Paddle convex and concave sides and forward propulsion

[fog37]

Hello everyone,

In stand up paddle boarding, the correct way to use the paddle when moving forward is to have the paddle convex side facing rearward while the paddle pushes water backward. This is explained by the fact that the paddle generates a lift force pointing backward if the convex side of the paddle is moving backward. The beginner would think that the concave side would have to face backward instead since it would seem to scoop more water..

In kayaking, I think the kayaker uses the paddle with the concave side of the paddle facing backward instead...Why?

Thanks,

 

[Bystander]

https://www.google.com/search?rlz=1...42...0i22i30k1j33i21k1j33i160k1.0.rMm4bn3QJmA ?