I bet something like this would work pretty slick. Granted its over $50, but it would make this easier.
http://store.oldtowncanoe.com/produc...bb07f282f10994
Pyramid anchors work really well for holding you in place on in the river. My dad got a 40 pound one on our driftboat and we've nenver had many problems slipping in the faster current.
These smaller ones would probably work pretty well for a kayak or canoe.
http://www.cabelas.com/product/Outca...h-All+Products