Plenty of cargoes (5)
I believe the answer is:
loads
This clue is a double definition.
'plenty' is the first definition.
(I've seen this before)
'cargoes' is the second definition.
('load' can be a synonym of 'cargo')
'of' acts as a link.
(Other definitions for loads that I've seen before include "Washing jobs" , "Burdens, cargoes" , "Oodles (informal)" , "Tons, lots" , "bags" .)