Has anyone tried something like this before?  I would think having the rudders interlocked to work together this could be a gerat way to turn with wonderful rudder protection.

I AM concerned about stalling the keel to windward with the forward rudder, in which case maybe only steer with the rear in certain situations.

I’m also way in the dark about how carefully everything needs to be shaped.  foil sections for rudders or simply rounded leading/trailing edges of a flat keel section where parts rotate.

Keel one long foil with moving parts?  that would tend to send me back to just steering with the rear.

Tom

Tom,

Let me be clear about my sailing and design experience up front: I’ve sailed a snark dinghy, read a few sailing books like Gary Dierking’s, and designed an RC sailboat. That’s it. That said, here’s my view:

The snark has a completely flat dagger board. No foil shape at all, just a board. It does go to windward fine, but I’m sure it would perform better with a shaped dagger board.

Rudder vs keel % must be assessed in context of COE vs CLR. For example, on a crab claw rig which can be tilted fore or aft to adjust COE, very little or no keel is needed.

I think your idea would be more workable if you completely eliminated the center fixed section and make the remaining sections symmetrical fore and aft. Just leave the two moveable sections and their outer protective fixed sections. Otherwise, imagine the flow over the “top” of one of the rudders; it will “run into” the fixed center section and be deflected in the wrong direction, reducing rudder effectiveness and increasing drag. This would happen on the rear rudder as well unless you pivot the rudder on it’s stern end instead of it’s middle.

Great minds! 😊  Michael sketched out a similar concept a year or so ago. With his permission I’ll post it below. An intriguing idea for sure.

James,

I knew I couldn’t be the first one 😉  I guess the main difference is me trying to keep the CLR more centralized and have more intentional contact with the bottom.  lotta sand and fine gravel on the Columbia river beaches. 

One thing I’m going back and forth on is the shaft location.  My other competing option is the lead edge of the aft rudder.  I’d need a pretty bomb proof way of locking the bow rudder in line with the keel at that point.  It would aslo discourage interlocking them to help turn the long keel.  The hydrodynamics of the center shafted rudder crossing the keel are my main question.

Adam, the reasons stated above are the main reason for the “middle bit”.  Thanks for the input though.

Tom