Motor height for non planing Mac 26X

Does anyone know the optimum anti-cav. plate height below the hull for my MacGregor 26X?

Most of what I read pertains to boats wanting to get up on plane, and generally advise the anti-cavitation plate to be 1 1/2 inches below the hull.

In my case the Honda 20 hp isn't powerful enough to put me up on plane, which is fine. That being the case, could I put the motor lower down. I believe I have trim set properly, but still see wash starting about 10 ft behind when running 7-8 knots.

Thanks....

 

I dont beleive cavitation plates will do anything for you except create unwanted drag with a 20hp.
Even a 50 wont really 'totally plane' a mac hull, but it will push it along more efficiently.
It would be handy to see a picture of the 'wash' you mention.
How far down is the prop from the waterline ?

 

Hi RW
The c/l of the 9.0" dia. prop looks to be about 15" below the waterline. The drop from the waterline down to the hull is approx. 5". I am thinking that if I decide to extend the prop (and rudders) back about 12" from the transom, perhaps I could also drop the prop. a bit more. No photos yet, but still working on that........Cheers

PS. I don't really care about ever getting up on plane with a puny 20hp, but just looking for the best efficiency.