As with the other reinforcement of the sea fortress, in connection with the defense system in 1867, there had been talk of building a fort on the Middelgrunden, which was abandoned at this time.
Instead, it was built in the years 1890 – 1894 on the northern part of the Mediterranean.
The task was to prevent the bombing of Copenhagen, to protect Copenhagen’s northern mine block and to prevent enemy units from entering the straits.
The foundation is built of timber counters and concrete counters secured by a boulder glaze. A cover mill surrounds the island itself with the wet tomb and the outside harbor. Facing the outside port is the Peace Barracks, which on two floors contain occupancy rooms, galley, officer’s homes and trade fairs. At the lower floor is the fort’s casemates, which include ammunition magazines, war barracks, hospital, power plant, naval station and offices. The war barracks, located in the center of the casemates, are protected in the horizontal direction of 30 meters of ground and in the vertical direction of 13 meters of ground.
The shot was set up in batteries on open concrete foundations, circularly arranged around a center traverser. All of the batteries were connected to a partially covered ammunition corridor that was connected to the underlying ammunition magazines by ammunition elevators. The fort’s fire control center was set up around the center traverse, whereupon a lighthouse was also erected.
In 1895 the fort was reinforced with 5 pieces. 30.5 cm. steel hub bits, 12 pcs. 17.0 cm. steel hub bits, 6 pcs. 120 mm quick-firing steel cannons, 7 pcs. 47 mm quick-firing steel guns, 8 pcs. 8 mm double-barred miterrause in the field layer.
During the First World War the fort was reinforced with 3 pcs. of 75 mm quick-firing steel cannons, 1 pcs. of 75 mm quick-firing steel cannon and a 47 mm quick-firing steel cannon in anti-aircraft mounts.
During World War I, the fort was manned by 733 men from the navy.
Remains of the HAWK batteries