I have theory on that. The hydro prop will still have a consistent load even though its not even. It would be a forward from the bottom force. Probably trying to bend the shaft up in the middle. But an uneven load from a prop that has different bite from each blade would have a different force on the shaft depending where the good biting blade was. Good blade on the bottom forces the shaft up, good blade at the left shaft forced right, good blade at the top shaft forced down, ect. I could imagine the shaft looking like a jump rope when it was under a load.
Just an opinion.
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