Diagram of defenses
Casemates are blasted out of island's rocky sides, and mount a single 130mm/55 gun. The port/seaplane base at the northern
end of the island is defended by 4 130mm/55 in two twin turrets.
Battery Gangut and Battery Admiral Apraxin are on the island's plateau, and consist of reinforced concrete installations
mounting six 305mm/52 guns in two triple turrets, and are shown below:
Battery Peter Veliki will consist of four 42cm/53 guns in two twin turrets. It will be located 1 km southeast of airfield,
and construction began in August 1925. Guns and turrets were completed in December 1925, and will be installed during 1926.
On the mainland, at Naukan and Nunyamo, are installations using the guns and fire control equipment of the battleship Petropavlovsk,
each mounting 6 305mm/52 in two triple turrets and 8 130mm/55 in casemate mounts. These installations are similar in design
to those found on Big Diomede Island.