C350 Vibration Noise Survey

[bkdehuff]

Several weeks ago another member in this forum requested info from any C350 owners who have encountered significant vibration problems with their boat. Several C350 owners responded that they have this problem. The survey requested certain info, amoung which was keel type, prop type, etc. There is also a thread on this subject in the email archives.

Catalina factory management is very interested in solving this problem and would like to know the hull numbers of anyone who has a C350 with vibration problems. Catalina is currently performing a series of tests and experiments to isolate the cause. Any info we can provide may assist in this effort. I will pass along any info posted here over the next week or so.

Please respond with your hull number and any additional info you may wish to provide regarding the age and condition of your boat.

Thanks

[gpringle]

We just brought Chips Ahoy! #232 home from Huntington, L.I. to Staten Island, NY.

A rather nasty vibration set up as we passed under the Verrazano in a 3ft chop and 23kt blowing on her nose. Couldn''t make the vibe dissipate by varying rpm''s. It finally stopped when the seas settled as we turned into Great Kills Harbor.

She got a little noisy earlier in the trip when the chop picked up for awhile.

She''s Hull #232, Wing, three bladed prop, 13hrs on the 35B.

Other than this...a great trip in a beautiful boat.

george pringle

[bkdehuff]

Your vibration problem may have been the result of cavitation or some harmonic resonance due to the conditions at the time you experienced it.

With only 13 hours on your engine the vibration should not be the result of a worn cutlass bearing, which Catalina advised me is the most likely problem with some C350''s which have developed persistent vibration noise.

What happens is this. If the dripless shaft seal bellows is not properly compressed and bled of air when the boat is launched, an air pocket prevents cooling water from reaching the shaft seal as well as the cutlass bearing. This results in a very worn cutlass bearing in very short order, not to mention possible damage to the carbon graphite flange of the shaft seal. The vibration problem on my boat started after only about 60-70 hours on the engine. That was all the time it took to wear out a brand new cutlass bearing that was deprived of cooling water.

I replaced the cutlass bearing on my boat a week ago, and the vibration problem disappeared. Completely.

Catalina also has a water injection kit they can provide to obviate this problem. Make sure your newly commissioned boat does not have an air pocket in the shaft seal. In other words "burp" the shaft seal bellows if this has not already been done. This is critical.