All Naval Ordnance

Naval Ordnance groups the self-propelled and deployed underwater weapons carried by warships, distinct from gun-fired naval artillery. The class covers the torpedo, a self-propelled explosive weapon that runs to its target underwater; the depth charge, a weapon simply dropped or thrown overboard to explode near a submerged target; and the naval mine, a stationary explosive device laid in the water to damage or destroy a ship that strikes or approaches it. Wikipedia's Naval artillery article draws this exact boundary, stating that the term naval artillery excludes self-propelled projectiles such as torpedoes and weapons simply dropped overboard such as depth charges and naval mines; this invention class gathers those three excluded, non-gun naval weapons as their own coherent technology family.