Off-Topic: Rudder Design

Submitted bybt50 onSat, 07/21/2018 - 02:37

I broke my under-rudder on my surfski. I made a quick and dirty replacement and thought it was kind of fun to play with the different shapes. I've tried a couple of drastically different shapes and haven't noticed much/any difference (both had a 5/8" (the shaft diameter) + 2 layers of 6oz fg and epoxy thick leading edge). I'm kind of curious if for the next rudder if I have a more streamlined leading edge (moving the shaft to the middle of the rudder) if that would add less drag.

It would be awesome to play around with these types of change with computer modeling. Can someone suggest free software that is good for this? I've found a few computational fluid dynamics programs that seem reasonable but before I put some time into them i figured it would be worthwhile to see what others use.

Also, does anyone know any good articles on rudder shapes? 

I understand that even drastic improvements will have little overall impact but it's still fun to play with.