First off, most Navy ships should have a backup to the backup steering system, which is manual and doesn’t need power. And an EMP burst will likely damage enough stuff / your engine to where it doesn’t work, and you’ll slow then drift, not just keep going.
But your article is ridiculous, the dude is going on about a conspiracy within a conspiracy (his words, not mine). I’d take that whore article with a pretty big grain of salt.
And what does an EMP have to do with GPS spoofing?