Is it lee helm if...

R

RobKoci

New Member
This is all about windward heel upwind in light air again. When you've got it right, the helm sits to lee of centre about 1 1/2"to 2". There is no pressure on the helm. you can let go of the tiller and it will stay there.

Question: If that is the case, then do you have lee helm? Lee helm, as I understand it, means you have to push the tiller to lee in order to keep the boat going straight because it wants to bear off. That would, in turn, imply that, like weather helm, your rudder is acting as a break and slowing you down. That is not the case here. There is no pressure and so there is no resistance to forward motion with the helm in the position I describe here.

As an objection to sailing to windward with windward heel I have heard some say the lee helm will slow you down, so how can it be fast. That would be true if there was pressure on the helm, but there isn't. It LOOKS like lee helm, but it's not.

anyway, just thought I would throw that one out there.
 
Rob,

I thought you were trying to suppress the notion of windward heel while beating in light airs! Introducing new threads on the subject is just going to make everyone even more curious...

'Fraid I have no clue as to how to answer your question - am nowhere near experienced enough to know. And even more frustratingly have to wait until March to try it out... :mad:
 
You're right. I will start another thread under another name and call it, "Windward heel to windward -- no good!" I'll poo-poo the idea and marginalize its advocates. I'll call them fanatics, nosegays and poltrunes.
 
The reason why people say that lee helm (or weather helm) will slow you down is that the rudder causes drag when not aligned with the direction the boat is sailing. But when you are sailing upwind, the direction the boat is sailing is obviously a little below the direction the bow is pointing - there is always some leeway. If the rudder is to lee of centre by a couple of inches, it is probably aligned very closely with the true direction in which the boat is sailing, reducing drag significantly.

Of course by reducing that drag you are also reducing the lifting properties of the rudder. I'd love to see some analysis of the trade off between minimising rudder drag and maximising rudder lift.
 
The laser rudder is hinged at its forward egde, so if there is no force on the tiller, then it is not generating any side force, so it is not contributing to the boat sliding to leeward.

By healing the boat to windward you are balancing out the turning moment of boat, so you don't need to use rudder to do this. The angle of the tiller is probably a pretty close representation of the angle of attack of the centerboard, since as the boat slips to leeward, the rudder would follow that motion, resulting in the tiller moving slightly leeward.
 
The laser rudder is hinged at the front, so if there is no force on the tiller then there is no side force (leeward or windward) on the rudder, and you probably have the minimum drag configuration for the rudder.

you are using windward heel to balance the turning moment of the boat, so you don't need to use the rudder. The tiller is moving slightly to leeward because the boat still has some sidways leeward motion & the rudder is tracking this slight sideslip. The angle of the tiller might be a good indicator in this case of the angle of sideslip.
 
The sensation called "lee helm" is actually the feeling of little or no helm. People generally say that it's a bad thing because it indicates that the rudder doesn't have enough flow over it to develop enough force to pull the tiller away from you. If the rudder is stalled, generally the CB is also stalled to some degree. However, this phenomena is an exception.
 
Tony B,
FYI
There are some early Bethwaite articles indicating that 1-2 degrees weather helm may actually contribute overall to c'board and rudder combined lift (someting like main and jib dynamics in a sloop sailplan. (see Bethwaite Design archives)

Lee helm usually just creates drag (and in extreme cases can push a trapezing skiff sailor off the boat).

Not sure but in a Laser, that typically has higher weather helm characteristics than many other boats when heeled, lee helm must be exceptionally rare - in 30 years have only experienced 'virtual' lee helm just before a deathroll or when overtaking massive waves downwind when the boat was turned by nosing into the back of a crest I was overtaking.

The windward heel thing you are describing is suggested to provide upflow on the immersed foils that is capped at the hull (endplate effect) and thereby reducing tip vorticy losses (for the centreboard at least) normally dertracting from overall foil lift efficiency. Not sure this is the whole story however because the angle of incidence of the sailplan also changes in this windward heel mode and may be more efficient - and likely to be at least equivalent or greater effect.

Would be good to get some technical input on these issues.
 
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