Weather / Lee Helm SC 17 - Help needed

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T Peterson
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Weather / Lee Helm SC 17 - Help needed

Post by T Peterson » July 7th, 2018, 5:37 am

Hi folks

We've had a good sailing week and I finally decided I had to fix this problem. I have a firm weather helm while on a starboard tack. It increases with wind speed. If we are trapezing and I release the tiller, the boat will round up quite quickly and dump our butts in the water. It's really not a big problem as I see a modest weather helm as a safety feature - this is just a little too much. I can't let go of the tiller for even a second. But, that's not my big problem.

My big problem is that while on port tack I have a neutral to occasional lee helm. I can let go of the tiller from the trapeze and the boat sails along all on its own. The bad part is that if I am trapezing, and hit a wave or gust or get lifted and need to head up, I have to push on the tiller. If I have lost my balance, or if the gust just pushed us in an odd way and made my body lean forward, I can't push on the tiller. I have tipped over as a result of this condition and don't like it.

I have had this problem for years and maybe it is getting worse or maybe I just tolerate it less. At age 66 my tolerance for a lot of things is diminishing.

The rudders appear straight and good to me. The port rudder has a little slop in it but the bottom tip only moves 1/2 inch at best. They appear to be evenly mounted. Nothing I see can explain this to me. I have set the toe-in correctly. (and toe-in being right or wrong wouldn't explain the two different helms)

I have read most of the posts on rudder issues but did not find one that addresses my particular problem.

I have a couple ideas to try:

1. Switch the rudders and see what happens
2. Measure the front tip of the rudder to the front of the boat to see if they are the same
3. Put a level on each rudder's leading edge to see if they match
3. Build up one side of one rudder with Gorilla tape to see what that does.
4. Verify that my shrouds are the same length.
5. Buy two new rudders and be done with it. (I am reluctant to do this until I know the problem is a defective rudder.)

Thanks in advance for any help and advice

T Peterson
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Re: Weather / Lee Helm SC 17 - Help needed

Post by T Peterson » July 8th, 2018, 10:57 am

More data

Both rudders have at least 1" for and aft movement at the bottom tip. The holes look pretty good but are a little elongated.

Today I switched the rudders side to side - just the rudder blanks - not the brackets.

No real difference.

Friday the helm effects were more pronounced but we had two crew, and more wind.
Today I have just me, trapezing with nice wind - but not overpowered.

Starboard tack upwind is weather helm, port tack upwind is neutral to lee helm.

My next idea/tactic is to mess with shroud length on one side and see what happens.

Mac M
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Re: Weather / Lee Helm SC 17 - Help needed

Post by Mac M » July 8th, 2018, 3:59 pm

Is the movement worse than this? https://youtu.be/5-KDpz7PJnM

This was from a 17 I had years ago that had terrible weather helm, the holes in the rudders were elongated. I filled them with thickened epoxy (structural filler) and redrilled the holes.

Tom and Matt usually say that when you have weather helm on one side and not the other the rudder may be deformed.

T Peterson
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Re: Weather / Lee Helm SC 17 - Help needed

Post by T Peterson » July 8th, 2018, 6:02 pm

The tops move a lot less than your video but the bottoms move about the same.

I don't think I have a deformed rudder because I switched the rudders and the helm stayed with the boat side and not the rudder.

Matt Haberman
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Re: Weather / Lee Helm SC 17 - Help needed

Post by Matt Haberman » July 10th, 2018, 7:20 pm

Tom,

If you consistently have weather helm on the starboard tack and it is neutral or lee helm on port tack regardless of which side the rudders are mounted on the boat then I would be 99% certain that the problem is with the rudder(s) having an asymmetrical profile. Other things like tip movement due to the pivot hole being worn out or even mis-drilled can also cause weather/lee helm issues, but the fact that the performance is very consistent and the changes you have tried thus far have no-impact tells me that it is a rudder shape issue. Assuming the problem is an asymmetrical shape there really isn't much you can do other then trying to rework the shape or replace the rudder(s). Reworking them can be done but it is pretty tough as the profile needs to essentially be a perfect mirror image (symmetrical) or you will end up with a Lee/Weather helm issue.
Matt Haberman
Aquarius Sail Inc.
http://www.aquarius-sail.com

T Peterson
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Re: Weather / Lee Helm SC 17 - Help needed

Post by T Peterson » July 16th, 2018, 5:55 am

Hi Matt and thanks for the information. Should I be able to see any asymmetry? I have looked at both rudders very carefully several times and they really do seem perfect... If I get a good day for experimenting I will try to make a temporary patch and move it around and see if I notice anything. It also seems odd to me that both rudders may be asymmetrical - but if they were built at the same time on the same molds then maybe not.

Right now I am cutting up a couple trees so my fun time is minimal :(

Matt Haberman
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Re: Weather / Lee Helm SC 17 - Help needed

Post by Matt Haberman » July 16th, 2018, 9:27 am

Tom,
You might not be able to see the asymmetry with the naked eye. It can be very subtle and in some cases only visible with a set of templates or a straight edge. The problem may only be with one rudder, or it could be with both. Assuming both rudders are original to your boat it would not surprise me if it were both. We have made a lot of changes in how the rudders are made over the years, back when your rudders were likely made they were prone to shrinkage after coming out of the mold which could cause them to become asymmetrical.
Matt Haberman
Aquarius Sail Inc.
http://www.aquarius-sail.com

T Peterson
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Posts: 38
Joined: October 14th, 2010, 1:00 am
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Re: Weather / Lee Helm SC 17 - Help needed

Post by T Peterson » August 1st, 2018, 7:17 am

Hi folks - here is an update on my rudders. I made a shim out of plastic and gorilla tape and after taping it to one side of one rudder I went sailing. No difference. Then I came back in, dried off the rudders and put it on the other side and my lee helm went from lee to neutral. Bingo. And thanks, Matt.

Then two friends came over and wanted to go out. We had about 10 mph of wind and three of us 180 lb guys. It was fun until it wasn't. While scooting along nicely, with all of us on the hull and no one trapping, the port shroud snapped right at the top of the bottom compression fitting. The mast went over in slow motion and of course the ball post now looks like an elbow...

The boat is at least 30 years old and may have the original rigging. I guess I'll be on the phone with Tom later today for two rudders and a new set of rigging. Unless someone recommends otherwise, I plan to get a new post, two new shrouds, a forestay, and bridle wires.

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