ASW mortars for littoral underwater threats

What naval technology from history would be worth redeveloping?

Anti-submarine mortars deserve another look for littoral threats, though the proposal remains open to disagreement.

Anti-submarine mortars offer an area-effect response to shallow-water submarines and uncrewed underwater vehicles in the littorals. Their spread could cover a patch of water where a precise attack is difficult, making the old weapon type worth renewed study. The proposal remains tentative because most people consulted about it have argued against the idea.