What's stupidly loaded on to ship — it yields no profit (4,4)
I believe the answer is:
dead loss
'it yields no profit' is the definition.
(something producing no profit)
'what's stupidly loaded on to ship' is the wordplay.
'what's stupidly' indicates an anagram.
'on' says to put letters next to each other.
'to ship' becomes 'ss'.
'loaded' is an anagram of 'deadlo'.
'deadlo'+'ss'='DEAD LOSS'
(Other definitions for dead loss that I've seen before include "Dud" , "Unproductive person/thing" , "Totally useless item" , "Unproductive person or thing" , "unprofitable" .)