This is primarily a dry fly cast. It is also called a "wiggle" or a "serpentine"cast. Like several other cast, it puts slack line on the water and this gives you a longer drag free drift over a rising fish. It is very good when you have variable currents between you and the fish.This is a pretty easy cast to learn.

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The Serpentine Cast - Orvis, Pete Kutzer (YouTube)

The Wiggle Cast - Bumcast (YouTube)