Ill put up some facts. First, depth charges were carried in large numbers and usually dropped as such. Second, launchers for increasing range were also made as early as world war 1.
1 So instead of allowing one depth charge dropped per launcher, allow several dropped at once per short-range launcher.
2 the depth charge fuse idea. Depth charges have timed fuses, so a quicker or slower setting should be there.
3 a RANGED depth charge idea. some depth charges launchers were made to throw a depth charge longer range than dropping them off racks.
4 aircraft depth charges were invented and used during world war 2.
the #1 multiple-drop and #3 ranged depth charge ideas dont really conflict so much as have different kinds. the ranged depth charge would much slower firing for being able to be used outside of point-blank range.