Yes, cavitating torpedoes. The Pentagon has a substantial and active program working on them. But so do a number of other countries, Russia mainly. I remember those articles well . . . But you're right, we don't hear much anymore.
like the supersonic Silkworm missiles - maybe the govt is going by the old saying "if you don't see it or hear it, it can't hurt you?"
with these new weapons, it can almost be true ... you won't feel a thing when you are in a billion particles.