Sitting on top of the blocks makes more sense to me than the blocks being used to prevent side to side movement. So mine has shifted and come off the blocks which is probably what caused the strap to break. May have slipped off the rear blocks when I was off road. I'm going to see if I can lift it enough to slide some new blocks under the rear of the tank to at least take the pressure off the drain valve. Hope it works! Thanks for the picture, it was definitely helpful. I'm sure this has happened to others with this setup as the engineering seems a little suspect to me. Why use stubby little blocks every few feet when they could of just built supports all around the edges. The way it is now you hit one good bump with a full tank of water and there she goes off the blocks- snapped strap. Oh well, it is what it is. time to figure out an upgrade. Too bad access is so limited.