Just fill the bag with some potatoes. Just for a meal. Hang the net behind the boat and make sure you are going in a speed 4-5 knots so the potatoes are jumping around in the surface. If you use too many potatoes it will be hanging like a limp and nothing will happen. It’s in the jumping the potatoes scrubs against the mesh in the net. This has been done in Sweden for over 100 year. It’s a “grand mother” tip.