The Navy’s New Mach 7 Cannon Could Be a Game Changer

By Rich Smith | More Articles | The Motley Fool

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Ready to aim and fire — behind the scenes at the Navy’s new electromagnetic railgun. Source: U.S. Navy.

The U.S. Navy has a Mach 7 cannon, and it could start shooting as early as 2018.

That’s the upshot of a new report from the U.S. Naval Institute, which says the third Zumwalt-class Navy destroyer could have one of its two 155 mm Advanced Gun Systems switched out and replaced with an experimental electromagnetic railgun. Quoting Naval Sea Systems Commander Vice Adm. William Hilarides, referring to real-world tests of the prototype announced last summer, USNI noted that “real engineering studies are being done to make sure it’s possible.”

Hilarides further confirmed that he will “certainly” recommend installing one of the new weapons on a Zumwalt. “Probably the third ship is where we’d have it,” said the Admiral.


One of two railgun prototypes (this one by General Atomics) undergoing testing aboard the joint high-speed vessel USS Millinocket (JHSV-3). Photo: U.S. Navy.

What’s a railgun — and why a railgun?
But let’s take this from the beginning. The U.S. Navy has a problem: The sequester is cutting its budget, limiting its ability to buy ships, to build big ships, and to stash expensive weapons systems upon them. The Navy’s new electromagnetic railgun, though, has the potential to solve all three of these problems.

In essence, a railgun is a high-tech cannon, but powered by electricity rather than gunpowder. Using an electromagnetic energy known as the “Lorentz force,” it fires projectiles at speeds upward of Mach 7 — 5,000 mph — and can hit targets as far away as 100 miles. The projectiles are nonexplosive (they derive their destructive power from the kinetic energy of their speed). As such, they can’t be “blown up” by hostile fire striking a warship’s ammunition magazine. Each projectile is only 18 inches long — so they take up less space than, say, a cruise missile with similar destructive potential.

And each projectile costs only $25,000. That is significantly less than the cost of a Tomahawk cruise missile.


An electromagnetic railgun projectile. Small as a breadbox, and nearly as cheap. Photo source: U.S. Navy.

Thus, in arming a Zumwalt-class destroyer with a railgun, the Navy can simultaneously:

  • Enhance the warship’s effectiveness: The Advanced Gun System the railgun replaces has an effective range of only 75 miles.
  • Save money: A railgun projectile can do the same work as a Tomahawk missile, but costs 1/60th as much.
  • Save space: Because they are so small, you can fit more railgun projectiles aboard a boat.
  • And thus save more money: Smaller munitions mean you can build smaller warships, and build fewer ammunition ships to keep them supplied.

This, in a nutshell, is why the Navy is so excited about railguns — and why it’s rushing to get one aboard the Zumwalt-class destroyer USS Lyndon B. Johnson (DDG-1002) by 2018.


Photo source: U.S. Navy.