For over half a century, it took four people to drive a submarine; the helmsman handled movement to either side, the planesman controlled movement up and down, and the chief of the watch (a senior petty officer) monitored the levels of water used throughout the sub to keep it balanced. Supervising all this was the diving officer of the watch, who saw that the ordered depth and direction was maintained. In the new U.S. Virginia class boats, these four men will be replaced by a pilot and copilot. Just like in an airplane. Most of the fine adjustments will be made via software, touch sensitive computer screens and a joy stick will be used for maneuvering. The navy has built a "flight simulator" for the Virginia class boats and is training the first eight "pilots" needed for that boat when it goes to sea next year. Each of the officers and senior chief petty officers under training will get at least 200 hours in the simulator before they are qualified to drive a sub.