Rudders, let's start here

This is ICON's revised rudder.

It works very well, I hand sculpted bumps onto the rudder of my old boat a Fredom 21 with a cat rig.  
It made a huge difference. When the boat would normally have fully rounded up in a puff that overloaded the rudder I was able to correct within a boat-width and maintain momentum sailing a slight S curve instead of stalling and starting over.
The bumps improve both lift and stall angle so there is no reason not to deploy them on the lenght of the rudder - and unlike a whale, a boat will always use its full lenght of the rudder in the same manner. The potential disadvantage of catching lines would have to be tested in lobster-country.
My next project is to impart some of the potential benefits on my new/old T37 which will be much harder  with a skeg in the way. 
 

It is more like a Hammerhead shark than a whale flipper - I wanted the high effeciency for the full lenght - not a pretty flipper. This was build in 2007 before these things became fashionable.
Reaserch has also been done on hammerhead sharks who use the head to stay level as they turn which is important for keeping their "sonar" trained on their prey.
http://a8.sphotos.ak.fbcdn.net/hphotos-ak-ash4/419379_3021570072504_1660...