The JHSV has 600 tons of excess payload capacity, but Zumwalt Navy destroyers have 20 tons of excess payload capacity. The railgun will need to be made more compact to be installed on the destroyers. The Destroyers at 14500 tons are bigger than the JHSV. The Destroyers are already filled with other systems.
The railgun also uses 34 mega joules of power to launch a 23-pound projectile to distances greater than 100 miles at speeds topping Mach 7 (better than 5,300 mph). While Zumwalt-class destroyers will generate roughly 78 mega joules (twice the power the railgun needs), most destroyers have in reserve less than one-third of the power the railgun needs. And there are a whole bunch of limitations on what can be done inside the ship to add power generators. Developers will house power generators in con-ex boxes during the JHSV demonstration, but a permanent power solution will be needed before the railgun lands in the fleet.
UPDATE - The US Navy has a thirty year roadmap for new ships and for improvements to power systems to power railguns and lasers.
Aegis is a fully integrated combat system on cruisers and destroyers, and the railgun's fire control loop doesn't yet know how to talk to that system. Railgun fire control will need Aegis integration.
The target is 2018 for installation of a combat railgun on a US Navy destroyer.
Engineering studies to include an electromagnetic railgun on a Zumwalt-class destroyer (DDG-1000) have started at Naval Sea Systems Command, NAVSEA’s head said Thursday.
The work will do the math to determine if the Zumwalt-class will have the space, power and cooling to field a railgun – likely replacing one of the two 155mm BAE Advanced Gun Systems (AGS) ahead of the ship’s deck house.
The likely candidate for the weapon would be the third planned Zumwalt, Lyndon B. Johnson (DDG-1002) currently under construction at General Dynamics Bath Iron Works (BIW) with an expected delivery date of 2018.
An electromagnetic railgun prototypes on display aboard the joint high speed vessel USS Millinocket (JHSV 3) in port at Naval Station San Diego, Calif. US Navy Photo
The integrated power system (IPS) on the 16,000-ton ships– powered by two massive Rolls Royce MT-30 gas turbines and two smaller Rolls-Royce RR450– allow the ships to route and generate 80 mega-watt power – much more electrical power than the current crop of U.S. destroyers and cruisers.
Zumwalt-class guided-missile destroyer DDG 1000 is floated out of dry dock at the General Dynamics Bath Iron Works shipyard on Oct. 28, 2013. US Navy Photo
The Office of Naval Research (ONR) and BAE Systems are developing the next-generation HVP, Hyper Velocity Projectile, that can be fired by the EM Railgun and future models of railguns.
The HVP will also be compatible with current weapons systems like the Navy 5-Inch Mk 45, and Navy, Marine Corps, and Army 155-mm Tube Artillery systems.
The Navy’s EM Railgun will fire 10 of these rounds per minute. When fired with an Mk 45 the HVP will be 20 rounds per minute and extend range to 50 nautical miles.
Railguns do not use gunpowder or propellant to fire the projectile. It reduces the need for high explosives to be carried on ships and the related hazards in doing so.
Railgun projectiles are a mere fraction of the cost of those currently used in missile engagements – possibly even one percent of the cost of today’s missile systems.
Speed and Range
The shots can reach seven times the speed of sound. The shots can reach a range of over 100 miles.
SOURCES - Navy Times, Wikipedia, USNI, Fox News, Youtube