Prop Cavitation

[knotmeter]

I have read the articule from Catalina on the 350 prop cavitation. In the articule Mr Douglas address the concerns of 350 owners about momentary cavitation. On my 350, hull 148 the problem is not momentary it is constant after 1900 RPMs. The noise and vibration caused by the cavitation is severe enough that we never motor over 1900 RPMs.

In my marina there is another 2004 Catalina 350, I think its hull 154, it also has constant cavitation after 1900 RPMs. Both of our boats have had the water injection dripless packing upgrade and new cutlass bearing installed. So this problem is not just isolated to my boat. Also we sail on a small lake in Texas, so wave action and weather are not causing the cavitation.

When I contacted Mr Douglas at Catalina about my problem, he said constant cavitation like I was experiencing was not reported in their testing. And he though my problem was caused be something else.

I have had my shaft alignment checked and everything else that Mr. Douglas said could be the problem.

I did a test today. I went out and motored the boat above 1900 rpms when the noise occurs. Then I went below and put my hand on the hull between the dripless packing and the rudder post. This is where the noise and vibration where coming from. If I put my hand on the engine, transmission, shaft or dripless packing I could not feel the vibration.

Then I got the boat sailing at about 5 knots and turned on the motor. It did not make the noise or vibration at 1900 rpms or at 2500 rpm's. It just started to make a small noise at 3000 rpm's.

What this means is the prop was getting enough water not to cavitate. It also means my cutlass bearing is not making the noise.

It seems that the original 3 bade prop the boat came with cavitates.

Are any other owners having constant cavitation? If so, at what RPM?

Has everyone had their vibration / noise problem fixed?

How many owners have bought the new prop?

Michael Bourassa
Inamorata 148
Grapevine, Tx

[Triumph]

I had similar issues, the noise is not just monentary, yes, above 1900 rpm, yes, problem is fixed on my boat, with new prop. Suggest you get one. This has been throughly researched, and written about - the only solution is the new prop.