Below the Fourth Deck are the heavily protected and restricted spaces dedicated to the nuclear reactors, propulsion machinery, ammunition magazines, and pump rooms. Surrounded by a double hull with massive voids (specially designed buffer zones to absorb explosions) as protection against damage, these are the safest and most secure areas of the ship. Due to the security restrictions placed upon the Navy by the Department of Energy and the Director of Naval Reactors (NAVSEA 08), I'm not able to describe their layout or equipment.[42] I can say, however, that the two Westinghouse A4W reactors provide enough saturated steam to run the ship at thirty-plus knots while leaving enough electricity to power all the ship's other systems com-fortably.The four General Electric steam turbines put out 280,000 shp to four shafts, and are highly agile at starting and stopping.
With the tour at an end, we drag our weary bones and joints up to the hangar deck, and walk over to the accommodation ladder back to the dock. By now you have a pretty good idea of the layout of today's Nimitz-class carriers. However, the four-decade production run of this design is starting to wind down, and new ideas are beginning to be put forth for a new generation of flattop. Read on, and I'll try and give you some ideas about what they will look like.
The Future: CVN-77 and CVX-78
The Nimitz-class carriers are as capable as their designers and builders could manage back in the late 1960's, representing an almost optimum mix of capabilities for operations during the Cold War. Yet SCB-102 is a design in its third decade of continuous production, the Cold War is now history, and it is time to think about a replacement after the Ronald Reagan is launched in a few years. That is exactly what the Navy is doing. The U.S. Navy will always have the mission of projecting forward presence with a regular cycle of carrier rotations. At the same time, the Navy also foresees dealing more frequently with irregular, unpredictable situations. And finally, there is the necessary requirement to keep costs of building, operating, and maintaining carriers reasonable.
Question: How can the Navy do all that?
Answer: Accept the fact that is it time for a new direction in flattop design and construction.
To do this, NNS founded a carrier "Skunk Works" called the Carrier Innovation Center, based a stone's throw from Dry Dock 12 at Newport News. Here the NNS design engineers are studying ways to build carriers that will be more suited to the operations the post-Cold War will bring. Working in concert with a number of other corporate partners, as well as NAVSEA, NNS has helped the Navy form a two-step plan for taking carrier construction and sea-based Naval aviation into the 21st century.
Phase one of the plan involves the building of one additional Nimitz-class carrier after the USS Ronald Reagan (CVN-76), which is now under construction. This unnamed carrier, known today as CVN-77, will be a Nimitz only under the skin. Current plans have CVN-77 utilizing a basic Nimitz power plant and hull structure up to the main deck level, but from there on up everything else will be new. CVN-77 will be used as a technological "bridge" ship where a number of new technologies and ideas will be tried out. While some of these technologies have yet to be fully defined, most have already been inserted into the mass of requirements documents being produced at NAVSEA. They include:
• Signature Reduction-This is stealth technology, or more accurately "low observables." Can anyone actually hide a quarter-mile-long monster from modern sensor systems? The answer is "yes," but with qualifications. You have to remember that an object's radar, thermal, electronic, and acoustic signature has very little to do with its actual size. Shaping, materials, and other engineering details have much more to do with these characteristics. By way of example, an expert I spoke with claimed that a 90 % reduction in the radar cross section of a carrier could be achieved through relatively minor, though detailed, changes to the ship's island; sponsion, and deck structures. This would mean that a Nimitz-sized ship might be given a radar signature smaller than a guided-missile frigate's. Already, outstanding signature reduction work has been done on Arleigh Burke-class (DDG-51) Aegis destroyers, which are extremely tough to see on radar and infrared sensors.
• Automation/Reduced Manning-A key Navy initiative is to reduce manning aboard ships (primarily as a cost-saving measure). With over 70 % of every defense dollar going to personnel costs, the Navy figures it can save over $50,000 per year for every sailor who can be eliminated or replaced by automation. According to current plans, CVN-77 will implement many of the "Smart Ship" systems that are being tried out on the USS Yorktown (CG-47). These systems have already reduced the size of the Yorktown's crew by 15 %. The Navy has even greater goals for CVN-77, and a cut of from 25 % to 33 % is considered possible. This could mean a reduction of up to one thousand personnel from the ship's company, and a savings of over $50 million a year over a "standard" Nimitz. That translates into some $2.5 billion during the fifty-year service life of CVN-77.
• Adaptive Mission Features-CVN-77 will be capable of rapid reconfiguration for missions other than those traditionally associated with "big deck" aircraft carriers. Operations "short-of-war" and disaster/humanitarian relief missions are becoming the rule rather than the exception. To this end, the Navy has decided to redesign the interior spaces of CVN-77 to provide more adaptability. The changes include air wing enlisted berthing areas with the kinds of personal stowage (weapons, ammunition, etc.) required by Marines or other ground personnel who might go into ground combat. Likewise, air wing planning, control, and unit spaces will be more capable for joint operations, so that units like Army helicopter battalions or special operations forces could use them with a minimum of modification. Finally, the hangar bays and elevators are being redesigned to increase aircraft options, so that tilt-rotor aircraft, UAVs, and even the planned new generation of unmanned combat aerial vehicles-UCAVs-can be carried and operated. One senior Naval analyst has even suggested the inclusion of a "Roll-On, Roll-Off" (Ro-Ro) ramp on the fantail for loading of vehicles and cargo. All of this adds up to a carrier with more capability and variety than any ever built.
• Process/Work Flow Improvements-NNS has made a formal review of the jobs done on board a carrier in order to identify key areas where "process improvements" can be implemented into the CVN-77 design. NNS is looking at what is called a flight deck "pit stop." There the crews servicing aircraft or waiting to launch could do so under shelter from the elements. Performing more flight deck functions in the hangar deck (arming, fueling, etc.) would also reduce the wear and tear on both personnel and equipment. And several tasks like ordnance loading (for very strong backs) and critical movement paths through the ship for supplies and personnel will be automated. This would eliminate the many "bucket brigades" of sailors moving supplies through the corridors. There is even some consideration of putting a "ski jump" on the bow to enhance the launching of the new generation of carrier aircraft, which might eliminate the need for catapults.
• Materials Improvements-A wide variety of new materials are being considered for inclusion in the CVN-77 design. Heat-resistant silica tiles should allow the jet blast deflectors to dispense with the traditional water-cooling system. A new lightweight blown fiber-optical local area network (LAN) cabling will increase the speed and capacity of the ship's data network by up to 100,000 times. Composites for interior and topside structures (to reduce weight) and radar-absorbing materials (RAM-to assist in signature reduction) will also make their debut on CVN-77. Hull paints and non-skid coatings with vastly expanded service lives (measured in years instead of months) are also being developed, and all of these substances will be more environmentally "friendly." Finally, with an eye to the day in the middle of the 21st Century when CVN-77 will itself go to the scrap yard, a master material list will be prepared, so that whoever takes it apart will know what to be careful with. The Navy is still having nightmares removing asbestos lagging (insulation) aboard ships built before the EPA banned the stuff. The master materials list should put an end to such problems.
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For those of you with a desire to fully understand the workings of nuclear reactors in detail, see my book