Sounds kind of crazy but I use a pillow case.
Seriously.
Our local lake has a rocky shoreline and is fairly shallow. I throw about twelve feet of small diameter rope and a pillow case in the hatch. Whenever and anchor is needed all I have to do is run to the bank or pick something off bottom to fill the pillow case with and tie on the rope, instant anchor.
Don't have to carry around a big heavy anchor, it's not bouncing around in the hatch beating up the boat, plus the rope comes in handy.