Rudder Vibration

My wife bought me a 1971 CM 21 for father's day. The boat has been well loved by its previous owners, but I enjoy a good project.

We got her cleaned up and took her out on Lake Washington, everything seemed to be working well, no leaks, swing keel worked etc.

Last weekend, took her out on Puget Sound and discovered that once we started to gain any speed at all, the rudder started vibrating dramatically. It was very rough and made a lot of noise. I know that this is not the original rudder, as the previous owner broke it.

Any advice as to how I can calm the vibrations down?

Welcome Keilerwhale!!

If the pintles and gudgeons are tight, not a lot of slop I can only assume the rudder is not the correct shape for your boat. Possibly the trailing edge is I not tapered enough?

All the best, Everett

http://jeanneau.proboards.com/index.cgi?board=per&action=display&thread=1297



About half way down the page is a pretty good article referenced with a couple diagrams.

I have a CM26 and our rudder vibrates a little at high speeds. I kind of like the sensation she gives back - as to say, hey I am going top speed here.

I know that my rudder is curved on one side and flattened on the other from years of sanding and re finishing unevenly. I bet yours is not balanced too. You could fix this by applying some resin and re shaping it.

Take a look at the very bottom while sighting up. See if its curving on both sides. Show us some pictures too if you can.

Thanks guys, I've determined that the gudgeons are bent to hell. I'll try to straigten and let you guys know how it goes.

How does one include photos?

Does anyone know what the correct dimensions are for the rudder of a 1971 CM21?

Keilerwhale wrote:

Thanks guys, I've determined that the gudgeons are bent to hell. I'll try to straigten and let you guys know how it goes.

How does one include photos?

https://clippermarine.forumotion.com/t18-video-on-how-to-upload-images-from-your-computer