SabresfortheCup wrote:
At near 20 mph, the flow over the rudder transitions to turbulent flow within the first 3" of the blade surface, and that's in a perfect world... any surface imperfections or eddies off of the daggerboards, etc. will cause it to transition sooner. When you steer the rudder beyond it's maximum effective angle of attack (around 12 degrees) the rudder begins to stall
Interesting read for sure.
I just recently upgraded my Hobie 20 from EPO 2s to EPO 3s. At the same time, a sailing friend/competitor did the same. I drilled the holes identically when I switched the rudders.
We both found the rudder performance very different than the EPO 2 and we both needed to rake the new EPO 3s more under the boat. Helm is now 0 or slightly positive. But, the biggest thing is that I now have a hard time keeping the new rudders from loosing laminar flow when going to weather in big wind.
SabresfortheCup wrote:
thus, the rudder ventilates
Wowowowow, scary with in big seas and big wings. I find I have to turn the boat up violently to reattach......to the point of loosing the crew on the wire (Very unhappy wife).
SabresfortheCup wrote:
Basically, his sails were overpowering his rudders, so they couldn't provide enough lift to turn the boat (or at least not quickly)
OK, Now what. Depower the boat? That wouldn't make (business) sense as we were flat and driving very hard in race conditions. Wrong rudder? The boat wasn't designed with EPOs in mind. I know the surface is perfect as the EPO 3 is in new condition. What could I effect to minimize this possibility/habit?
Mast rake, different rudder rake. toe in or out........ All I can say is go sail a H20 in 20-25 and have this happen. Ohh $h!# is first response.... Hold on to your @$$ is the second.......