I don't know if this is the same mod, but it is a somewhat nuclear torpedo:
https://www.subsim.com/radioroom/dow...o=file&id=1210
(was just a mater of searching the download section for "nuclear"
Probably because it is so OP it didn't appeal to the masses and got lost in history.
(the link in the video description doesn't seem to work that well. And when it did, my virusscanner frowned upon it.