Blert;

Nope. Kilotons.
The key to the effectiveness of the submarine launched Polaris A-2 and A-3 was miniaturization of the warheads, something the Soviets never got right.

As for accuracy, the A-2 could spot a baseball diamond at max ramge,
The A-3 could spot the pitcher’s mound. The A-3 also incorporated a MIRV array that triangulated the target; big boom outside the array, but huge compression on the interior of the pattern, which dramatically increased the effective power of the weapon. Most importantly, these birds worked. Failure rates were very low, and there were shots made thoughout the 3 decades thaqt these ships served.

The FBM end of the triad was the survivable part. After ’61, penetration of Soviet airspace by fixed wing bombers was not possible because of Soviet missile air defences (remember Gary Powers?), unless the AIr Force deployed standoff weapons. Land based ICBMs were vulnerable because their launch facilities were fixed and were subject to location via on-ground intel gathering by the Soviets and their embedded agents in the US. The boomers were basically undectectable, except by sonar, until the end of the cold war, when satellite technology advanced sufficiently to make thermal detection from orbit likely. The standard FBM (598 through the 640 classes) had 16 missile tubes, and the follow-on Ohio class had 24. In 1973, all 41 boats of the original force were in service (656 possible SLBMs). (in October 73, two were not avaialble) The boomers would have been vulnerable after the first launch. Depending on the amount of traffic inbound into the USSR from the boomer fleet, the computed ballistic of the missile could conceivably be computed to point of origen and a return shot made; in the water, close is good enough with nuclear weapons. A small nuclear weapon cooked off under the surface would only have to be within a few kilometers to disable the boomer’s ability to launch additional missiles (and probable breach of the pressure hull by the pressure pulse emanating from the detonation site), because of the relative fragility of the missile guidance packages.

We never pulled the trigger. Had we ever done so, the immediate loss of life would have made the predations of the 20th century dictators seem as child’s play. And the survivors would probably have had no reason to be thankful.