Interior space in nuclear submarines is roughly twice as large as conventional subs. In the interests of morale, such submarine innovations as juke boxes, ice cream makers, motion pictures and well-equipped libraries have been added to the recreational facilities. A qualified doctor is also carried by each atomic sub but the first four years of operation have shown that his main function is not radiation protection but atmosphere control, the vital art of circulating fresh oxygen within the submarine's pressure hull. Nuclear submarines dive and surface by the conventional method, taking on and discharging quantities of water, the ship's most readily obtainable ballast. Diving planes, located both at the front or bow of the ship and the rear or stern, regulate the angles of descent and ascent ordered by the commanding officer.
Modern submarines can fully submerge in less than a minute.
Speeds and maximum operating depths have also improved markedly with the advent of nuclear power. This is approximately three times faster than any World War II sub could do for one hour's duration. The George Washington, unlike the Nautilus, Seawolf, or Skate, has a revolutionary hull form to combine with its atomic engine. The early nuclear subs were operated primarily for testing their propulsion plants and, with overwhelmingly successful results the Navy and General Dynamics turned to the task of giving the new source of power a streamlined vessel to push. The solution was a shark-shaped hull with one large propeller to do the work of two small ones.