Prop spray question

[bassballer]

Recently ive notice that around a speed of 27-32 the prop is spraying water up onto the sides of the transom. When I drop the speed down to 18-25 it goes back to normal and shoots the wake straight back like it should. Has anyone experienced anything like this? Ive tried trimming the motor up and down but it still does it.

[MakoMike]

When was the last time you had prop reconditioned?

[bassballer]

I havent. bought the boat in august.

[Van]

The motor could be mounted too high.

The cavitation plate should be at the same height (level) as the hull when they are parallel.

That is hard to change unless you can; and want to, unbolt the engine and move it down.

If all else fails, you could add the fin on top of cav plate, they do work.

[bassballer]

ill see if i can get a pic up of the stern. i think its effecting performance and looks weird to boot.

[Billybob]

Any chance you got a chunk missing from the cav plate?

[bassballer]

stern.JPG

Not sure if you can tell by this photo. I would rather not have to move the motor at all. Might just have to live with it.

[likwid]

Originally Posted by Van

The motor could be mounted too high.

The cavitation plate should be at the same height (level) as the hull when they are parallel.

That is hard to change unless you can; and want to, unbolt the engine and move it down.

If all else fails, you could add the fin on top of cav plate, they do work.

Which is a baseline, the cav plate on a plane should be riding right at the surface of the water.

[Mr. Sandman]

It's hard to tell from that photo but it appears to me that when you lower the motor to the running position it is too deep.

You will find when you get it at the right height it will go faster and be easier to trim and control.

The "cavitation" plate really has nothing to do with cavitation...it prevents ventilation, which is the induction of air from the surface to the rotating blades just below the plate. When this happens propeller efficiency drops quickly. Cavitation is the "boiling" of water on the suction side of the blades due to the local pressure dropping below the vapor pressure. Generally this happens when you over load the blades. Ie by having too much pitch or rpm at a given speed of advance.
In any case you want see that plate just at the surface when underway. The reason why it is changing at different speeds is I bet the trim angle on the boat changes slightly.
In any case I think this winter you can adjust this so it is a non problem next year.

[bassballer]

I think it might be to deep as well. Ill be out Friday night and I'll try to take pics of it running
Posted from my iPhone/Mobile device

[thefishingfreak]

Just lean over the back when it's on plane, you should just see the top of the cav plate
Posted from my iPhone/Mobile device

[Nebe]

Originally Posted by thefishingfreak

Just lean over the back when it's on plane, you should just see the top of the cav plate
Posted from my iPhone/Mobile device

make sure your not alone when you do that...

[saltyric]

Are you positive its from the prop and not from the transducer? Just a thought, my transducer threw a brutal spray at high speeds.

[bassballer]

I thought that at first but its spraying to both sides pretty aggressively. Just didnt think that transducer could cause that type of spray.

[saltyric]

Gotcha.....Missed the part about spraying on both sides....
In that case i think what Van said makes sense.

[nightfighter]

Originally Posted by saltyric

Are you positive its from the prop and not from the transducer? Just a thought, my transducer threw a brutal spray at high speeds.

X2