How many depth charges on a destroyer?

Answer 1

Modern Destroyers don't use the type of depth charges used in past wars as the underwater speeds of modern submarines make them obsolete. In WWI and WWII, submarines weren't true submersibles; they were surface ships with limited submergence capability. As such, their submerged speed was much slower than their speed on the surface, and the Destroyer attacking them had the tactical advantage. With the advent of Nuclear Power aboard submarines, Destroyers lost that advantage.

Modern submarines are exactly the opposite; While surfaced speeds are around 17 knots, and official submerged speeds list it as greater than 20 (actual speeds are classified Secret), submerged speeds would shock most people not privy to the information. For that reason, and the fact that modern boats have a much deeper submergence capability, traditional depth charges are useless; by the time a charge sank to a target depth, the speed of the boat could have it a long way from the charge when it exploded.

Modern Destroyers rely on several key weapons systems for ASW;

Helo's - Helicopters with sonobuoys and dipping sonar, and armed with Mk 48 ADCAP torpedoes, are one of a Destroyer's most potent weapons (at least they think so).

Torpedoes - So far no submarine can outrun an active homing torpedo that has a lock on its target.

ASROC - Nuclear depth charge, launched as a standoff missile, deploys warhead and explodes at predetermined depth.

While Destroyer crews like to think they have the advantage (good morale booster), in reality the best weapon against a submarine is another submarine. Modern boats are so quiet and fast that a Destroyer would be running from a torpedo, Tomahawk Anti-Ship, or Harpoon missile before it even knew a submarine was tracking it, and modern systems allow for multiple target tracking and targeting of weapons.