[Excerpted from Casting with Lefty Kreh (Stackpole Books, Sept. 2008). The Editor.]

I discovered this cast one day on the Gallatin River in Montana. I was fishing along a cutbank where the trout were taking hoppers, and they would dart out, take the fly, and go right back under the bank. If you didn’t get your fly into that calm water right next to the bank, you didn’t get a fish. I began experimenting with different casts, and I realized that I could make a bad roll cast a good thing by using the pileup of line and leader to my advantage to help me get a longer drag-free float.

The roll dump has since become one of my favorite methods for getting a drag-free drift, especially on smaller streams where there is a slow current near the streambank but the faster water just off the bank causes the fly to drag. Once you make a few roll dump casts, you can get a feel for where to stop the rod and where the line goes so you can begin to make this cast accurately.

Once you master this cast, you can make controlled casts within inches of your target. This cast is good up to 35 or 40 feet. This is a modified roll cast where the tip of the rod on the speed-up-and-stop delivers the fly line short of the target. As long as the tip is driving down, it will stack up the front of the line and leader.

How far the fly lands from you is determined by where you direct the rod tip in front of you. If it comes down close to you, then the fly will not go far. If it still comes down toward the water, but at an angle, you can cast farther out. This cast is so effective at piling slack in your leader that sometimes you can throw into a lazy Susan and have the fly go around twice before it starts to drag.

If you have overhanging brush or other obstructions, you can’t get in there with a stack cast. The forward cast is too high. With the roll dump, the line travels much closer to the water. Some anglers worry that too much slack will make them miss strikes, but I have never found this to be a problem.

I like to use this cast instead of a stack cast if it is windy. With a stack cast, the wind can blow the line all over the place as the line drifts down. Though the roll dump doesn’t work well on quiet water because of the disturbance of the line, it works very well whenever you have any kind of moving water such as riffles.

Lefty Kreh is a longtime Fly Fisherman editor-at-large. He lives in Hunt Valley, Maryland.