Right there in the article:
"The idea is, if you build a big enough bomb and blow it off in coastal waters, it will create a 1000 foot high nuclear tidal wave that will physically wipe out coastal cities and Naval installations, as well as pollute them with radioactive fallout."
"Worse still: blowing up a 1-100 megaton device in coastal mud will make lots of nasty fallout. Sodium-24 (from the salt in the water) is deadly."
That sounds unrealistic especially if it insunuates a device will wipe all all the East coast cities.
It seems anything they have will be able to wipe out all the stuff they want to wipe out just with ICBMs.
If this ever comes into play it is all over anyway.
Well, they'd have to use more than one.
> It seems anything they have will be able to wipe out all the stuff they want to wipe out just with ICBMs.
The idea is that this sort of weapon is a response to US anti-ICBM systems, so Russia can maintain their MAD.
For that matter, why even be tactical about it? Just drop it off a cargo ship into the bay and let it sink under 20 feet of mud, then if war ever comes, detonate it remotely. (How you say? Obviously, signal it seismically from the other side of the planet...)
If it was for coastal destruction why not drop it to the bottom and then swim away and let it denotate in safety.
But in general why even bother, why not launch the 20M warhead as an ICBM and detonate above the target zone. Wouldn't water just dissipate the energy and waste it? This sounds like science fiction more than anything. Kind of like how we trolled Soviet Union with Star Wars.
BTW: Nuclear torpedos existed since at least late 50s and almost started WWIII around the Cuban Missile Crisis times. There was even a hero who saved the world related to it: https://en.wikipedia.org/wiki/Vasili_Arkhipov.