I don't use an anchor in my float tube or kick raft, but a friend of mine does. His strategy is to use a heavy nylon stuff bag attached to a nylon cord. He fills the bag with rocks at the shoreline. That way you are not packing any extra weight to and from the water. If you find you don't need an anchor, you also are not pushing the extra weight while on the water.
Wes Wada Bend, Oregon
