New rudder vibration?

[sharkwaters]

Hi Guys and I hope all had a Merry Xmas.
I need some help from the board. I have 1987 26 express, straight inboard with 240 Yanmar. The rudder shaft was galled up and I could not get it to seal anymore. I called Steve and arranged to take the boat to Mission Bay and put it on their trailer to have a new rudder installed. All went well untill the prop was drug on the ground while exiting the ramp area. Steve said they would take care of it. Steve called later in the week and said he could not get the same rudder and wanted to put a larger 1 3/8" rudder, which I approved. The boat was launched and I noticed alot of vibration on the way home, so I slowed to a crawl. It turns out that Steve tried to straighten the prop in the shop, I had a diver pull the prop and send out to AAA. After re-install, there was a vabration and cavitation noise from the rudder area at the aft lazzerette. Steve sent John down to listen and they state that it is just a new rudder noise that I will have to get used to. I'm not happy with it and looking for help. Does any one with an inboard have rudder noise or any ideas? Thanks for the help.
Bob
I had Boatswain Locker come down and check the alignment and it was .003" off and they adjusted it to .001". B.L. re-packed the shaft also; they said the packing could be wrapped around the shaft causing the vibration. The noise is more pronounced when the rudder is swung back and forth at speed.

[Time Out]

Hello Bob

Let me tell you my tail. We had the same problem we could not stop the packing from leaking. We put the boat on the trailer and dropped the rudder the post of the rudder had rusted and pitted so bad it would not seal anymore. I took the rudder to a welding shop had them build up the area with SS rod . Then took it to a shop with a very large lathe they turned it back to size its been like new for two years now no leaks no vibration no sound at all. Talking to Marc he cant remember any sound from that area ever neither can I . Marc wants to know if the new rudder is the same size as the old not the shaft but the rudder itself ?

Maybe it is larger and is to close to your prop. Did it make a noise before the work was done ?

[sharkwaters]

Russ, The original rudder was kind of a rectangle shape and the new has a strong round radius on the leading edge and is longer (top to bottom) and has more fore to aft length. The good part is that the boat turns much better, but I don't like the cavitation noise. The rudder does sit down in the prop wash now and it did not before. Steve said that this is the standard rudder that is used on the bigger boats, they cut it down to fit the boat. Thanks for the help.
Bob
The rudder is much larger, Maybe 20 - 30% larger.