Defense Technology International - September 2007 - (Page 48) ORDNANCE NAVAL LONG SHOTS Naval gunnery is back in fashion as surface ships go for greater impact BILL SWEETMAN • MINNEAPOLIS BAE SYSTEMS uns on warships are like the guns on fighter aircraft, in that they have often been considered on the road to extinction. When the U.S. Navy’s gigantic Iowa-class battleships were decommissioned in 1992, the era of 16-in. guns firing 2,700-lb. shells ended forever. Arguably, advances in ship gunnery had stopped long before, with the automatic high-rate-of-fire 8-in. (203-mm.) weapons on the Des Moines cruisers. The 4.5-in., 5-in. and 130-mm. guns on more modern warships—all in the same overall class—were secondary armament, the main offensive and defensive weaponry comprising missiles. But gunnery is making a comeback because the role of the warship is changing once again. One of the main functions left for a non-aviation surface combatant is to support land combat in littoral regions, particularly in the opening stages of a conflict before airports and seaports are secure. Amphibious and airborne forces flow into a combat zone along slender pipes, and the presence of a warship can let them leave heavy artillery behind the first waves. However, contemporary naval guns don’t 48 G The rocket-boosted Long Range Land Attack Projectile, being designed by Lockheed Martin for AGS, breaks range records for gun-launched systems. shoot far enough to provide much help to land forces. A recent example of a naval gunfire operation that made the headlines was the firing by the Aegis destroyer USS Chafee (DDG-90) of “more than a dozen” unguided shells from its 5-in./54-cal. BAE Systems Mk 45 Mod 2 main gun on the position of a suspected Al Qaeda operative in northern Somalia on June 1. But this was unusual: with a range of 13 naut. mi. (24 km.), the Mk 45 is normally useless for fire support. Now, the U.S. Navy has two major gun programs in the works. Underway for many years, and not without its challenges, is the Raytheon-developed EX171 extendedrange guided munition (ERGM), which is intended to dramatically increase the range of the Mk 45s fitted to Arleigh Burke-class destroyers: the modified gun and rocketboosted, guided shell are intended for a range as high as 63 naut. mi. (117 km.), al- lowing them to shoot 38 naut. mi. (70 km.) inshore from a 25-naut.-mi. standoff range. For example, a ship sailing off Dover could hit the Defense Systems & Equipment International site in London’s Docklands. The 155-mm. Advanced Gun System (AGS), under development for the DDG1000 Zumwalt-class destroyer, is even more ambitious: the biggest new naval gun designed since World War II, it is intended to lob its Long Range Land Attack Projectile (LRLAP) to ranges of at least 83 naut. mi. (150 km.). This is almost four times the range of the guns on the Iowa-class battleships, and exceeds the range of the ultralong-range “Paris gun” fired by Germany in World War I. ERGM started as a Texas Instruments program in 1996, with the goal of initial operational capability (IOC) in 2001. The program is now under contract with Raytheon, which acquired TI in 1997, and is not expected to achieve IOC until 2011. “If it was easy, it would have been done a long time ago,” comments Navy program manager Capt. Lee Bond. ERGM is a GPS-inertial guided, rocketboosted munition with fold-out tails and movable canard steering fins. Initially designed to carry a payload of submunitions, it was redesigned with a unitary payload in 2002. Only two of seven test flights in 2005 were regarded as anything except failures. “The shock of accelerating from zero to hypersonic speed is kind of hard on the electronics,” says Bond with some understatement. In 2004-06, the Navy explored an alternate round, the Ballistic Trajectory Extended Range Munition (BTERM) from ATK, but this too experienced test failures and the Navy canceled it, although development continued through Fiscal Year 2006 under congressional funding. Meanwhile, Raytheon has produced a redesigned ERGM system—that addresses both technical and obsolescence issues—while BAE Systems and the Navy have worked on making acceleration within the gun more stable. The Navy has also reduced the number of ERGM-capable ships, abandoning plans to equip 22 Ticonderoga-class cruisers with the weapon. It will now be fitted to the last 32 Burke-class ships, starting with DDG-81 Winston S. Churchill, which carry the improved 62-caliber Mk 45 Mod 4 gun. The redesigned—and, it is hoped, definiwww.aviationweek.com/dti DEFENSE TECHNOLOGY INTERNATIONAL SEPTEMBER 2007 http://www.aviationweek.com/dti
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