Saturday, August 02, 2008
New DDG-51s Could Get Tweaks, Upgrades
New DDG-51s Could Get Tweaks, Upgrades
2 August, 2008: Even though the U.S. Navy will resume building Arleigh Burke-class destroyers because the ships are cheaper and the costs are predictable, the eight new Burkes could get new refinements that set them apart from earlier siblings, according to a congressional report.
According to written testimony submitted July 31 to the House Seapower Subcommittee by Navy shipbuilding expert Ron O'Rourke, the Navy has several options to improve and accessorize the new series of destroyers that will resume with the ship carrying hull number DDG 113.
The Navy acquisitions officials who appeared before the subcommittee July 31 said there isn't yet a plan for how and when to begin the paperwork for buying the new ships, which take the place of five bigger, more advanced Zumwalt-class destroyers. The general sense was that the new Burkes would correspond to the Flight IIA standard - including the latest SPY-1 radar- and be equivalent to ships that had been upgraded with the Navy's DDG Modernization, which includes open architecture, consumer off-the-shelf systems.
Testifying for the Navy were Vice Adm. Barry McCullough, deputy chief of naval operations for integration of resources and capabilities; and Allison Stiller, deputy assistant secretary of the Navy for ship programs.
According to statistics provided by the Navy, the estimated cost for two new DDG 51s is about $3.5 billion, as compared to an estimated $3.2 billion per ship for DDG 1000. But lawmakers, including the Seapower Subcommittee's chairman, Rep. Gene Taylor, D-Miss., hope that serialized production for new DDG 51s would bring down the per-ship costs by the time the next copies are being built. Stiller said it would take extra money and about 50 additional weeks to re-start production on the destroyers' main reduction gear, which ended when the Navy ordered what it thought would be the final ships in the class.
Shipbuilders at Bath Iron Works in Bath, Maine, are already at work on what was formerly the last destroyer, the Michael Murphy, the 62nd ship in the class. The cost for each ship of that vintage is about $1.3 billion.
O'Rourke's report spelled out a number of options that the Navy could request for its new ships, from money-saving possibilities to new propulsion systems to new weapons.
Apart from adding technology, the report's first money-saving option is to reduce crew sizes as much as possible. The House Armed Services Committee in 2005 gave the Navy a goal to reduce destroyer crew sizes from around 300 people to 200. That same year, the Navy reported to Congress that a Burke cost $25 million per year to operate, of which its crew cost $13 million. The more people the Navy can take off its warships, the more money it saves, O'Rourke wrote.
As for upgrades to the ships themselves, the report mentions that if the new generation of DDG 51s included some of the technology from the DDG 1000s' all-electric drive system in a "hybrid plant," the new destroyers could use at least 16 percent less fuel. In the near-term, though, the novel gas-turbine and electric power plant would cost about $17 million to develop and add just under $9 million to the cost of each ship.
Another potential fuel-saving upgrade would be a second bow bulb, located just above the sonar dome protrusion on the existing generation of destroyers. According to internal Navy studies, O'Rourke wrote, the second bow bulb would improve the ships' fuel efficiency by about 4 percent and lead to slightly better speed and range.
The report also posits that a new DDG 51 could be outfitted with the 155mm Advanced Gun System that the DDG 1000 was intended to carry. With a range of 63 nautical miles and highly precise guided ammunition, the AGS is a much deadlier and longer-range gun than the 5-inch gun carried aboard today's Burke-class destroyers.
O'Rourke's report quotes Navy studies that found a DDG 51 could carry an AGS forward of its superstructure, but only if its existing gun and missile tubes were removed. Even then, the ship could only carry 120 rounds for the larger gun, as opposed to the 600 rounds a DDG 1000 would carry for its two AGS guns.
But there may be no need for an AGS after all, according to testimony July 31. The gun was designed to provide long-range fire support to Marine Corps forces ashore, in the tradition of the 16-inch guns carried aboard Navy battleships of yesteryear. That fire-support mission can now be handled by Tactical Tomahawk cruise missiles and precision air strikes, McCullough told the seapower subcommittee, and the Navy was studying ways to provide more long-range fire support from the new littoral combat ships, which carry a 57mm gun.
There is a limit to how many upgrades engineers could shoehorn into a DDG 51 hull, which is about 100 feet shorter and 6,000 tons lighter than a DDG 1000. O'Rourke wrote that if the Navy wanted its new Burkes to have a radar system comparable to the one meant for the DDG 1000, there's a good chance the new destroyers would need to be longer and heavier, or lose some of their existing weapons.
One alternative, he wrote, was to mount an advanced new radar on what he called a "non-combat adjunct ship," a vessel built around the powerful dual-band radar that was to have been fitted in the DDG 1000's composite deckhouse. The radar ship wouldn't be armed, but would travel with surface task groups and feed the other ships data from its sensors. If there were an attack, the warship escorts in formation with the radar ship would need to defend it.
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