While on the subject of Biomimicry hows this concept learnt from bumps (tubercles) on the *leading edge* of Humpback pectoral fins, a totally different approach from the evolution of wing, sail and fins as we know it. Interesting insight and perhaps food for thought? Looks pretty lethal though.

http://www.whalepower.com/drupal/?q=node/1
or more directly to the point www.whalepower.com/drupal/?q=node/3





Quote below from one of many links on the study;
www.ncbi.nlm.nih.gov/pubmed/7650744

"The humpback whale flipper had a cross-sectional design typical of manufactured aerodynamic foils for lift generation. The morphology and placement of leading edge tubercles suggest that they function as enhanced lift devices to control flow over the flipper and maintain lift at high angles of attack. The morphology of the humpback whale flipper suggests that it is adapted for high maneuverability associated with the whale's unique feeding behavior."

Fascinating stuff. My amateur conclusion are the bumps increases surface area.

Yup it's winter alright. Blowing S/SW maxed between 17-23knots for 2 hours and I'm working...and freakin' cold....SHUT THE DOOR you're letting in a draft
!

Well i took these 3 fins.

And made thses out of them.



The little twin fins are for my tabou twister 100, they are about 132mm tall.
The powerbox fin is now 16cm.
I chose elliptical tips this time to see if they are less dragy.
Now i just need to go and test them.