Strange propeller on the DeJong and Lebet website.
Click link to see full sized image............
http://www.dejongandlebet.com/949_SeaFair.htm
http://s184.photobucket.com/albums/x295/kach22i/
Reminds me of this:
http://www.thestar.com/Business/article/213475
http://peswiki.com/index.php/Directory:WhalePower_Corp#Company:_WhalePower_Corp.
Smooth (left) and scalloped (right) idealized humpback whale flipper models used for wind tunnel testing of lift, drag, efficiency, and stall behavior. While testing, only one of the models is mounted in the wind tunnel. These idealized, scale models, milled from clear polycarbonate sheet, use a NACA 0020 sectional profile (20% thick).
http://www.pratt.duke.edu/news/index.php?story=156
Patent:
http://www.wipo.int/pctdb/en/wo.jsp?wo=2006042401
