Greg,

Thank you for your response. The reason I posted my original question was because I had an idea over the weekend. I thought that it had something to do with vortex sheding as well, but was having some trouble getting my thoughts to gel. Your explanation of assymetrical vortex shedding makes sense to me; thanks. Anyway, here's my idea.

The dig angle of the blade seems to be rather difficult for some to master. Even after finding it, it seems to be elusive at times (I read an article where it was compared to a baseball bat's sweet spot -- sometimes you find it, sometimes you don't). I was thinking that is because the margin of angles allowable is fairly narrow -- too little, and the blade flutters, as you pointed out (plopping and splashing), too much and it produces too little drag to efficiently move the boat. What if a thin turbulator were affixed a short distance from the edge of the blade to assist in vortex separation? It would have to be thin -- say 1/32" to 1/16" thick -- and fixed near the lower edge of the forward (bow side) blade face. It would have the effect of tripping the boundary layer on that blade edge alone, increasing the amount of vortex shedding and (hopefully) increasing the assymetry of that shedding and opening the margin of allowable blade angles a bit. Did I explain that well at all? Maybe I should try and draw a diagram to illustrate it, if not.

Just a thought, Nick

: Nick,

: The angled blade causes the vortices to shed predictably on a single side,
: which prevents flutter. In contrast, a vertical blade causes the vortices
: to shed on alternating edges of the blade which promotes flutter. The
: angled blade also has the benefit of causing the blade to bury quickly and
: catches the water very cleanly. Some folks have hypothesized that the
: angled blade helps to enhance lift (the vertical blade is often said to
: enhance drag) although I haven't seen any research to confirm or refute
: this.

: As to ergonomics, well, it is kind of a chicken-and-egg question. If you have
: a traditional West Greenland paddle that is sized to you correctly, then
: only your thumbs and forefingers encircle the paddle shaft. For most
: paddlers, holding the paddle in this manner with your wrist in a neutral
: position will automatically cause the paddle blades to tilt forward
: slightly. Many commercial paddles require all ten fingers to be placed on
: the shaft which encourages a vertical blade at the catch.

: I greatly prefer the "canted" stroke. I get a much more solid grip
: on the water and my top speed is increased. If your stroke with a
: Greenland paddle is characterized by excessive slippage then you will be
: very surprised at how the paddle "bites" using this technique,
: although it does take some practice to master. Maligiaq Padilla learned
: this technique from his Grandfather and noted that it is a common stroke
: in Greenland (although there are other methods). He referred to a stroke
: using a vertical blade at the catch as the "beginner's stroke".

: Greg Stamer