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Interesting rudder design

Does anyone know the story behind this rudder design?


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Re: Interesting rudder design

Might be a different way to provide stability when drying out. For a long time twin keels did the job but they were hindered sailing performance. They don't look deep or wide enough to give comparable stability

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Re: Interesting rudder design

I assume that this was a boat that tended to wipe out when it heeled over. The idea is that leeward side of the rudder would be more vertical and therefore the boat would be less likely to wipe out. The problem is that the other side is rotating in a direction where it would create enormous drag and cause the boat to heel more than it already is.

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Re: Interesting rudder design

Have to agree with Jeff. Current twin rudder designs try to get the windward foil out of the water when the boat heels so that it DOESN’T create drag and try to turn the boat’s bow down into the water. The pictured boat would have to heel a LOT to get the windward foil clear. It is essentially doubling the wetted surface and as Jeff suggests, still not doing a good job. Also, imagine how far over the boat would have to be heeled in order for the leeward foil to be anywhere near its most efficient “vertical” position. 30-40? Yikes! Maybe the shape helps serve as a “flopper-stopper” when the boat is at anchor, to keep it from pitching in a short sea. Might do that quite well.

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Re: Interesting rudder design

I do think that was the reasoning on doing this.

But in spite of it looking like it would be effective, you have to consider not just the blade, but the axis (or hinge) about which the blade pivots.

When heeled over such that the blade is vertical, rotating the rudder would alter the angle of that vertical blade very little with respect to the direction of travel.
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