The "U-5"-class boats had a single-hulled design with a teardrop shape that bore a strong resemblance to modern nuclear submarines. The boats were just over long and displaced surfaced, and submerged. The torpedo tubes featured unique, cloverleaf-shaped design hatches that rotated on a central axis. The ships were powered by twin 6-cylinder gasoline engines while surfaced, but suffered from inadequate ventilation which resulted in frequent intoxication of the crew. While submerged, they were propelled by twin electric motors. Three boats were built in the class: U-5, U-6, and .