It doesn’t seem to provide a huge amount of extra speed, but it does provide a surprising amount of height (upwind). The extreme version is the technique you often see top 470 sailors doing (especially when Rule 42 is turned off) when there they unhook from the trapeze while still hanging from their arms from the trapeze and thrust their hips up and down to aggressively flicking by pulling from the point where the trapeze connects to the mast. They do this off the start and when close to other boats or if they need more height but it is quite exhausting. Even one flick provides a small advantage: a small speed and heigh boost. I mostly posted this so that I could reference it when I am talking about the rules because ’flicking’ and ‘fanning’ is mentioned specifically in the interpretations of Rule 42. Just hitting a wave can cause the leech to flick, but hitting the wave itself often slows you down more than the flick accelerates you. But if you would hit the wave anyway better to also flick the sail. Once you get a feel for the speed and strength of the flick, it’s resonant frequency, then it is easy to accentuate the flick to get the most out of it in different moves and different conditions. According to the interpretations of Rule 42, one flick due to body movement is in the ‘yellow light area’. Repeated flicking due to body pumping (up and down in and out) is prohibited so you can’t get too carried away. On the upwind the jury looks of up-and-down and in-and-out motions of the sailor’s body. You are allowed body movement that doesn’t cause flicking, so the jury is looking for a link between the sailor’s body movements and the flicking. So going through waves you want to allow the sail to flick or cause the sail to flick, but it is illegal even in wavy conditions to flick by repeatedly moving the body up and down or in and out. Fore-aft body movement (torquing) is more legal but not completely.
What advantage does this provide? Is it like a quick pump of the sheet? What happens if this occurs while going up and down waves?
It doesn’t seem to provide a huge amount of extra speed, but it does provide a surprising amount of height (upwind). The extreme version is the technique you often see top 470 sailors doing (especially when Rule 42 is turned off) when there they unhook from the trapeze while still hanging from their arms from the trapeze and thrust their hips up and down to aggressively flicking by pulling from the point where the trapeze connects to the mast. They do this off the start and when close to other boats or if they need more height but it is quite exhausting. Even one flick provides a small advantage: a small speed and heigh boost. I mostly posted this so that I could reference it when I am talking about the rules because ’flicking’ and ‘fanning’ is mentioned specifically in the interpretations of Rule 42. Just hitting a wave can cause the leech to flick, but hitting the wave itself often slows you down more than the flick accelerates you. But if you would hit the wave anyway better to also flick the sail. Once you get a feel for the speed and strength of the flick, it’s resonant frequency, then it is easy to accentuate the flick to get the most out of it in different moves and different conditions. According to the interpretations of Rule 42, one flick due to body movement is in the ‘yellow light area’. Repeated flicking due to body pumping (up and down in and out) is prohibited so you can’t get too carried away. On the upwind the jury looks of up-and-down and in-and-out motions of the sailor’s body. You are allowed body movement that doesn’t cause flicking, so the jury is looking for a link between the sailor’s body movements and the flicking. So going through waves you want to allow the sail to flick or cause the sail to flick, but it is illegal even in wavy conditions to flick by repeatedly moving the body up and down or in and out. Fore-aft body movement (torquing) is more legal but not completely.