Casting Heavy Flies can be a difficult and dangerous activity with the risk of embedding a hook in the back of your head ever looming.
The key to casting big flies, then is to slow everything down, widen your loops, and avoid sudden changes in direction. To accomplish all these, you need to learn the Belgian cast (also called the oval cast). Rather than moving the fly back and forth along a two-dimensional plane, the Belgian cast keeps the fly moving at all times through a three-dimensional pattern. This means that there are no shocking stops, extra slack, or dropping fly.
To perform the Belgian cast, you make a sidearm backcast and then a forward cast over the top, with a nice, wide loop. The name oval cast comes from the fact that, if viewed from above, your rod tip describes an oval, rather than a straight line. When you are making the Belgian cast, line speed is not important, but you must keep the line moving at all times to keep the fly from dropping.
For a complete lesson on the Belgian cast, check out Macauley Lord’s excellent article on Midcurrent.
Copied from Midcurrents Techniques. See more at http://midcurrent.com/experts/casting-heavy-flies/.