An anchor digs into the seabed. When it penetrates the surface of the sear, the suction generates resistance. The material creates resistance at the bottom of the sea and the material’s weight above. As the boat pulls the rode, it digs deeper and creates additional resistance. However, in rocky bottoms, they can’t dig in. Instead, they snag on bulges and hold insecurely. For more details about use, you can consult the user manual that comes with the product or check online sources for details.