From doing some digging it's a little bit of both. The arrow whether its a hard enough blow to knock the duck dead it's certainly enough to break the fragile wing bones, so it's no longer able to fly off and easily scooped up by kayak or canoe.
From shooting, the only problem was finding the right angle to shoot to make it skip on the water. Once you got that its pretty basic, I switch the fletching to 2 goose feather,and that improved of the speed, And the stability.
But I need to do some more shooting