New partly armoured German submarine type built according to the Dutch magazine Marineblad dated 1915-1916 no. 6

An item referred to the magazine Naval and Military Record reporting that in Germany a submarine of a new design was built. Above the circular shaped hull was an armoured superstructure (called a battery) placed which could be watertight closed. Within the battery was the conning tower situated. The calibre of her guns was unknown. Her main task was chasing merchant ships and to be ballasted in such manner that just the superstructure pointed out of the water making the light guns of the merchant ships useless. If an warship approached her was the superstructure to be closed and dived the submarine.