To me, the term 'Slingshot' has always been a puzzle to me. It's a catchy term, but it seems to imply that the turn downwind
itself affords some sort of extra acceleration.
In reality, it is simply 'bearing away' . In less than nuclear winds it is an advantage to build speed at a closer reach before 'bearing away' as a means to build apparent wind. If you turn downwind too early going slowly, you will simply have not enough apparent wind and you will stall, or not get enough lift in the sail to maintain the best broad angle and speed. On the other hand, when the wind is really strong, one does not want to wind up too long and fast on a tight or beam reach, as the apparent wind gets too high and the rig and board are too hard to control. (As you get broader to around the 135 degrees off the wind angle, the apparent wind decreases and the power in the sail becomes more manageable) In this really strong wind situation is is best to have a short, tight-reach run-up and then bear away abruptly in a short round arc to the broad angle, to reduce the amount of apparent wind generated from reaching, as quickly as possible. In this maneuver, the acceleration is naturally, very rapid and intense.

Perhaps this is what prompted the term 'Slingshot' as I guess it feels like you are getting shot from a slingshot? But there is no magic
extra acceleration or speed gained, just more control and very rapid acceleration.
In some places this is just the only real option. A good example is the Easterly bank run at Sandy Point. In this situation you sail across the channel on a tight reach heading directly for the sandbank on the other side. The chop is large and rolling waves but you are going relatively slowly, so this is controllable. The last 15-20 meters before you get to the bank is still quite rough so you don't want to turn downwind and accelerate too far out from the bank. It is too easy to lose control and spin out in the chop. So the strategy is to wait to the last second to bear away very sharply as close as possible to the bank where the water is as flat as possible. It's a trade off between trying to build apparent wind by bearing away a bit earlier, and not getting out of control in the chop as you accelerate. The stronger the wind/gust is at that moment, the later you can leave it. The later you leave it, the flatter the water is, and the safer it is. But it is a bit like playing 'chicken'

and you don't want to stuff it up or you are going to crash on the sandbank!

. And the later you leave it in a good gust, the stronger the acceleration is. I must admit to really liking that bit.


Here is an example that a mate took of me doing this quite a few years ago. The wind is gusting around low 30's knots and I had a 41 knot 2 second if I remember correctly. Bu the time I passed the boat I was rounding up tighter and slowing down.