We all have had the same problem at every bear away, think A mark in a good blow, many times with the same results (pitchpole).

As you turn from going upwind to downwind, you've got several additional forces all happening at once, to include the centrifical force the rig exerts as it's being swung in the big arc, the added drive from the (momentarlily, until you accelerate) greater aparant wind which is now puhsing the bows down, not lifting the windward hull up, and the added drag of going faster, on the boards which also pulls the bows down, until they get into foiling mode.

From watching that video several times, it looked like a classic bear away nose dive. As they bear away and unroll the jib, the bows go down and never really come back up...they just keep going deeper and deeper as they accelerate, until it's too deep to recover. Use full screen to see this:

http://www.youtube.com/watch?v=drgglIebuQY

On our boats, we can all run to the back, to keep the bows up when we get to A mark and we know it's coming, but they can't shift as much (relative) balast aft, as we do in that situation.

I still think it needs more volume in the bows to help prevent this nose diving. That was the cure for the early Blades, as well as some of the A cats.

You may recall years ago, when the mega cat Playstation had to have it's bows modified, enlarged, etc. The first time they took it out in big wind and waves, they also stuffed the bows and nearly pitched it right over.

The only beach cat I've felt 'safe' on in a big wind bear away was the Inter 20, and it's known for it's huge, fat bows. When I look at the design of the AC72's, I see A cat like, skinny bows. Great for keeping weight off...but not so good for preventing a picth pole.

Remember, they cannot simply 'dump the main' when it gets blowing too hard and you want to bear away, like we can. If they are going to keep going out in 25knots, they'll need bigger bows, or a much better righting system!

It looked very similar to this earlier pitchpole, on the 45' version, nearly identicle;

http://www.youtube.com/watch?v=-KNql99zT6s

Now, watch this next video of the first sail of Oracle 17. Pay particular attention to what the bows are doing, they always seem to be pointing down. Near the end of the vid. at 1:50, they are just cruising back to the dock, not pushing it, not even blowing too hard, but going downwind, and the bows are looking like they want to dive.

http://www.youtube.com/watch?v=Sr055W97l4o

Go to 'full screen' you'll have a better look.


Blade F16
#777