Enter the best way to rig your decoys out there.  The Ace Decoy Anchor system.  The simplicity of this system along with the fact that it attaches below the water line is what makes it so great.  The premise is that the anchor itself is shaped like a hook to attach to the keel of the decoy.  This allows for the achor to hold tight, but not effect the look of your decoys.  A rubber band allows you to stretch them tight for superior stability during transport.  This is by far the best way I have seen to rig decoys.  Check them out and see for yourself.  Cabelas has a great supply of both the regular and large varieties of these anchors.