There are a number of commercial applications. Some are really expensive. You can make one yourself easily. Bolt a U shape with flanges for the bolts to your stern or off the bow. Get an 8 to 12 foot wooden dowell from Lowes, sharpen one end, and shove it through the U. Instant anchor.
I used to have a pair of Sandbar anchors that I made. They work great, but are a bit bulky to store on board. Eventually they broke from twisting into the hard pack sand that the Lake Winnebago sandbars are made of.
Here are the plans I used. If I remember right, I went with 4ft instead of 5ft to make it easier to cut out from an 8ft PVC pipe and make it easier to store on board.
