Japan Becomes 1st Country Ever To Fire Electromagnetic Railgun From An Offshore Vessel::Japan has successfully test-fired a medium-caliber maritime electromagnetic railgun from an offshore platform, as it continues to advance its defenses in the face of burgeoning regional security threats.
You’re thinking of EMALS. It’s a catapult for aircraft, not a gun. Pretty close in concept though. Had some teething issues, turned out larger than expected, but works just fine now.
The GAO says it still has reliability issues that won’t likely be ironed out for about a decade.