A German World War II close defense weapon system for tanks. As you may know, tanks, being heavily armored, have very limited vision outside and, as such, are very vulnerable to infantry close range assaults. A common solution to this during WW2 was to make pistol slits to the sides of the vehicle, enabling the crew to fire at assaulting infantry. Of course, these slits made the crew more vulnerable to enemy fire, so this was not the optimal solution. Also, the slits didn't entirely solve the problem of dead zones, which are areas around the tank to which the crew cannot see or fire at.
Another problem with tanks and close combat with infantry was that the external smoke dischargers (Wurfbecher) mounted on the sides of turrets were very vulnerable to small arms fire. The smoke charges in them would often ignite in a firefight, incapacitating the tank crew with their smoke.
The Nahverteidigungswaffe (NahVW) killed two birds with one stone by solving both of these problems. It was a 92mm breechloader smoke discharger mounted inside the turret with no barrel visible, so it could be reloaded from inside the vehicle during combat and was protected by the turret armor. The launcher itself only fired smoke rounds, but if the breech was opened, high explosive grenades and other munitions could be fired through it using a normal flare gun (Leuchtpistole, or Kampfpistole, a rifled flare gun). The grenades had a timed fuse that exploded them slightly over ground, making them lethal to infantry even in dead zones of the tank.
The NahVW was first introduced in March 1944, mounted on Tigers. It was later mounted on at least the following vehicles and probably other late war tanks as well: Königstiger, Panther, Jagdpanther, Jagdtiger, Sturmtiger, StuG III and Pzkpfw IV.
Ammunition
- Smoke round (Schnellnebelkerze 39)
- High explosive grenade (Sprenggranatpatrone)
- Colored smoke cartridge (Rauchsichtzeichen 160)
- Signalling and illumination rounds (Leuchtpatronen)
Sources:
http://www.custermen.net/nahvert/nah.htm