Check out this website for tips on making your own kayak anchor using a retractable dog leash...
kayak anchor setup - Google Search
kayak fishing anchor
Poor Man's Kayak Modifications - YouTube
Good anchor idea
kayak anchor system
Simple Kayak Anchor omg! this could have so many applications
Small anchor rigged to release when stuck | Flickr - Photo Sharing!
Rigging a Basic Kayak Anchor Trolley: Episode 11
Leash attached. The leash handle attaches to the anchor trolley with float for quick release/ breakaway.