vibration

[HydroTherapy]

Thanks to everybody,

I spoke to the machanic today.  He thinks the zinc could be loose.  Before I bring the boat on the 4 hour trip back to Bridgeport, CT I am having a diver go under and check things out.  I could be the best $25.00 I ever spent.  Thank you all for the advice and insight.  

David  :)

[HydroTherapy]

Thanks Ron,

I will post what the dive guy tells me tomorrow.

David

[fbien]

David -- I have exactly the same problem: harmonic vibration above 1400rpm that you can feel in the stuffing box (and even stop it by holding it). I also had the alignment checked multiple times then posted here, etc...  my gut is it's Denny's suggestion... this was also outlined in detail in one of the old tech notes. ("Shaft Align Revisited"; 1989 no 4: http://www.c34.org/mainsheet/pdf/1989_no4.pdf)

I haven't tried it yet... In San Francisco, you really don't motor much, so getting out of the harbor is fine at low rpm's.  

Let me know what you find!

thx

-fb

[HydroTherapy]

I had the diver go under the boat, and in his words there are "no smoking guns."  He said everything is in place.  I will go over the Tech Notes with the machanic for aligment of this boat.  Unfortionatly he can not see the boat till after Memorial Day.  I will use her at low RPMs.

Thanks again and I will keep you up to date.

David

[dave davis]

Thanks Frank, for your reminding me about the Post back in 1989. That's what's so great about this site. It's easy to search a subject. Sounds like between Denny's input and the 1989 post by Herb even I might give it a try.  My vibration is OK but maybe it could be better?
Frank, lets get together on this since we are in the same harbor

[fbien]

Dave, sounds good.  I've seen Wind Dragon around.  I'm in B-3 and will start doing the Fri night races as soon as my boom issue gets sorted out.

[HydroTherapy]

Another Question:

After the diver gave me the all clear I decided to check the engine in forward at the dock to see if anything released from the shaft / prop.  I brought the engine up to 2600 rpms with the boat secured at the dock and did not hear the metal harmonic sound.  I did hear/feel a rolling vibration on the wheel.  I do not know what is a normal feel of the engine  :),

David

[David...HydroTherapy]

Update:

I finally got my boat back to the yard.  They thought the engine was not aligned and said they would fix it.  After a new alignment they were still not happy, so they are hauling the boat today or tomorrow to check into some other things.

Thanks to everybody who gave me advise and insight.  Even though I am not doing the work myself, I feel I was able to communicate better with the machanic.

Thanks... David  :)

[HydroTherapy]

Another Update:

After the boat was hauled the cutless was checked.  The machanic told me there was a problem with the STRINGERS and this is causing the shaft to rub against the hull.  He said this is sometimes a problem with production boats.  

Can somebody explain to me what this means....if anything???  :)


Thank you,

David

[kss1220]

Having taken an engine in and out of a C34 over 4 times I am very familure with Stringers,Shaft Tubes, Shafts, Engine Mounts, and Alignment......To your question"What are Stringers"? The stringers are what the engine and its  mounts sit on.  I find it very hard to believe that this is the problem!  The only way that the stringers could be an issue is that somehow they were installed in the wrong location at the factory, thus not allowing enough room to allow all four engine mounts to sit properly on them.  I just realigned my engine because I replaced the engine mounts and although I had to redrill new holes for the lag bolts there was all kinds of room to accomidate the alignment.  I would really question your yard hard on this.  I find it hard to beleive the stringers have a problem.
Having said that you mentioned that the yard said that your shaft was hitting the hull.  I did have a problem with my C34 when it was new where by the log shaft tube was not installed at the factory correctly.  The old tube had to be drilled out and a new one reinstalled due to not being able to align the engine the way it needed to be without having the shaft rub against the log tube.  I had the same symptoms you describe.  Once this was done everything could then be aligned easily without any interference of the shaft and tube.  
Again I find it strange that this problem that has just come up.  In my case I always had the problem from the time it was new until it was corrected a year later.  I believe I am correct in saying that in your case you have had proper alignment and no vibration.  Therefore something has changed and I can tell you it is not the shaft tube and it is not the stringers.  Review the previous comments again as they are sound advise on proper alignment steps.  

Just my thoughts....

Kelly