shipbuilding industry.[34] Seven of the battleships in 'Teddy' Roosevelt's 'Great White Fleet' were built here. Now one of just five U.S. yards still building deep-draft warships, NNS is the largest private employer in the state of Virginia, with some eighteen thousand workers (about half of the Cold War peak). The builder of the Ranger (CV-4-America's first carrier built from the keel up), NNS is the last U.S. shipyard capable of building big-deck nuclear carriers. Like most shipyards, NNS was originally built along a deep-channel river with inclined construction ways. Many of the original machine shops and dry docks are still in use after over a century of service. However, the facility has gradually been rebuilt into one of the most technically advanced and efficient shipyards in the world.
On the northern end of the yard you find the building area for aircraft carriers and other large ships. The centerpiece of this area is Dry Dock 12, where deep-draft ships are constructed. Almost 2,200 feet/670.6 meters long and over five stories deep, it is the largest construction dock in the Western Hemisphere. The entire area is built on landfill, with a concrete foundation supported on pilings driven through the James River silt into bedrock several hundred feet below. The concrete floor of Dry Dock 12 is particularly thick, to bear the immense weight of the ships built there. The end of the dock extends into the deep channel of the river, and is sealed off by a removable caisson (a hollow steel box). Running on tracks the length of Dry Dock 12 is a huge bridge crane, capable of lifting up to 900 tons/816.2 metric tons, while a number of smaller cranes run along the edge of the building dock. Dry Dock 12 can be split into two watertight sections by the movable caisson, so that one carrier and one or more smaller ships can be constructed at the same time.
Only a decade ago NNS could expect to start a new Nimitz-class aircraft carrier every two years or so. NNS also had a share of the twenty-nine planned Seawolf-class (SSN-21) submarines on order. There were also new classes of maritime prepositioning ships, as well as massive overhaul and modification contracts to support John Lehman's '600 Ship Navy.' But today the outlook is dramatically different, and the number of projects under way has been scaled back radically:
• With the carrier force set at twelve flattops instead of fifteen, the U.S. only needs to build a carrier about every four years.
• The Seawolf program was terminated at just three boats, and the work on all three went to the General Dynamics Electric Boat Division. Thus the massive investment in specialized facilities and tooling for submarine construction will lie unused at NNS until the start of the New Attack Submarine (NSSN) program in the early 21st century.
• Now that several hundred U.S. Naval vessels are being retired because of cost and manpower, the massive overhaul and modification program is only a fraction of what was originally planned.
NNS nevertheless remains the only American shipyard capable of building nuclear-powered surface warships. If future carriers or any of their escorts are to be nuclear-powered, then NNS will build them. Since at least one more Nimitz-class carrier is planned (the as-yet-unnamed CVN-77), the yard will stay fat in flattop construction for another decade. Meanwhile, Congress has guaranteed NNS a share of the NSSN production with Electric Boat, allowing the company to utilize its investment in submarine construction facilities built for the Seawolf program years ago. There has also been a steady flow of Navy and commercial refit and modernization work, and this is proving to be highly lucrative. In fact, NNS is preparing for one of the biggest refits ever, when USS Nimitz (CVN-68) comes back into the yard for its first nuclear refueling.
Before we actually go on board a Nimitz-class carrier, let's take a look at how the ship is built. A Nimitz-class CVN is among the largest man-made moving structures. And with a price tag around $4.2 billion, it is also among the most expensive. Only the biggest commercial supertankers are larger. Such vessels are mostly hollow space, and they aren't built to take anything like the punishment a warship must be able to absorb. On top of that, carriers must hold six thousand personnel and operate over ninety aircraft. And finally, no supertanker has a power plant of such impressive capability as the nuclear power plants on Nimitz-class-or one that requires such obsessive care. Every component of the nuclear power plant comes under the meticulous scrutiny of the Office of Naval Reactors. Very early in the history of U.S. Navy nuclear propulsion, it was realized that the first nuclear accident would mean the end of the program. Therefore, rigid inspection standards and elaborate safeguards were applied to every step of design, construction, and testing. For example, every welded pipe joint (there are thousands of them!) is X-rayed, to ensure that it has no flaws, cracks, or voids.
Strange as it may sound, building a 95,000-ton aircraft carrier is a precision operation, which requires immensely detailed planning. For example, the maximum draft of a ship being built at NNS is limited both by the size of Dry Dock 12 and by local tidal conditions. Even at an unusually high tide, Dry Dock 12 can be flooded only to a depth of about thirty-three feet/ten meters, meaning that construction of a carrier can be taken only so far before it must emerge out of the dock into the James River. Once that's done, the hull is moored to a dock on the eastern end of the yard for final construction and outfitting. Because of the quick-moving tidal conditions near the mouth of the Chesapeake Bay, the launching is normally timed to the minute, and there are never more than a few inches to spare.
A Nimitz-class CVN gets its start in Washington, D.C., about a decade before its launching, when admirals at the headquarters of the Naval Sea Systems Command (NAVSEA, formerly known as the Bureau of Ships, the agency that manages ship construction) fix the retirement date of an aging carrier. This determines the time line for budgeting a new flattop. The time line, almost a decade long, starts at the point when money begins to be committed to the building of the new ship. Soon after that, contracts are signed for 'long-lead items'-those components that can take years to order, design, manufacture, and deliver. These include nuclear reactors, turbines, shafts, elevators, and other key items that must be installed early in the construction of the ship.
Budgeting must also take into account changes and new items that go into each new carrier, for each has literally thousands of changes and improvements over earlier ships of the class. To lower the drag of the hull, the most recent Nimitz-class carriers have bulbous bow extensions below the waterline. Lowering the hull drag extends the life of the reactor cores and allows power to be diverted from propulsion to the 'hotel' systems like air-conditioning and freshwater production. Most design changes are not so significant, and usually involve nothing more than a material or component change, like a new kind of steam valve, electrical switch, or hydraulic pump. Even so, every change involves written change orders, as well as stacks of engineering drawings. Back in the 1960's and 1970's, a small army of draftsmen, engineers, and accountants was required to produce the mountain of paper documenting the changes on a new carrier. Today, a much smaller force manages a computerized drawing and change-management system custom-programmed for NNS. In fact, in the interest of efficiency and competitiveness, the entire NNS operation has become heavily computerized.
A prime example of computerization is the ordering-and-materials-control system. NNS cannot afford a huge inventory of steel plate and other materials sitting around rusting in the humid Tidewater climate. There is only limited space for storage and construction, and every bit must stay busy for NNS to turn a profit. To minimize this potential waste, NNS has installed a computerized 'just-in-time' ordering-and-materials-control system. The many components and raw materials (steel plate, coatings, etc.) that go into a Nimitz-class carrier arrive exactly when they are needed. No earlier, and no later. In this way NNS's investment capital is not needlessly tied up, and the final cost to taxpayers is reduced by millions of dollars. The NNS work-force has also become more efficient, since fewer items need to be stored, protected, hauled from place to place, and inventoried.
The actual start of construction begins some months prior to the official date of the ceremonial keel-laying. At that time, the Dry Dock 12 cofferdam is placed so that about 1,100 feet/335.3 meters of room are opened at the rear of the dock. This leaves 900 feet/274.3 meters at the river-gate end of the dock for construction of tankers or other projects. NNS workers then begin to lay out the wooden and concrete structural blocks that the carrier will be built upon. Building a ship that displaces over 95,000 tons/86,100 metric tons on wood and concrete blocks may
