Rudder Shudder

[A. Jones]

I am thinking of buying a 1978 Catalina 30 but am concerned about a light shuddering sound that comes from the rudder. The current owner said it also concerned him when he bought it and that it was not really a problem. Has anyone out there experienced a similar problem and corrected it?Also, the depth meter shoots out a wild range of numbers, and I wonder if anyone knows why.

 

[Dave Ullrich]

Vibrating Rudder

Sounds like the bearing has gone south. It eventually could cause some pretty big problems from what I've heard in the past. But I'm NOT an expert. The depth-sounder could have a couple of problems:1. It's fowled.2. The transducer is shot (happended to mine during a long haulout).3. Wiring coroded, not making a good ground.

 

[R. Palaia]

When does the shuddering happen..

when sailing or motoring???Roc

 

[Scott may]

Depth sounder

You may want to check the gain on your sounder. If the bottom is soft you will get eratic readings. Hard bottoms give the best readings. If the bottom is soft turn up your gain. If its hard turn it down. Also, some sounders with jump around when you are traveling through turbulent water ( it can be turbulent under the surface and not show on the surface) or if there is a large difference in the thermocline in the water. Just some things to check. Also air under the bottom of the boat will also give bad readings.(boat wakes, or high chop can cause this)

 

[A. Jones]

Shudder happens when

When I was on the boat there was no wind, so it only happened when we were motoring. I don't know if it happenswhen we were sailing. It did not make the noise after we settled on a course.

 

[Rob Rich]

Shudder

I have a shudder on my C-27, but it is a shudder that you feel, not hear. It occurrs at higher speed, and is due to excessive marine growth on the surface of the rudder. I plan to have a bottom job soon and have it removed.My surveyor also mentioned that (after the bottom job) shaving the trailing edge of the rudder into a flat plane (imagine the back end of the trailer on a tractor-trailor) will help eliminate the shudder. I would check on that with the yard first, though. Best of Luck,Rob Rich

 

[R. Palaia]

If it's motoring, could be prop wash

You say that it's only when motoring. I have a C34mkII, and when turing hard to port or starboard, I hear what sounds like a helicoptor overhead. As soon as the rudder straightens out, it goes away. I asked Gerry Douglas of Catalina about this and he said it was normal prop wash. So I haven't thought much about it since. It's only when making a tight turn. It doesn't happen when the rudder is straight or during wide turns.Roc