by Guy Gugliotta / Washington Post –
(February 8, 2004) — The ship model started from the corner of a man-made grotto, pitching and yawing spectacularly through heaving mounds of black water designed to mimic the most terrible storm ever to hit the mainland United States.
“It doesn’t look like much from here,” said naval architect Arthur M. Reed as the little ship motored across the test pond at the David Taylor Model Basin. “But if you were small enough to stand on the deck of the model, some of those waves would be the equivalent of 60 feet high. Here we have immortalized Hurricane Camille.”
With its backward-canted bow, its inward-angled hull and its pillbox superstructure, the project the Navy calls DD(X) bears scant resemblance to any surface warship any modern sailor has ever seen. But this new destroyer — or something equally radical — is likely to become the template for a new generation of vessels that will embody the most dramatic changes in U.S. warship design since the advent of nuclear power. The Navy expects the highly automated vessel, with its radical engineering systems, to operate much more cheaply and efficiently than anything in today’s fleet.
After nearly 13 years of conceptual studies and design work, the Navy in the next few months is scheduled to pick DD(X)’s basic hull design — a revolutionary inward-slanted “tumblehome” shape built to deflect enemy radar and give the ship the same electronic “signature” as a fishing boat. The model being tested is one of the competing designs.
The ship must be able to endure “sea state 8,” a Camille-size hurricane, and much more. Anticipating increased use of expeditionary forces in the 21st century, the Navy wanted a vessel capable of maneuvering in restricted waters to provide gunfire and missile support for troops as far as 100 miles inland.
DD(X) will be electric-powered. Much of its superstructure will be made of graphite composite instead of steel or aluminum. It will be a “stealth ship” with the Navy’s first-ever onboard control system for dispersing heat emissions and with its radars embedded in the skin of the ship to make detection by enemy radar more difficult.
Instead of the 350 officers and enlisted men and women aboard destroyers, the DD(X) will sail with a crew of 150, or fewer, because of automation. It also will have 80 missile launchers and two main deck guns whose 155mm ammunition will be loaded, moved, stored and fired without ever being touched by human hands.
DD(X)’s tumblehome hull will curve slightly inward from the waterline or even below, instead of flaring outward, as traditional hulls do. But while the new shape will make it more difficult for enemies to get a solid fix on the ship, the tumblehome design is also much less stable. Making it work properly is “very tricky,” said naval architect Barry I. Fox. “It’s the most difficult ship I’ve ever worked on.”
But worth it, for those concerned. “You only get an opportunity once in a generation to do something like this,” said Navy Capt. Chuck Goddard, the Naval Sea Systems Command’s project manager for DD(X). “It’s pretty exciting.”
The Navy began the program in late 2001 after 10 years of research and scrapping an earlier, more elaborate design that Chief of Naval Operations Vernon Clark said at the time carried “too much risk” of failing to deliver what the Navy wants. Goddard said in a recent interview that the early design was “unaffordable.”
By contrast, DD(X) is supposed to provide the Navy with a new generation of warship technology good for as many as 40 years. The prototype may be a destroyer, but the design will likely be adapted for cruisers and possibly other ships.
Goddard said 24 DD(X) destroyers should enter the fleet beginning in 2013. The price for each would be between $1.2 billion and $1.4 billion, with the first one likely to cost twice as much, he added.
The program is not without critics. The Congressional Research Service issued a report in October suggesting that lawmakers examine whether the Navy needs a radical new generation of ships when it might be able to fill its needs in different — and cheaper — ways.
“We need it for fire support,” Goddard said. “You can leave your howitzers at home — for the first 100 miles [inland] this ship will provide support 24/7. It’s designed to fight in really difficult water.” At 600 feet in length, DD(X) will be 100 feet longer than current destroyers, but its 28-foot draft will be 3 feet less than today’s ships, a critical margin of difference for a ship operating in restricted waters.
Some critics have also focused on the reduced crew size, suggesting that DD(X) will not have enough people to cope with a collision or an attack such as the terrorist bomb that tore a hole in the side of the destroyer USS Cole in 2000 in Yemen.
“And if you reduce the crew below 100, you might even have to worry about pirates,” said defense analyst Norman Friedman, a historian of U.S. warship design. “The Navy likes to have human insurance against things going wrong.”
Finally, said William D. O’Neil, chief scientist at the Center for Naval Analyses, the Navy needs to make certain it is not trying to travel in too many new directions at once. “None of these things strikes me as terribly risky — not like going to nuclear power,” O’Neil said. “But they need to ask whether all these technologies should be in Navy ships at this time.”
Goddard said the Navy will let the basic shipbuilding contract for DD(X) in 2005. Northrop Grumman in 2002 won a $2.9 billion contract to design the ship’s new systems and provide the blueprints for the builder.
Every aspect of DD(X)’s design has something new, but nothing has proved more challenging than the tumblehome hull. The rounder the hull, the more unstable it becomes, said Reed, the Navy’s lead hull designer for DD(X) at the Carderock Division of the Naval Surface Warfare Center in west Bethesda, where the model basin is located. “We designed a couple of hulls and found they capsized quite a lot.”
As part of the solution, designers extended the tumblehome below the waterline and added 28 feet of extra freeboard — the height of the deck above the waterline — so the ship can roll farther and still right itself before the adverse attributes of tumblehome take effect.
This helped, but Northrop Grumman engineers at the model basin are also testing two different bows to see which offers the best mix of stability and stealth. One bow slopes downward somewhat like a submarine’s, while the other flares slightly for greater stability.
The Navy will pick a hull in the next few months, and the choice will not be easy. “We’re running right at” the breakpoint where safety and stealth meet, said Fox, test director for DD(X). The covered test pond — 120 yards long by 80 yards wide — is large enough to accommodate a 13-foot scale model, which routinely sinks in simulated 70-foot seas rolling in at short intervals.
Carderock’s “Hurricane Camille,” however, has become the gold standard for capsize testing, and in this exercise, the model ship performed valiantly. “Of course, we don’t have the wind here,” Reed said. “That would change things.”
Somewhat less complicated is DD(X)’s move to electric power. Many commercial vessels, especially cruise ships, and some Navy noncombat ships are using electric motors for propulsion, but in warships the Navy favors a traditional mechanical approach in which gas or steam turns a turbine connected to a propeller shaft.
DD(X)’s gas turbines, by contrast, drive generators that not only will power the electric motors that turn the propellers, but also supply electricity for everything from weapons systems and computers to the ship’s laundry and stateroom air conditioning.
This “Integrated Power System” has two large 35-megawatt generators and two small 4-megawatt generators, “and all generators have power to supply all systems,” said Michael Collins, the Navy’s program manager for the power systems.
Because it is quieter than a mechanical system, electric drive is good for avoiding detection, Goddard said, but its big advantage is fuel savings. “Gas turbines are more efficient at higher speeds,” Goddard said, “and since we don’t have a dedicated system for main propulsion, we can run the entire ship most times on the two small generators.”
Using electric motors to train the guns and load ammunition and missiles also helps cut crew size, because “without pneumatics or hydraulics,” DD(X) needs fewer specialized personnel, Collins said.
Still, Goddard said the biggest crew reductions will result from an elaborate automation system in which tasks as unrelated as engineering control, weapons and sensors all operate on the same computer network from common consoles at a “ship mission center.” Under such a system, DD(X) expects to have three people standing each engineering watch, for example, compared with “about 13” for current destroyers, Goddard said. The General Accounting Office last year estimated that smaller crew size could save the Navy as much as $18 billion over the life of the DD(X) fleet.
A smaller crew will mean greater creature comforts, especially for enlisted personnel. Instead of gathering in large multi-tiered berthing spaces such as those on most Navy ships, DD(X) crew members will enjoy four-person staterooms.
Above decks, DD(X)’s designers have chosen to build the superstructure out of a composite containing graphite fibers — golf club material — for light weight, strength and rigidity.
Designers will also attempt to reduce DD(X)’s heat signature by cooling the stack exhaust and using materials on the ship’s surface that dissipate the sun’s heat. Such technologies, common on aircraft, make it difficult for an enemy to detect, track and lock infrared sensors on to a target.
Goddard said he is mindful of critics’ misgivings about DD(X)’s crew size, but hopes to use automation to handle damage. “We still have some people who can respond to a casualty,” Goddard said. “But it’s only a third the size of a normal damage-control party.”
© 2004 The Washington Post Company
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