No were not throwing rocks at fish, this method is for hooking Trout while using a fly rod when trolling. It was first used back in the old days when you had to roll in order to troll for fish. It is called ?Stoning?.
To stone trout, an angler, usually fishing alone, trolls a nymph or a small wet fly on a long line with a long, fine leader. After the line is out, he leans the fly rod over the back of the boat and strips a few yards of extra line from the reel. Than he takes a rock about the size of a lemon and wraps the line around it several times, leaving all the slack between the reel and the stone, rather than between the stone and the stripping guide.
When the trout strikes, the stone offers enough resistance to set the hook. The line quickly peels off, however, and the slack gives you time to pick up your rod and play the fish.
Nowadays, this gives you a chance, if allowed, to use two rods. When fishing lakes in my pontoon boat, I fish along the edges of drop-offs using the stone method in the deeper water and casting a spinner bait into the shallower water.
