other definitions for steamships that I've seen before include "They'll want a port" , "Vessels with funnels" .)