Naval Guns: Can They Deliver 'Affordable' Precision Strike?

• Author: Erwin, Sandra I.

In the U.S. Navy's plan for fighting wars in the future, combat ships will serve as mobile sea-based artillery, providing fire support from as far away as 100 miles. Advanced naval guns shooting satellite-guided munitions, officials said, will provide the same land-combat firepower that today would require several batteries of howitzers. Further, if the new gun systems work as advertised, they would allow the Navy to hit targets ashore for much less than what it costs to strike with Tomahawk cruise missiles.

"We want an affordable round to do a small hole in a building, right where you want it. [But] we don't want to spend a million dollars a pop," said Capt. Tom Bush, program manager for the Navy's futuristic destroyer, called the DD-21.

But Bush cautioned that long-range naval guns will not replace tactical missiles and are not here to rake away land-strike naval aviation. ... [They are] just a small part, an affordable small part."

The so-called land-attack mission by the U.S. Navy has become a linchpin of the service's plan for fighting future wars, and is driving a $25 billion investment in DD-21.

Several more billions, additionally, will be spent on new 5-inch guns and smart munitions for the current Arleigh Burke guided-missile destroyers, the DDGs. The upgraded 5-inch 62-caliber guns--designed for a land-attack role--are expected to launch guided projectiles out to at least 41 nautical miles (nm).

By comparison, the current 5-inch, 54-caliber gun fires out to 13 nm.

Since the Navy did away with the 16-inch gun-equipped battleships, it only has used 5-inch versions. But after conducting several studies, the service decided that the 5-inch size offered limited capability for long-range strikes with smart munitions, so it decided that its new land-attack ships, the DD-21s, would have bigger guns.

The DD-21 Zumwalt-class destroyers will have, unlike any other ship, 155mm guns, two per ship. The Navy decided to go to a 155mm caliber, equivalent to 6 inches, because it wanted both a larger projectile and one that would have some commonality with heavy land-combat ammunition, which also is 155mm.

Going from a 5-inch to a 6-inch gun drastically changes the rules of the game, said naval experts. With a larger gun, more lethality comes not just from bigger projectiles but also from the ability to increase the length of the rocket motor in guided rounds, so they can travel farther.

The 62-caliber gun for DD-21, called the advanced gun system (AGS), will fire 12 rounds a minute and largely will automate the ammo-loading process. This is an important consideration, because DD-21 will sail with two-thirds fewer crew members than the DDGs.

The AGS primarily will be a land-attack weapon, but also could serve in anti-surface warfare missions. It will be able to fire both long-range guided munitions and traditional ballistic ammunition.

"This is the first modern naval gun where the ammunition is part of the naval gun-system development," said John M. Paul, AGS deputy program manager at United Defense LP, in Minneapolis. The company is designing the gun and also is responsible for the initial development of the long-range guided projectile.

Last August, UDLP awarded two contracts for the guided projectile design: one to Science Applications International Co. (SAIC) and one to the Raytheon Co. The two...