Abstract: Shells fired from the gun of a ship create an underwater explosion that is used to drive a sonar system. Sonobuoys [201] and/or a ship-towed array measure acoustic signals caused by the underwater explosion. A ship processing component [306] analyzes the signals and locates reflections of objects [102] in the signals. In addition to controlling the location at which to fire a shell, an adjustable fuze on the shell may be set to thereby control the depth at which the shell explodes. The low-frequency impulsive nature of the explosion makes it particularly suited for detecting objects in a littoral environment.