OVERVIEW: Depth charge mortars are anti-submarine weapons that launch explosive charges into the water using a mortar-style mechanism. Unlike traditional depth charges released directly overboard, these systems extend the engagement range, allowing ships to project charges ahead or to the sides while maintaining distance from the target area.

DETAILS: These systems fire small to medium-sized depth charges using compressed gas or explosive propellants. Upon water entry, the charges sink to a preset depth and detonate using hydrostatic or time-delay fuzes. The blast creates intense pressure waves designed to compromise submarine hulls or systems. Depth charge mortars are typically arranged in trainable or fixed launchers and can deploy single charges or salvos for pattern saturation. They are particularly useful for engaging close-range submerged threats while maneuvering or during escort operations.

ROLE SUMMARY:
Category: Anti-Submarine Warfare Munition
Primary Use: Anti-submarine (close to mid-range)
Function: Indirect underwater detonation via projected charge
Strong Against: Shallow and medium-depth submarines, submerged threats near escorts
Weak Against: Deep-diving submarines, high-speed submarines, surface vessels
Platform: Surface warships with ASW roles
Integration: Compatible with depth charge mortar systems such as Hedgehog, Bofors, or RBU-series launchers

SOURCE:
Janes Naval Weapon Systems
https://en.wikipedia.org/wiki/Anti-submarine_mortar