Like what Rob said. Keep them vertical while sailing at optimal speed range. Canting only if your trying to create negative or positive lift. Sweeping rudders fore or aft to me is to much of a hassle. changes flow over boards and forces felt in tiller. The less you have to deal with the better.
Symmetrical vs Asymm. Asymm will bite sooner and harder grippier more lift more drag. Symmetrical run free'er and not so forgiving to aoa changes less bite less lift less drag ,better at higher flow rates.
That's just the general notion.
There's alot more to it than What I'm capable of explaining correctly.
I'm thinking a more toned done asymm foil now. Just to see where it goes from there. 6%/12%, 5%/10% balanced proportions instead of my 0%/10%
Todd
--- In harryproa@yahoogroups.com.au, Gardner Pomper <gardner@...> wrote:
>
> Rudders continue to be my main concern on the harrys. I am enamored of the
> asymmetrical setup that Todd has demonstrated on his proa daysailer, but I
> am also concerned about the instability issues that theory seems to predict
> on the rudders (from Tom Speer and others).
>
> My question is what effect it would have to cant the rudder a small amount,
> while keeping the axis of rotation vertical. Does this effect the stability
> at all (plus or minus)? How would it effect the lift? I don't seem to be
> able to come up with a thought experiment that would give me a clue about
> what effect, if any, this would have. Does anyone know something that would
> help predict this?
>
> - Gardner
>