Slight Cavitation Problem

andy6374

Lieutenant Commander
Joined
Aug 4, 2005
Messages
1,617
This is not a persistent problem but I am having some issues with the prop cavitating.

22' Mako hull with a V6 200hp Mercury 2.5L outboard. Still playing with the setup a bit.

-Sunday I was out on the water in real choppy seas and it performed great, you wouldn't know I had any cavitation issues.

-Today it was glass, I give it some throttle...the bow rises and just as it hits around 2500 RPMs the prop cavitates and the RPMs increase. If I played with a bit I could work around the cavitation and once up on a plane it wasn't a problem. If I make a sharp turn @ WOT it will cavitate.

Some more info:
-The hub of the prop isn't spun
-The anti-ventilation plate is ~ 1/2" above the keel if not less. I'd say between even with or 1/2" above the keel.


I went to prop shop and asked there opinion. The guy told me to bring the prop back to them and he said it would add some cup to prop which should help, but that it will likely drop my RPMs just a little bit. He said that I'm right on the edge of probably having the setup perfect. He said if that doesn't work we can add some fins to the anti-ventilation plate.

And if all else fails he said we could try a SS prop with alot of rake....

And the last solution is to drop the motor a mounting hole.


What do you guys think? This guys seem very knowledgeable but so are you guys.
 

jack7771

Petty Officer 3rd Class
Joined
Jul 10, 2005
Messages
83
Re: Slight Cavitation Problem

I have a completely different boat -- dropped the motor a mounting hole and that took care of the problem. It took 2 mph off the top end, but it's worth it to me to correct the cavitation.

Jack
 

andy6374

Lieutenant Commander
Joined
Aug 4, 2005
Messages
1,617
Re: Slight Cavitation Problem

I'll go that route if necessary. Like I said, sometimes you could use the boat all day and not have one problem. But sometimes...it cavitates. It seems like I'm close to having it just right.
 

CalicoKid

Lieutenant Commander
Joined
May 27, 2002
Messages
1,599
Re: Slight Cavitation Problem

Sounds like a weight distribution issue if your performance is different from one day to the next. Are you going out with the same amount of gear/people/fuel each time?
 

andy6374

Lieutenant Commander
Joined
Aug 4, 2005
Messages
1,617
Re: Slight Cavitation Problem

Good question, but there seems to be no correlation between the engine cavitating and the amount of fuel and people on board.

Like I said the problem doesn't always present itself
 
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