Reckon old cargo has no right shape (6,2,5)
I believe the answer is:
figure of eight
'right shape' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'reckon old cargo has no' is the wordplay.
I cannot really see how this works, but
'reckon' could be 'figure' (synonyms) and 'figure' is located in the answer.
'old' could be 'o' (abbreviation as in OT - Old Testament) and 'o' is present in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for figure of eight that I've seen before include "Skater's (numerical) outline?" , "Outline traced by ice-skaters" , "Knot made at the end of a rope" , "Shape resembling two circles" , "Object or movement resembling a specific number" .)