Missing from the article is any details on ventilation. You need fresh air to survive, which means non-water tight holes will be somewhere on that thing. Normally on a boat, they would be on the part that's above water. On a spinning ball, that wouldn't be an option.

My best guess is that it will be integrated in the center tube. Buoyancy ensures the center of the ball is usually above water, and one end of the tube would always be above water.