T2K Naval War in the Pacific

[Matt Wiser]

I believe that was one of the original strategic missions for Soviet subs: firing nuclear torpedoes into NATO ports. The Type 53-68 nuclear torpedo is a straight-runner, with a 10-20 KT yield. It's getting into range of a port, with the ASW defenses usually present, that would be the problem.

The Mark 45 ASTOR nuclear torpedo for the USN was retired in 1977.

An alternative weapon would be standoff ASW rockets like the SS-N-15/16 or SUBROC/Sea Lance. They're meant to kill ballistic-missile subs at standoff range, especially if they're getting ready to fire. They don't move-and neither do ports. Simply fuze the nuclear depth charge to detonate shallow, and you do wreck the port and the ships in it.