Karl Townsend wrote:

Sounds like you need to run a much lower pitch prop. If it is cavitating,
you are just wasting energy. Are you running it in a tunnel? Pitch?
Diameter?

I need to run lower RPM to get rid of the cavitation. I'll need a higher
pitch to still move enough water. My question is do I need a larger motor
and VFD.

Karl

I might start with the VFD. If it's cavitating I'd expect it's being
driven too fast, and slowing it down to stop the cavitation may still
give you the same flow since the cavitation isn't helping the flow.