Happy turning barge right, one managed easily (8)
I believe the answer is:
pushover
'happy turning barge right one managed easily' is the definition.
I can't tell whether this defines the answer.
'happy turning barge right one' is the wordplay.
'happy' becomes 'up' (I've seen this in other clues).
'turning' says the letters should be written backwards.
'barge' becomes 'shove' (I've seen this before).
'right one' becomes 'r' (I can't explain this - if you can you should give a lot more credence to this answer).
'up' in reverse letter order is 'pu'.
'pu'+'shove'+'r'='PUSHOVER'
Can you help me to learn more?
(Other definitions for pushover that I've seen before include "Topple - easy opponent" , "upset" , "breeze" , "customer offering little resistance" , "Child's play, piece of cake" .)