WASHINGTON — One of the prime attributes of the DDG 1000 Zumwalt-class destroyers is the design's 78-megawatt integrated power system, able to switch electrical power between propulsion, sensor and weapon systems. It's long been touted as the best platform to field new energy-gobbling weapons like rail guns and lasers.
A year ago, however, it appeared the first ship that might carry a rail gun to sea might be a joint high speed vessel (JHSV) fitted with a temporary installation. Briefers at naval exhibitions spoke publicly of the plans, and at least one model of the proposed demonstration was on display.
Plans for the at-sea demonstration remain in place, officials said, but it's looking more likely that a test using an expeditionary fast transport (EPF) — the new designation for JHSVs — won't take place at least until 2017, if at all.
"What I'm finding is if I go ahead with the demo it will slow my development," Rear Adm. Pete Fanta, director of surface warfare, said during a Dec. 30 interview at the Pentagon. "I would rather get an operational unit out there faster than do a demonstration that just does a demonstration.
"It's not definitely off but it's not definitely going ahead," Fanta said, "primarily because it will slow the engineering work that I have to do to get that power transference that I need to get multiple repeatable shots that I can now install in a ship. And I would frankly rather have an operational unit faster than have to take the nine months to a year it will take to set up the demo and install the systems, take the one operational [rail gun] unit I have, put it on a ship, take it to sea, do a dozen shots, turn around, take it off, reinstall it into a test bed."
Officially, the JHSV/EPF demonstration is still on the books.
"The plan to perform the at-sea demo in 2016 is still on," said Matt Leonard, a spokesman at the Naval Sea Systems Command (NAVSEA). "Basically there's been no change to the plan, but discussions are ongoing."
The Zumwalt at sea in December. Her two 155mm Advanced Gun Systems are enclosed on the foredeck. The Navy is considering installing a rail gun in the second position.
Photo Credit: US Navy/General Dynamics Bath Iron Works
NAVSEA is acting as the system engineering lead for the JHSV/EPF demo, coordinating with the Office of Naval Research and the Military Sealift Command.
Other sources said they were unaware of much planning about the demo. "It's not been a topic of discussion," one source said, "but I've not heard anything to say the testing on an EPF is not going ahead." Even if it were to proceed, another source added, "at this point we think the most likely time will be in mid-2017."
But Fanta is focused not on the demonstration, but on driving to an operational system.
"There are two technologies coming out of the rail gun program that both show very high promise," he said. "One is the rail gun itself, and two is the projectile we need to shoot out of that rail gun, a hypervelocity projectile. Something that goes at high speeds that comes out of that barrel and is able to hit a spot multiple dozens of miles away."
The goal, he said, is to make the projectile "usable for more than just rail gun. Can I take my powder guns and use that same sort of projectile?" The technology in the projectile, he added, "actually is what enables it to fly that distance with that accuracy."
Both the rail gun and laser weapons have moved from theoretical concepts and are approaching the developmental stage.
"It's engineering at this point, it's no longer science," Fanta said. "It's no longer the deep dark secrets of what can I do with this sort of energy. It's engineering and how much power density can I get, how much beam quality can I get, what sort of metallurgy do I need to sustain multiple shots over multiple periods of time. The rail gun as well as the laser."
His office is also rethinking the way the gun system is conceived.
"My old gun barrels used to last me a few thousand rounds. Is that still the way we want to go? Other countries are solving it the other way. Maybe if I carry four barrels and have them easily swapped out with a bunch of bosun's mates on the foc'sle and stick 'em in and a half-turn and you go. It's kind of the way we do it when we overheat machine guns. The new machine guns, you got the old barrel, you stick in a new one and you keep shooting. Maybe that's the way to go if we can't solve the metallurgy issues that allow me to do 1,000 rounds out of a barrel."
Fanta is eying the number two main battery position on the destroyer Lyndon B. Johnson (DDG 1002), third and last of the Zumwalt class, as a prime candidate to take the first at-sea rail gun. The ship, under construction at Bath Iron Works, carries two 155mm Advanced Gun Systems (AGS) in those positions.
"Would I like it on DDG 1002? Yes. That would be my goal," Fanta said, noting he has looked at installing an operational rail gun just before the ship "gets ready to go to its first deployment. I need to be able to have a power generation, a power transference and the barrel round integration to work for that level of integration to get out there."
But, he cautioned, "I don't know if I can get there from the engineering status yet. But that's what we continue to look at."
Fanta was adamant that an operational rail gun is fast approaching. When asked if he could field an operational unit in five years, he was adamant.
"Yes," he said, then repeated it.
There has been no decision to switch out the AGS, he said, and both guns and their large automated magazines are still scheduled to be installed on the ship at Bath.
And while NAVSEA is working on how a rail gun system would be installed on the Johnson, Fanta is also looking for a bigger test range to shoot the rail gun, now at the Naval Surface Warfare Center in Dahlgren, Virginia. One possibility, he acknowledged is the huge White Sands Missile Range in New Mexico.
"I need to be able to see how this thing — for both the projectile and the gun — how it shoots at full range, which means I need both elevation and altitude and long range where I can go blow the top off a mountain someplace and not worry about someone fishing around somewhere.
"The discussion now," he added, is whether to "move it to a better site that allows me to do full range testing, or do I go do the demo? Because it's an either/or, it's not both at this point."
Christopher P. Cavas was the naval warfare reporter for Defense News.