Underwater drones, torpedoes, and cheap mass

Are modern underwater drones more dangerous than torpedoes or airborne drones, and how can they be intercepted?

Large underwater drones can approach torpedo-like danger, while smaller littoral craft are harder to find; the wider challenge is restoring affordable defences against mass attacks.

Large underwater drones can resemble torpedoes in the danger they present, while smaller craft trade explosive power for concealment and manoeuvre in the littorals. The smaller systems create a different detection and interception problem. Western procurement concentrated on hypersonic missiles, lasers, and other high-end threats while allowing affordable defences against cheap mass to weaken. The Italian Navy's use of 76 mm guns shows that established naval weapons can still answer part of that problem.