increase or decrease prop pitch

[stsmith]

I have a 7.5 erude that was on my 12'jon boat, runs great and pushes it right along. I am now putting it on my 18' vee hull to use as a kicker. It seems to cavitate/slip at high rpm, hub is good. Should I increase or decrease the prop pitch to push the additional weight?<br /><br />Smitty

 

[ddaigle]

Re: increase or decrease prop pitch

How is the motor mounted? You may need to lower the motor down farther into the water. The lower the pitch number the more power and less boat speed. A 10 pitch is more power less speed than a 13 pitch.

 

[Solittle]

Re: increase or decrease prop pitch

Where is the cavitation plate relative to the bottom of the hull? I bet ddaigle is right & yours is way to high.

 

[walleyehed]

Re: increase or decrease prop pitch

I've got a 7.5 on mine for a kicker and you've really got to get it low to keep it from ventilating.<br />The best thing you could do is take the existing prop and have a prop-shop add some trailing edge cup-a good shop will have no problem with this.<br />It eliminated most all of my troubles, especially when turning, and then straightening the wheel.

 

[stsmith]

Re: increase or decrease prop pitch

It is about 1 inch above the bottom of the boat. Yes this may be too high. But before I spend more money getting a mount for the motor which I don't plan on keeping on the boat at all times. I'll try Walleyehed suggestion of having the prop cupped.<br /><br />Thanks Guys<br />Smitty

 

[walleyehed]

Re: increase or decrease prop pitch

Being off to one side, the 1" above the bottom isn't near low enough.<br />Cav plate on the kicker should be 1"-2" below the bottom.<br />Make sure the tilt pin is all the way fwd as well (lower unit clear in)