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Catalina/Capri 25/250 Sailor's Forums

Catalina 250 Specific Forum

Problem with lee helm

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ekremer
Deckhand

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19 Posts

Initially Posted - 06/01/2002 : 00:25:29

I have a C250 wb with 3rd generation rudder. The boat handles very well with the new rudder, but there is slight lee helm on most points of sail which occurred when changing to the new rudder. Have others experienced this, and if so, what is the fix? Too much weather helm was the problem before changing the rudder. I do not think there has been any significant change in shroud tension. Thanks for any ideas.

Ed Kremer
Ad Lib C250 WB 146

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Bill Holcomb
Admiral

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USA
769 Posts

Response Posted - 06/01/2002 : 10:08:19

Hi Ed,

I don't know for sure on a C250, but you might be able to correct the leehelm by raking the mast aft a bit. On Snickerdoodle, I tune the mast with about a 4" aft rake.

Bill Holcomb - C25 Snickerdoodle #4839

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ekremer
Deckhand

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19 Posts

Response Posted - 06/01/2002 : 16:48:32

Thanks, that was my plan, also. It will just be a little trouble to adjust the forestay inside the roller furler. I'll give it a try.

Ed Kremer

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Arlyn Stewart
Master Marine Consultant

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USA
2980 Posts

Response Posted - 06/02/2002 : 14:52:24

Ed, there is no better advice available than you get from Bill... he is a class act sailor and person...

My comments are only to add to what he suggest...and throw another possible twist to the discussion of your question which I find interesting.

While changing the rudder to the 3rd generation could have some effect on "center of lateral reistance (CLR)", I'm doubtful that the lateral resistance properties of the two are different enough to change the helm characteristics (weather/lee) very much. Of course, it greatly altered rudder torque...but thats a different issue and related to rudder balance... not boat balance.

Exploring then the possibility that boat balance hasn't changed...then what has? Here are some thoughts. Its possible that you have been sailing with lee helm all along. Wow...where is he coming from...I know weather helm when I feel it...and I've been sailing with it. Maybe... maybe not.

It could be that the rudder torque manifested itself as weather helm... but that the boat balance was lee helm. How is this possible. The answer is really quite simple and in a word is...leeway. The c250 has a bunch of it...especially the wing version. It is a high freeboard boat....with a flattish hull and carries a good bit of sail. And, if it were actually sailing balanced lee helm...that would even contribute more to leeway.

Whats leeway got to do with it? The 2nd generation rudder is high lift, large and unbalanced... meaning all of its surface was aft of the hinge line. The hydro forces of leeway would force the rudder towards a position of a weather turn when in fact, the hull itself may not have been trying to turn to weather.

When the rudder was changed to a balance rudder, those hydro forces caused by leeway were canceled... with the ability to now feel the true balance of the boat...

So, Bill's suggestion to balance the boat by moving the mast aft is a good one. What I wish to add to what Bill is saying is, what is wanted is 3-4 degrees rudder (the tiller to weather) with a feeling of slight weather helm (weather turn)on a close hauled course. This sets the boat up for optimum lift to weather and less leeway by making the rudder itself... part of the lifting surfaces...rather than it adding to leeway.

If my suspicions are true... Many C250s are being sailed with a negative angle of attack of the rudder to weather instead of positive...thus adding to leeway and poor performance up wind. Your boat going from weather helm to lee helm by just changing the rudder...indicates you were likely one of those.

My guess is that when the mast is repositioned aft a bit...and tuned so as to obtain 3-4 deg angle of attack on rudder with a slight weather helm feel... far better weathering ability will be enjoyed.

Arlyn C-250 W/B #224

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ekremer
Deckhand

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19 Posts

Response Posted - 06/02/2002 : 22:28:09

Thank you Arlyn, those are very interesting comments, that I will have to think about. I set the mast up in my driveway, let the forestay out about 5 turns, and readjusted the shrouds. Every thing looks OK. I am looking forward to testing it on the water. I will report my results.

Ed Kremer
AD LIB 250 WB/146

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The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.