Your decision left leading rowers completely immersed (2,2,3,6)
I believe the answer is:
up to the elbows
'rowers completely immersed' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'your decision left leading' is the wordplay.
I cannot really understand how this works, but
'left' could be 'l' (common abbreviation) and 'l' is present in the answer.
'leading' could be 'up' (up can mean leading in a game) and 'up' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for up to the elbows that I've seen is " very involved".)