Hey Carlos,
For minikeels the endplates/anti-vortex panels on the keel bottom is a great idea. Used often in aircraft. It's actual effect is essentially doubling the aspect ratio of the wing, Prevents the upwash from rolling off the tip and maximizing the reduced wing area of the minikeel. Not helpful for a high aspect ratio daggerboard, generally just adding more form drag.
I agree some added testing would be required for the hull plate. With the shunting process the hull goes both directions, so have no idea what a plate on the fore end might do. Certainly the aft end helps pitching control, the fore end might make it worse ?
JT
--- In harryproa@yahoogroups.com.au, "carlos" <carlosproacarlos@...> wrote:
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> Have anybody tried to use an anti-vortex pannel used by Bernd Kholer in his catamaran design or by Matt Layden? designer of the minicruiser "Enigma"? - they both call it something else but in Matt's case that pannel is eliptical and I can see a good use for proas as a substitute for a central minikeel as it will not increase your draft at all. Granted, both dessigns have flat hulls that may be needed to interact with the antivortex pannel for leeway prevention. Looking at Berhn's rudders - they do not look excesively big
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> --- In harryproa@yahoogroups.com.au, Gardner Pomper <gardner@> wrote:
> >
> > I am wondering if there is a way to predict the effect of a mini-keel. In my
> > sidecar clone I am designing, my lw hull has excess bouyancy, so the draft
> > will generally be around 6" when I am not really pressing the boat hard. I
> > am willing to have up to a 2' draft, so I could potentially stick an 18"
> > mini-keel under it, if it would help the rudders.
> >
> > I could go 2 ways with that mini-keel; I could have it a high aspect ratio,
> > and have it only 6" wide, or I could go for a decent surface area, and have
> > it 3 feet wide. The smaller one would have less drag, and would break off
> > easier if hit, but would it actually help?
> >
> > - Gardner
> >
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