Vibrations during sea trial

You or your surveyor observed this test with a dial indicator? At a few points on the shaft? Including the shaft end/tip?
And somebody verified proper set of the prop on taper? While the dial indicator was in use, check prop tip position?
But wait, there's more...
Alignment could induce a D bent or whip that needs checking also.
If it was out of the water and vibration comments were made, then this was the time to check these things and verify properly.

Slipped zinc,,, may be,,, unlikely if it was a great vibration.

So, is this the only boat for sale?

Next time, get a different surveyor.

" the shafts were turning true (by eye),"
I think that answers rcrapps question.
I'd like to have gotten more information. The zinc losening up sounds more like a result than a cause. I used to run a new Bertram with a vibration in the starboard side that we chased under warranty, but never cured.

You need to require them to cure the vibration prior to closing. Maybe it was the zinc. That's a nice theory but they need to demonstrate that it is cured on a sea trial. No different than an overheating engine.

Do they have a spare set of props that they can put on? A bent prop will do more to cause vibration than alignment.

You can waste a lot of time and money chasing phantoms and following advice from boat drivers. There are a number of possible sources that no one has mentioned such as exhaust resonance, an engine combustion issue, mounts, or some other mechanical source.

The best way to resolve this is to hire a specialist firm to perform a vibration analysis to collect data that will provide information to help isolate the source, not just the symptom.

Although not something a buyer is likely to fork out for, this sounds like good advice for an owner. I'm familiar with firms that do this work on large structures, but wasn't aware of any that do it on boats. Sounds expensive. Any recommendations?

Putting all this together it seems it had this problem during the sea trial, surveyor pointed it out, and he still bought the boat. Would seem now is the time to hire a professional to figure it out before it worsens and/or leads to more damage.

Don't think so. Sounds like they're still trying to sell it to him and are trying to excuse a problem the survey brought up. He needs to tell the seller that if it's an easy fix as they say, they should fix it and then they can talk. This could be nothing or it could be a BIG something.

Check posts for http://www.yachtforums.com/index.php?members/beauregard.43483/

http://www.yachtforums.com/index.ph...tive-maintenance-new-owner.23731/#post-205545

http://www.yachtforums.com/index.ph...tive-maintenance-new-owner.23731/#post-205550

Not from another thread. "I Just bought a 1989 (37) Silverton with (2) 454 Crusader engines with only 450 hours total. This survey concluded as few "engine must do's" I need to complete in order to preserve continued service throughout the years, and Iam looking for your feedback." I thought as you at first until Old Phart asked "Does this boat also have a bad vibration
and an obnoxious fume detector?" and he responded "Yes."

Sounds like someone needs to combine his threads.

Would help if a Senior Member were to read

all of a new member's post

in a Thread (Technical Discussion)

before adamantly replying, in error.


You seem to be enjoying some fun learning the new YF website.

Imagine how much fun someone who joined three (3) days ago

must be having; trying to learn the rules and the new YF website.


Would it prove end-of-life to you to simple post an Oops?

I re-read back to post #1 in the thread. Sorry I didn't research everything the OP has written on any YF thread. I didn't re-read your 1,284 posts before responding to you either. Sorry. There is life outside of YF to be taken care of. I'm sure the OP understands the advice. He's just in the owner's position rather than a potential buyer's. The recommendation remains the same.

All 10 posts.
Yes, that would be an exhausting task.

Great advice (recommendation).
You really believe the prior owner will fix anything, now?

Here's something of help to you earlier, if you had taken the time to read post # 171 prior to asking the Admin (post 183).

This gets very tiring.

x2

We got it already.