Ship — and what one may carry leaving Cuba's capital (4)
I believe the answer is:
argo
'ship' is the definition.
(ship in Greek myth)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for argo that I've seen before include "Old boat" , "Ancient ship" , "Mythical ship" , "Famous ship" , "Agro about the constellation" .)