Rudder Lifting Foils

Here is an article from catamaran sailing on these foils now being used on many cats from beachcats to AC foilers:
http://www.catsailingnews.com/2013/02/rudder-winglets-in-racing-cats.html

 

After reading the article, it appears they could more accurately be called "pitch stabilization foils" rather than "lifting foils". Very interesting.

 

On a boat like Bradfields Osprey foiler or my new model the rudder foils will lift vertically as well as develop downforce so he and I use symmetric rudder foils.
Pitch control is exactly that-developing lift in both directions as needed.

 

I guess you are technically correct in that statement. However, in that case the normal rudder is also a lifting foil, lifting in the athwartships direction. The article explains the use of rudder foils on non foiling (airborne) craft as way of stabilizing pitch to prevent nose diving etc, rather than an addition to help lift the hulls clear of the water. Which is what people normally think of when you mention "lifting foils". Subtle but important difference. Another good application of foils!

 

Horizontal Rudder foils?

You know, after thinking about it you're right-poor choice for the thread title.
I guess the only other thing I could think of at the time was "Rudder T-foils" and I didn't feel that fit very well either.
There was a another discussion-I think under SailRocket- where one side said the SailRocket foil wasn't a hydrofoil because it created downforce and I disagreed......

 

I only bothered to make the distinction because I think its important to recognize these types of foils have other uses than the usual "upward lift" for the sole purpose of reducing displacement.

 

I think you made a good point and I agree....