It looks like they start out heading directly towards the camera, this could be close hauled, and then bear away about 40 degrees. Let's say they bear away to a beam reach. Those boats can well exceed the wind speed which was reported at 25 knots so let's say they got up to 25 knots. That would put the apparent wind angle around 45° but it could be farther forward. As the boat stuffs a bow it stops quickly which brings the wind angle aft. You need to dump the sheet faster than the wind angle is changing to have a positive effect. It looks like it took about 3 seconds to get to the point of no return. My guess is you just can't dump the sheet that quickly. Maybe they need a big red panic button that releases the wing from the sheet but even that may not save them.