Foils and rudders generate lift that allows the AC catamarans to fly. The further they are moved aft, the greater the lift. As simple as the principle may be, maintaining perfect control of the boat is just as difficult, as the lift required changes virtually every second. The ideal angle of the foils depends on the course, wind, speed and position of the opponents. These factors vary all the time. If the fine-tuning is not spot on, the catamaran will plunge into the water or, even worse, capsize. ORACLE TEAM USA skipper Jimmy Spithill must be incredibly sensitive and have an intelligent steering mechanism. This has been developed by BMW Motorsport engineers, who have transferred technology from motorsport to the world of competitive sailing.