The naval vessels aren't as much of a concern as seemingly safe Iranian freighters.
Because Iran test fired some of their Shahab-3 missiles from freighters. The missiles were detonated at a high altitude - just like what would be done to generate an EMP attack.
More than likely Iran is doing the military move in an attempt to lull the US to sleep. Down the road, they will start sending out the freighters. When they observe that the US is no longer tailing them, the next set of freighters will be armed with the missiles.
All internet will be taken down as well as electricity for refrigerators and everything else including gas pumps and ATM machines. Cars and trucks that are on the road will have their electronics fried, creating accidents and traffic jams all over the country.
Jet planes will fall from the sky starting thousands of fires. Trucks won't be able to reach them due to the traffic jams.
If you're on an elevator when it happens, that's where you'll spend your final days urinating, etc.
Doom? What doom?