The formation of an efficient loop is the key to making any good cast. Creating an efficient loop, managing its shape, controlling its direction, and regulating its speed are the cornerstones to making a good cast regardless of the distance involved. The ideal loop has a small U- or V-shape and enough velocity so that the line is capable of unrolling smoothly without any sag or obvious shock waves in it. Although some individuals might argue that a tight loop is the trademark of a great cast, there are times when an open loop is more desirable, such as when casting weighted flies.
Loop size and shape are largely determined by the turnover (closing the gap), the stop, and the horizontal path that the rod-tip travels during the casting stroke (refer to previous Performance Fly-Casting columns for a review and more details). The shorter and quicker the turnover, the firmer the stop, and the straighter the path of the stroke, the tighter the loop will be. Oppositely, a non- or big loop will result if one or more of the following occurs: improper acceleration; lack of a firm stop or no stop at all; a slow on long turnover; and a semi-circular or severely arced casting path. By adopting the thumb-on-top grip recommended in a previous column, you can monitor the thumb tip to determine the path of your stroke and to see when the turnover occurs.
Check out the accompanying video for greater insight into this segment of Performance Fly Casting.