“unless of course the DDG was dead in the water and blind from an EMP”
Any EMP capable of both disabling and blinding a USN DDG would have done the same to all ships in the vicinity.
The DDG is hardened against EMP by design. They are designed to fight in a nuclear environment.
And the power plant is BELOW THE WATERLINE.
Not plausible.
Tell that to the crew of the USS Donald Cook in the black sea where the russians hit them with the Khibiny device.
It is plausible. There are weapons that can be effective against hardened emp systems.