Там есть аккумуляторы. На видео постоянно мелькает строчка о давлении в аккумуляторах. Там либо пневматика, либо гидравлика.

Но это не так важно с точки зрения обсуждаемой темы.

Вот, нашёл:

About those control systems, what can you share?
This time around we are allowed specifically for appendage rake, so we can use more-modern control systems where we can measure a position. The helmsman sets a command that he wants the board at “X,” and we have a displacement transducer or whatever that measures the board position and a little computer that says the board is currently at X, plus or minus whatever. We can get very fast time-to-targets, and then we can have the computer drive the board to that target. In San Francisco, we were pressing a button that said open the valve for .03 of a second and see what happens. The problem is that if you do that at 20 knots, it’s a different result than at 40 knots, so the boats were hard to sail because of that. We are in the modern world of control systems, but we’re a still a long way away. It’s been a fun science project. But one of the things that is making our lives easier is that we now have hydraulic accumulators: nitrogen-charged gas chambers that we can pump up to the relative pressure of a dive tank. When you see the guys winding the handles, a lot of what they’re doing is recharging the accumulators. We are using hydraulic power from those accumulators to control rake, boards up and down, and many other things.

The other advantage of working through an accumulator is that it can deliver about 400 watts over a sustained period of time. If you have a guy winding the handles, you can have oil delivered at 400 watts, which is many cubic centimeters per minute at any given pressure. If he’s pre-done all that work and put it into the accumulator, you can open a valve and instantaneously have much higher pressure coming out, so you can move boards much faster than operating them directly from the pump.

https://www.sailingworld.com/tech-behind-americas-cup/