The "Tauchpanzer" or deep-wading tank (also referred to as the "U-Panzer" or "Unterwasser Panzer") was a standard Panzer III or Panzer IV medium tank with its hull made completely waterproof by sealing all sighting ports, hatches and air intakes with tape or caulk. The gap between the turret and hull was sealed with an inflatable hose while the main gun mantlet, commander's cupola and radio operator's machine gun were given special rubber coverings. Once the tank reached the shore, all covers and seals could be blown off via explosive cables, enabling normal combat operation.