Since I’ve been teaching kayaking, I’ve gotten quite good at ‘Hand of God’ rescues. I am only small (5’2″) and so to reach over a large creek boat is tough, but I have learned a little trick. As I reach for the upside down kayak I take my knee out and put it in the middle of my kayak …

Slipping my knee out from under the thighbrace, I push my foot off the side of my kayak. This gives me a much greater reach to stretch over the far side of the upside down kayak.
Then make sure to push one with the hand on the hull of the kayak and pull with the other.
Once you can reach the kayaker, grab their arm/drysuit/buoyancy aid and pull them back over.
Make sure to flatten out the boat fully before you let go and feel good that you’ve saved someone from a swim.