improved and enlarged Forrestal-class vessels, they approached the upper limits of size and capability for oil-fueled carriers. The time had come for a break with fossil-fueled power plants, and the carrier that followed was truly revolutionary.
The successful development of nuclear reactors to propel submarines encouraged the Navy to put them in surface ships. Backed by the mercurial Director of Naval Reactors, Vice Admiral Hyman Rickover, an improved Kitty Hawk design was developed to accommodate a nuclear propulsion plant. Ever eager to maximize the influence of nuclear power in the Navy, Admiral Rickover dictated that the new carrier should have just as many nuclear reactors (eight!) as there were oil-fired boilers in each Kitty Hawk-class carrier. When the new carrier, designated USS Enterprise (CVAN-65), was commissioned in the early 1960's, she was so overpowered that the structure of the ship could not stand the pounding of a full-power run. There are stories of speed runs off the Virginia capes in which the Enterprise went so fast (some say over forty knots; the actual numbers are still classified), that she left her destroyer escorts far behind, without tapping her full power.
Though Enterprise more than lived up to the heritage of her proud name, she was to be a one-of-a-kind ship. Then-Secretary of Defense Robert S. MacNamara, no friend of the Navy, blocked construction of more nuclear-powered carriers. Over the next decade, only two new carriers, America (CVA-66) and John F. Kennedy (CVA-67), would be constructed. These flattops, essentially repeats of the earlier Kitty Hawk-class, were powered by oil-fired boilers. After MacNamara's resignation in 1968, the ban on nuclear carrier construction lifted, and the Navy received authorization for a new class of three nuclear-powered attack carriers. This would become the mighty Nimitz-class (CVN-68) program.
A side view of an improved Nimitz-Class (CVN-68) nuclear-powered aircraft carrier. JACK RYAN ENTERPRISES, LTD., BY LAURA DENINNO The Nimitz-Class (CVN-68) Supercarriers
Because of the vast base of experience developed over the previous four decades, even before design of the Nimitz-class carriers began in the late 1960's, the Naval Sea Systems Command (NAVSEA) had a number of good ideas about what they wanted from their next generation of flattops. Frankly, they wanted a lot! The largest warships (in dimensions and displacement) ever planned at the time, the Nimitz-class carriers were to be the ultimate expression of sea-based airpower. Some of the 'fighting' qualities of the Nimitz-class included:
• Aircraft Capacity-For over seventy-five years the value of a flattop has been measured by the number and types of aircraft it can carry. Ever since the Navy learned that the original USS Ranger was too small to carry a credible air wing, U.S. carrier designs have emphasized big flight and hangar decks to park, stow, and operate aircraft.[28] In addition, growth in the size and weight of combat aircraft has driven the design of carriers. For example, an F4F Wildcat fighter of 1941 left the deck at a maximum weight of 7,952 lb/3,607 kg, but today's F-14 Tomcat fighter has a maximum takeoff weight of 74,348 lb/33,724 kg! The Nimitz-class carriers were designed to handle ninety or more aircraft (though they currently operate with air groups of about seventy-five), depending on 'spot factor' (the amount of deck space each aircraft type requires).
• Armament-Experience with heavy guns and long-range surface-to-air missile (SAM) batteries on earlier classes of aircraft carriers proved that the deck space, interior volume, manpower demands, and blast effects of such weapons interfered with air operations, the carrier's true reason for existence. Therefore, weapons on newer carriers would be limited to point defense (i.e., 'last ditch' self-defense) systems like the RIM-7 Sea Sparrow surface-to-air missile (SAM) and Mk. 15 Phalanx/CIWS 20mm automatic cannon. A few.50-caliber machine guns would also be mounted for defense against suicide motor boats or terrorist swimmers.
• Crew Size-For centuries, experience has shown that the more sailors you cram aboard a warship, the better her fighting qualities, especially when you need to repair battle damage. On the other hand, sailors take up a lot of space, and generate large 'hotel' loads on the ship's power plant (for electricity, water, heating, and cooling) that have nothing to do with fighting. Modern sailors are volunteers, who expect a minimum level of comfort. The Royal Navy's eighteen-inch spacing between hammocks aboard warships two centuries ago may have worked for impressed seamen, but would hardly do for today's sailors. Therefore, naval designers are constantly balancing the advantages of larger crews with the costs of personnel on ship size and capability. The Nimitz-class carriers would be designed to sail with about six thousand personnel on board: 155 officers and 2,980 sailors for the ship; 365 officers and 2,500 enlisted personnel for the air wing. Now add an admiral's staff, a few dozen civilian contractors to maintain the high-tech equipment, and a constant trickle of distinguished visitors and media representatives, and a carrier can get really crowded!
• Deployability-Since a crisis may be halfway around the world, a carrier needs to go fast. On the other hand, high speed is worthless if the carrier does not carry sufficient fuel to get where it has to go without frequent refueling. The interior space consumed by a large power plant and its fuel is not available for aircraft, crew berthing, ammunition, jet fuel, and other useful stowage. In the final analysis, the choice of a nuclear power plant was a no-brainer. The Nimitz-class carriers were designed to carry two General Electric A4W/A1G nuclear reactors, and were expected to operate for fifteen years between refuelings.[29] That's up to one million nautical miles of steaming on just one set of reactor cores.
The carrier USS George Washington (CVN-73) conducting an underway replenishment (UNREP) from the fleet logistics ship USS Seattle (AOE-3). UNREP is a vital capability in keeping battle groups forward-deployed, and utilizes both 'high lines' and helicopters to transfer cargo and fuel. OFFICIAL U.S. NAVY PHOTO • Sustainability-Once a carrier has reached an operating area, it must conduct operations for as long as possible without resupply since it may take weeks for fleet supply vessels to catch up with the carrier battle group. The enemy may not wait while you replenish at sea, so the amount of fuel, food, ammunition, and spare parts carried on board has a direct effect on how long a carrier can stay in action. It is also essential when fleet supply vessels reach the carriers; for when carriers are conducting Underway Replenishment (UNREP), basic safety rules dictate that they cannot operate aircraft or maneuver freely. Thus, the less often they take aboard fuel and supplies, the more time they can spend 'on the line' conducting combat operations. The Nimitz-class carriers were designed to store up to nine thousand tons of jet fuel and almost two thousand tons of bombs, ammunition, and missiles. This is a vast improvement over earlier designs.
• Survivability-All of the above are worthless if the carrier is a blazing hulk about to turn turtle and sink. Nimitz-class carriers were designed in an era when the threat of Soviet cruise missiles and torpedoes armed with 1,000-kg/2,200-lb warheads was quite real. These weapons could blow a cruiser or destroyer in half, and do considerable harm to an aircraft carrier. The Navy was especially conscious of these dangers after three deadly fires aboard USN carriers during the Vietnam War had taken a high toll of lives, aircraft, and equipment. Remember that these ships are basically big boxes filled with explosives, jet fuel, and people, all packed tightly together. With all this in mind, the NAVSEA designers went to extreme lengths to make the new carriers both durable and survivable. The flight and hangar decks, as well as the hull, would be built from high-tensile steel, with a vast scheme of compartmentation and built-up structure. In addition, the new flattop would make only minimal use of light metals like aluminum, which are flammable under some easily reached fire conditions.
