How far in the water should my trolling prop be?

I have a 12V 46lb MotorGuide on my 16ft Lowe 160W.

Yesterday I raised to just below the surface while running in submerged tree infested water.

Where should it be in open water?

My suggestion would be to keep the prop at least 6" below the surface. If not, It should be low enough so it does not suck air.

It depends on what type of water you are fishing.

If your in water with trees, like you where you did it right. Keep the motor up so it doesn't hit.

I try to keep it as shallow as I can without it sucking in air at the speed I am running. If I hit it on high I will suck air, but at the speed I am moving around it doesn't suck air, that that is good for me.

If I am fish rough water and the motor is coming out of the water, I'll put it as deep as I can.

If I am fishing shallow I'll run it as shallow as I can.

If I am fishing weeds, I'll keep it up shallow too. don't want it digging in the weeds.