I'm surprised by the observation/statement that a fatter
> rounder blade shape would give more flutter. At an extreme (i.e., a
> totally round blade in cross-section), it seems that there would be no
> flutter at all). Anyway, there is a nice web page that talks a little
> about this and other theoretical and practical stuff related to Greenland
> paddles. According to the page, and similar to what Jay said, the flutter
> is due to hyraulic vortexes shedding off alternate edges of the paddle as
> the blade is dragged through the water.

Not to let this degenerate into some sort of esoteric theoretical discussion of aero/hydrodynamics....8-) I can see why a thick round shape might cause more flutter due to the vortices mentioned. Consider the ideal situation of the paddle remaining in a more or less stationary position while the boat moves....thereby not creating any vortices at all. A flatter section would be less likely to be moving relative to the water than a round one.

Does that make any sense at all????

James