Here are a few of options for mounting your GoPro to a kayak or canoe.
1. Rear grab handle mount (Raised)
2. Boat mount
3. Paddle Mount (Using a GoPro Handle Bar Mount)
4. Helmet Mount
5. Grip Mount
6. Chest Mount
I have used at the vented helmet strap mount a couple of times and have attached it to my buoyancy aid to rig up a chest harness. The much lower filming position is pretty good. The risk of bashing the camera/head is also reduced. The video below was filmed using the chest mount position.