Prop Cavatation Problem
 

My buddy has a 1995 Envision 32' Illusion with twin 454 mags & B1s running Mirage 25s. It cavatates @ around 2800 to 3200 rpms. The problem seesm to be getting worse. He has tried adjusting trim and tabs, full load and empty boat. Props look okay with no visable signs of damage. It didn't do it when he test drove the boat but the first time out after purchase it happened and now is worse. He talked to Envision and they still use same mold for current boats so don't think it is a hull design problem. They said to check the props.
Anyone have any ideas?

Are they Mirage Props or Mirage Plus Props?

I think they are +'s but not sure. I just left him a VM asking so hopefully he'll call back soon. I suggested he call a prop specialty house such as yourself but he didn't want to take up anyones time if he wasn't going to actually purchase new props ( he is a stand up guy).

Have him call us. We don't mind answering questions. I think you may have the regular Mirage's. If you do a little cup in them will make all the difference. Have him look at the barrel of the props and it should say "Mirage" or Mirage Plus". If it doesn't say either one of those then let us know what the part number is (it should start with a 48-) and we can let you what they are.

I guess it's also a possibility the props were switched between the test drive and purchase.

Did we ever find out what the problem was here? I'm interiested. Is it a possibilbity that the props could be slipping in the hub, giving it a feeling of cavitation?

I don't think the props can slip on the hubs with out falling off. Unless all the slines were broken and then the boat wouldn't move at all.

I gave him the phone number for Throttle-Up so he is going to contact them directly. Eric from Maveric marine suggested it might be a loose gimbal. My friend is going to bring the boat up to him next week if he can't figure it out. I'll post again when I get the final results.

I know this might sound stupid, but to relieve all doubt, if the boat is slipped, has he checked to make sure nothing is hanging off the bottom of the boat, I say this because a friend had the same problem and found he had snagged a portion of a fishing net that was dragging under the boat.

The boat is trailered. Hull and drives are clean.

Update
 

Finally resolved this problem by replacing the props with 26 hydromotives spinning in. Tried them spinning out and lost a lot of mid-range. Spinning in gave it strong mid-range with good low end pull and same top end. Going to try a set of 25 Mirage plus's this weekend just to see if there is any difference. I was really suprised at the difference in spinning in vs spinning out.