[amluto]

I have never believed this argument. In particular, I, and my bones, joints, etc, are approximately symmetric under left-right reflection. This means that I am not chiral, and I would expect an optimized paddle that I hold, symmetrically, in two hands, to be similarly non-chiral. (It’s a paddle, not a oar!)

More concretely, if some biomechanical factor made it a good idea to rotate the top of the left paddle forward θ degrees at the start of the left-side stroke, I would want to rotate the top of the right paddle forward θ degrees at the start of the right-side stroke. But with a feathered paddle, one of those thetas is positive and one is negative.

This is wrong in a way that used to bother me deeply whenever I kayaked. I would unfeather any unfeatherable paddle I used to restore proper symmetry.

I suppose what’s really happening is that people feather to reduce wind resistance or because that’s how they learned, and once they’ve learned it, it feels natural.

I would be willing to believe that feathering either direction is somehow biomechanically superior to not feathering at all and that the symmetry is broken arbitrarily, but I would want to see evidence :)

[colanderman]

The asymmetry is compensated thusly: when you feather your paddle, you should grip in only with your dominant hand. It should rotate freely in your non-dominant hand.

Your wrist movements can then be symmetric -- your non-dominant wrist is free to move as you please.

And because you are free to set the feather as desired -- you can set it in such a way to minimize the rotation required of your dominant hand (and, per the above, non-dominant hand) to transition from one half of the stroke to the other.