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Old 05-11-2012, 17:03   #46
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Re: Paradoxical Lee Helm Puzzle

Another learning from this relates to the point someone raised about the (lifting) keel stalling.

It was a source of some surprise and joy to me that this boat was so docile (except in the OP situation) at extreme heel angles.

I think the reason might lie in two design traits. Firstly, the narrow waterline beam (which made her tippy, but wonderfully responsive, and a delight in small breezes)

Because there was not a hard turn to the bilge carried well outboard, she didn't lever her keel up towards the surface in the way boxy hulls tend to. I wonder if that makes ventilation less likely. (I'm thinking about how aerated the surface water becomes in prolonged white squalls, and how deep the trough from the bow-wave can get)

Secondly: there's that long shallow stub keel shown in the lines drawing. If the lift keel were to stall, (as high aspect ratio keels are more prone to do) the stub keel is going to maintain something closer to laminar flow, and provide some lift, and maintain a semblance of balance.

It's also potentially a fence to prevent ventilation.
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Old 05-11-2012, 17:07   #47
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Re: Paradoxical Lee Helm Puzzle

Ahh... I'd missed that it was bare-headed. That does make it all the more paradoxical...

I'm surprised the weather helm wasn't overwhelming (before the lee helm thing).
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Old 11-11-2012, 01:44   #48
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Re: Paradoxical Lee Helm Puzzle

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Originally Posted by cwyckham View Post
.....I'm surprised the weather helm wasn't overwhelming (before the lee helm thing).
Yes, I was puzzled about that too .... but I think the sacrificial topmast drag must have been partially offsetting it even at lower windspeeds.
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