Okay, the foils are symmetrical.  But what shape in terms of profile and cross section (cross section in specific)?

  I'm particularly interested in this because I've been thinking about counter-rotating kickup rudders on a larger proa, perhaps a 46' stretched Harry.  However, I'm not yet sure if I want to be the one to try to figure things out.  If the Speer section didn't work the way Rob liked, I imagine my first try wouldn't be the golden one.

        - Mike


tsstproa wrote:

 

asymm foil symetrical for to aft to start and connect the rudders to counter rotate. This will allow smaller aoa from each board and and better your helm control (steering of the boat) Boat will go exactly where you point it with very little helm input.

Todd

--- In harryproa@yahoogroups.com.au, "Herb" <squirebug@...> wrote:
>
> Hi Todd,
>
> Very interesting. What shapes do you recommend?
>
> Best regards
> Herb
>
> --- In harryproa@yahoogroups.com.au, "tsstproa" <bitme1234@> wrote:
> >
> > Just like your hulls so to should foils be.
> >
> > His are to pointy.
> >
> > I know what your saying at higher boat speeds your front rudder seems to be pushed through the water having no real effect. When with the just the slightest touch of the helm to steer the front rudders stalls completely.
> >
> > Try with linked boards and you will see a slight change for the better in over all stall angle and responsive steering with out stall. Try with linked boards and a better foil shape designed for the purpose and your eyes will pop out of your head in amazement....
> >
> > Todd
> >