Rudder Stall??

[Peter Cook]

Hi all, a funny thing happened to us on our on the lake the other day.
We we're reaching downwind in about A 15knot breeze, making about 5 knots with plenty of sea room all round.
We had 1 reef in the main and the small jib completely unfurled.
We had the dagger board down and both rudders full down and cleated.
We were heeled at about 15 degrees.

A gust came through and we heeled to about 25-30 degrees and I allowed her to round up about 45 degrees into wind ( for what reason I don't really know now - I was just experimenting I guess!).

Anyway were now close to being close hauled so I decided to turn downwind again and this when a strange thing happened.

With full rudder she wouldn't respond and remained close hauled doing about 2-3 knots. A quick check over the stern confirmed I didn't have a rudder failure so centralised and after a about 20 seconds had control back.

I can only conclude that we had stalled the rudder, has anyone else had this? Does anyone have any other ideas??
I tried to replicate this occurrence several times afterward without result so I guess the parameters for it to happen are quite critical?

I had changed the rake of the rudders recently to reduce helm steering force - could this be a factor too?

Thanks for your input.

[seahouse]

Welcome Peter –

Sounds like you are correct- and your rudder stall was a result of an unbalanced helm.

In this situation you will immediately regain rudder and directional control if you ease the main(sail) by letting the mainsheet out. (Just in case that ever happens when you are in a high-traffic area ).

I suspect that you might have been unknowingly (easy to do with wheel steering) applying excessive rudder input to counteract the boat's tendency to “weather helm”, or turn into the wind.

This is an inefficient way to sail because the rudder angle makes it act as a brake as it creates drag through the water. Also, since you are already closer to stalling the rudder, it takes less additional deflection to actually make it stall. Adjusting the rudder rake too far forward can give you a “lively” rudder feel that might be making the application of excessive rudder input invisible.

A number of things affect helm balance, some short-term while sailing (like excessive heel angle; mainsheeted in too much) and some long-term, done before hand (like mast rake). A search under “weather helm” or “lee helm” in the forums should get you some reading on the topic.

- Brian.

[Peter Cook]

Thanks Brian -will check all your suggestions.

Peter

[Steve K]

I used to do this in my X boat from time to time.

Brian explains it well.

I always had tiller boats before and again have one. I could not get the feel with the wheel steering of the x boat (partly because the steering system was old and was very stiff).

I found it pretty easy to stall the rudders on the X, even at pretty fair speeds, by going hard over too quickly, particularly when the mainsheet was hauled tight. (Another mistake I used to make was pinching the main too tight.

Good advice to ease the mainsheet when this happens

I do think it's not all operator error. I think the dual rudder design helps this to happen. It always seem to me that when the rudders were hard over, one of them would always present more of it's side to the direction of travel (acting as a brake) while the other one was trying to steer the boat. The result is that they fight each other.

When aligning the rudders, while the boat was on the trailer (I had a place on my property to do this) I could get them perfect, when straight froward. Then if I cranked the wheel all the way over, one would be turned noticeable farther than the other (I forget which one, but this depends on which way you turn the wheel) Anyway, I believe this could cause a stall situation.

One more thought; if I remembered what I just explained above and didn't ever turn the wheel completely over, I never had this problem.

Just thinking out loud

Best Breezes,
SK

[Ixneigh]

Pull the board up a bit in addition to easing the main. This will help her fall off. I have had this happen. Just get the boat moving again, and then resume course. This issue happens less with my after market rudders.
they say the Ida rudders have the ideal foil shape but my instinct is it still needs to be a bit fatter.8
Ix