The risk of an accident or otherwise unintentional initiation goes up with the number of warheads deployed. https://en.wikipedia.org/wiki/Soviet_submarine_B-59

The risk of an accident or otherwise unintentional initiation goes up with the number of warheads deployed. https://en.wikipedia.org/wiki/Soviet_submarine_B-59#Nuclear_close_call https://en.wikipedia.org/wiki/Soviet_submarine_B-59#Nuclear_... (or of course Dr Strangelove)