Dora Supergun 80cm

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HEINRICH HOFFMANN/BAYERISCHE STAATSBIBLIOTHEK/BILDARCHIV PREUSSISCHER KULTURBESITZ/ART RESOURCE, NEW YORK

Fully assembled, the massive Krupp-built 80cm gun was so heavy it was transported on two sets of special parallel railroad tracks.

DAYS OF

Thunder The making of Dora, the world’s biggest gun by C. G. Sweeting

Zehn, neun, acht.…The countdown for Dora’s first shot in anger had begun. Sieben, sechs, fünf….Colonel General Erich von Manstein, commander of the German Eleventh Army, accompanied by Marshal Ion Antonescu, Romanian head of state and armed forces commander, checked their earplugs and waited expectantly in the observation post over a mile from the enormous railway gun. Vier, drei, zwei….Silence prevailed. Feuer!….KABOOM! The thunderous roar was followed by a huge cloud of smoke; the air tingled and the earth shook as the 4.8ton projectile whistled in a high trajectory toward its designated target 15.5 miles distant. It may have resembled a fire-breathing monster from Norse mythology, but this was no myth. “Dora” was the biggest gun of all time, and it was firing at the port city of Sevastopol, then the world’s strongest fortress.

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ora’s entry to action on June 5, 1942, marked the culmination of a program that began six years earlier when Adolf Hitler first discussed the construction of a giant cannon with officials of the Krupp factory. Hitler was determined to rearm Germany and establish hegemony over Europe, and he realized that his audacious plan could result in war with France, Germany’s perennial enemy. France was constructing a series of massive fortifications, the Maginot Line, along the Franco-German border, and Hitler wanted extremely heavy artillery capable of destroying even the strongest forts.

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Hitler liked to think big, and he thought a supergun would be an important addition to Germany’s new arsenal. Krupp immediately commenced initial design work on its own initiative. The German Army Ordnance Office (the Heereswaffenamt) issued a development contract to the firm of Friedrich Krupp of Essen in early 1937 calling for the design and development of an enormous 80cm kanone eisenbahngeschütz, or railway gun. The design and production of this gun, carriage, and special ammunition would challenge the state of the art in metallurgy, ballistics, and mechanics, and would require new procedures in the operational use of heavy artillery. Dr. Erich Müller was selected to supervise the construction of the biggest gun ever built. Often called Kanonen-Müller because of his accomplishments in artillery design, he assembled a team of experts, and the entire development and manufacturing program was conducted in secret. The gun was originally called the “Gustav Gerät” (Gustav Equipment) and later “Schwerer Gustav” (Heavy or Fat Gustav) after the former head of the Krupp firm, Gustav Krupp von Bohlen und Halbach. When finally delivered in early 1942, it was given the cover name “Dora,” and was sometimes referred to in documents as the “D-Gerät.” The different names later caused confusion about how many superguns were built and deployed. The gun was planned to weigh approximately 1,170 tons and to have a range of about 25 miles when the barrel was elevated to 45 degrees. First estimates suggested a barrel life of 100 rounds. The special projectiles had to be able to penetrate at least 18 feet of the strongest type of steel-reinforced concrete fortification. Not since the famous 21cm “Paris Gun” that bombarded the French capital in 1918 from a distance of 72 miles had a weapon of this size been planned. A large team of designers, engineers, and technicians were employed not only to research and design the gun and carriage but to develop special cranes for the assembly and disassembly of the gun, special ammunition and equipment, and special rail cars to transport the components. And when loaded, each car had to be light enough to travel over existing bridges. Large steam locomotives could be used for moving the gun over long distances, but a special engine had to be designed and built to maneuver the gun precisely for firing. Conventional electric engines were not powerful enough; regular steam locomotives burned coal and thus would be impractical for maneuvering the gun at the front, since smoke and steam would belch high into the air and invite attack. A special dieselelectric locomotive of about 1,000 horsepower was designed not only to maneuver the gun for aiming but to provide the electrical power needed to elevate the gun barrel and operate the other electric and hydraulic components and accessories. Two engines were ordered for each of the three guns planned, and the design of the engines and the railroad cars had to

be coordinated with the Deutsche Reichsbahn, the national railway system. In 1939 the German ordnance office placed an order with Krupp for three complete guns. Construction began immediately, and detailed progress reports had to be submitted periodically to Hitler. In anticipation of the production contract, Krupp had already begun fabricating components of the gun, its carriage and accessories.

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itler achieved several bloodless political successes in Europe during the 1930s, at the same time building a powerful war machine that threatened and intimidated his neighbors. His most audacious demand was the return of the corridor to the sea that had been given to Poland by the Treaty of Versailles after World War I, the swath of land separating East Prussia from the rest of Germany. When Poland refused Hitler’s demand, he invaded on September 1, 1939, and World War II began on September 3, when Great Britain and France declared war on Germany. Hitler wanted to attack France immediately, but the redeployment of the Wehrmacht and the onset of winter weather delayed his invasion of the West until the following spring. An army of skilled Krupp workers was already toiling around the clock, producing various weapons of war, but the three giant rail guns were far from completion when the German Blitzkrieg in the west began on May 10, 1940. The Dora guns were not needed for that, because the German army bypassed the Maginot Line fortifications, striking through the rugged Ardennes region. And with the fall of France and Belgium there were no more fortifications in the west to bombard with the powerful new weapon. The construction of the complex components of the Dora gun continued in the cavernous shops of Krupp: the huge steel carriage, the gun cradle, the horizontal sliding breechblock of finest steel, and the massive two-part 80cm barrel, just over 95 feet long. Large hydraulic and electrical systems were also designed and produced. The platform for the crew serving the gun was fitted on the upper portion of the firing carriage. The lower portion of the firing carriage was supported on two twin-bogie units, each fitted with five two-wheeled axles. The gun, when assembled and ready for action, was designed to run on two parallel tracks, or four rails. Two 10-ton cranes were built to assemble the gun in the field. During this time, special railway cars were also developed and built for transporting the entire weapon system. In traveling position, the equipment ran on a normal European gauge railway track. The entire program was a challenging management job even for the experienced Krupp specialists, as well as for ordnance and electrical and railway engineers. Crewmen who had previous railway gun and heavy artillery experience were selected in early 1941 and trained on smaller guns to be

Projectiles had to be able to penetrate 18 feet of concrete

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HEINRICH HOFFMANN/BAYERISCHE STAATSBIBLIOTHEK/BILDARCHIV PREUSSISCHER KULTURBESITZ/ART RESOURCE, NEW YORK

Adolf Hitler—who had sought extremely heavy artillery in the 1930s as part of his buildup of German armed forces—with other top Nazis, pays a visit to a test site in Rügenwalde, Germany, in April, 1943 to inspect the Dora gun and its 4.8-ton explosive projectile.

ready for testing and deploying the superguns. The design and fabrication of the special ammunition proceeded concurrently with the manufacture of the guns and rail cars. The ammunition consisted of a projectile, a shell case with charge, and bagged powder. Two types of shells were developed: A high-explosive projectile weighing 4.8 tons and a special armored shell—a concrete-penetrating projectile of chrome-nickel steel with an especially hard point. It had a streamlined, pointed cover for aerodynamic purposes and contained 550 pounds of high explosive with a base fuze. This shell was designed to pierce fortifications and explode inside. It had a length of 94.5 inches and weighed 7.1 tons—probably the heaviest artillery shell ever built. Initial test firings showed the maximum range with the high-explosive shell to be over 29 miles and a range of about 23.6 miles with the concrete-busting projectile. The range was later improved through continued experiments. A study by the U.S. Army Ordnance Department of shells found on a test range in Bavaria in 1945 states the steel shell had a hollow, thick-walled body 3.5 meters (11.5 feet) long and a diameter of 80 centimeters (31.5 inches). The projectiles were transported in heavy wooden crates in a horizontal position on flat cars or in ammunition cars. The powerful propellant was contained in the metal shell case and two additional propellant charges. The one-piece shell case was made of steel, plated with brass, manufactured in 1942, and marked with the secret manufacturer’s code “bwn,” indicating the firm of Friedrich Krupp A.-G., Essen. The two separate propellant charges in white cylindrical bags were carried in wooden boxes marked with the manufacturer’s

code “dbg,” indicating that they were made by Dynamit A.-G., Alfred Nobel & Co., Werk Düneberg. The weight of the three propellant charges was 2,500 pounds. According to the U.S. Army report, the muzzle velocity of the gun was 2,500 feet per second. Hitler’s main objective at this time was the conquest of the Soviet Union. He meant to invade Russia without warning in the spring of 1941 in order to remove the threat of Soviet attack and to secure for Germany the oil, labor, wheat, and other resources that he hoped would make the Reich invincible. But unexpected fighting in the Balkans delayed his attack on Russia. The German attack finally began on June 22, 1941, when three army groups, with Luftwaffe support, launched Operation Barbarossa. Army Group North fought through the Baltic States toward Leningrad, Army Group Center struck east toward Moscow, while Army Group South, with the Romanian army, headed toward Kiev and across southern Russia. By September the German Eleventh Army, under the command of General Erich von Manstein, part of Army Group South, was battling its way through the heavily defended Perekop Isthmus, the entrance to the Crimean peninsula. The Soviets were driven to the east and off the peninsula, allowing Manstein to begin a siege of the port city of Sevastopol, home of the Soviet Black Sea Fleet. The area around Sevastopol was protected by mountains in the south and hills and rough country to the east, with the flatter northern sector the logical area for a major attack. But this sector was heavily defended with concrete forts, some with turrets armed with artillery like that of the Russian battleships offshore. The Germans brought up aircraft and artillery of all types to help soften up

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riedly constructed at the end of a new railway spur behind the northern front near the city of Bakhchisaray. This was the assembly area for Dora, where over 2,500 men began to put the gun together. Its firing position, just south of the assembly area, was created by cutting through a small hill and building a curved section of double track. Two diesel-electric locomotives maneuvered the 25 railcars carrying the compoy the spring of 1942 more German heavy artillery nents of the gun into the assembly area. After the major parts and ammunition were arriving on the railway that were assembled, the accessories were installed: platforms and had been rebuilt to the Sevastopol area. Romanian ladders for the crew and elevators for the projectiles, powder army units were deployed along the eastern side of bags, and shell cases. The gun was almost two stories high the siege perimeter, and although no tanks were provided, when fully assembled, a complex task performed in just over the German infantry divisions were fully equipped with three weeks by about 250 engineers, artillerymen, railway self-propelled assault guns (sturmgeschütz), most armed with troops, and Krupp technicians. Ammunition was brought up 75mm cannons. The VIII Fliegerkorps, the most powerful in the special cars, camouflage nets erected, and antiaircraft ground attack formation in the Luftwaffe, joined the attack. guns positioned. A small detachment from “Harko,” the 306 Höheres Artillerie Kommandeur, the army unit directing the Preparations were intense on both sides of the Sevastopol siege artillery bombardment of Sevastopol, was established near line. The Soviets had used the previous months to bring in Dora. The big gun was ready for action. reinforcements and prepare more field fortifications, includGeneral Manstein gave the order to launch the offensive, and ing trenches, barbed wire entanglements, mines, antitank before dawn on June 2, 1942, the sky lit up and the roar of exploditches, and pillboxes. sions echoed across the area as the German artillery barrage The heavy traffic on the railroad to Sevastopol included struck the Soviet fortifications. The intense bombardment trains with large items of German equipment covered with continued around the clock causing great damage to Soviet tarpaulins. A small rail yard with double tracks was hurdefenses and communications, Ger man infantry and combat engineers, supported by assault guns and dive-bombers, advanced along the northern front in fierce fighting. Early on June 5, the two special locomotives eased Dora onto the newly built, curved section of double track facing Sevastopol. Ammunition was moved forward and everyone, including Manstein and Antonescu, waited impatiently for the order to load and commence firing. Lieutenant Colonel Robert Böhm, the unit commander, whose command post was 1.2 miles from Dora, checked the details of the previously selected targets. Lieutenant Colonel Knoll, the gun captain, and his crew of 450 men, were ready and in place. Because the gun and railway cars remained vulnerable to Soviet attack, flak guns and smoke generators were positioned around the wellguarded area. Harko notified Böhm to prepare for firing, and Knoll began the loading and firing procedure. The targets were a Soviet barracks block and fortified artillery batteries along the coast, some 15.5 miles distant, out of range of other German artillery. At 5:35 a.m. the order to fire was given to the gun captain, who began the countdown on this first shot. First fired in anger in June 1942 during the German siege of Sevastopol, Crimea, Dora targeted Feuer! The bright flash and thunderous otherwise unreachable Soviet fortifications with fearsome power—but middling accuracy. these defenses and support the fierce struggle to break through the fortifications. After significant gains, the siege had to be suspended when the Soviets made a landing in the east of the Crimean Peninsula, resulting in months of battle before the Russians were again defeated and ejected, allowing the siege of Sevastopol to resume.

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BAKER VAIL

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HEINRICH HOFFMANN/BAYERISCHE STAATSBIBLIOTHEK/BILDARCHIV PREUSSISCHER KULTURBESITZ/ART RESOURCE, NEW YORK

Supergun in action: A thunderclap explosion and a cloud of smoke erupt as demonstration and test rounds are fired at the facility at Rügenwalde before an audience of Nazi leaders and other observers.

roar was unlike that produced by any artillery shot Manstein and the other observers could remember. The recoil of the gun shook even its massive carriage, but all components functioned properly. A flight of Luftwaffe observation planes was assigned to cooperate with Dora and report the results of the firing by radio to Harko and Böhm. Tensions mounted as the seconds ticked past. Then—a hit, sending a pillar of smoke and dust climbing high into the morning sky. When the report reached Knoll’s crew, a cheer went up from the men who had spent months training and working for this moment. There was no time to celebrate, because eight more rounds were ordered fired at Soviet coastal batteries and Fort Maxim Gorki I. Those shells reached the targets and did some damage, although most fell short of or beyond the target, destroying field fortifications and hurling mangled bodies high into the air. That afternoon six rounds were fired at another important target, Fort Stalin, again with mixed results. One round was a direct hit, and a 90-foot-wide crater was reported. Other craters observed during the siege were about 50 feet deep and some up to 100 feet, exploding far underground. Manstein, Antonescu, Alfried Krupp, and Dr. Erich Müller of Krupp, witnessed the firing of several rounds. Firing commenced the next morning with seven rounds aimed at Fort Molotov, again with mixed results. An important

new target was selected for that afternoon: A major Soviet underground ammunition storage facility had been identified through aerial reconnaissance and interrogation of prisoners and deserters. Called the Weisse Klippe or Munitionsberg (White Cliff or Ammunition Mountain) by the Germans, it was thought by the Russians to be immune to attack, because it was in a large cavern under a hill facing, and partly under, Severnaya Bay, far inland on the northern shore. Heavy steel doors protected the hillside entrance and it was, in fact, invulnerable to aerial bombardment and conventional artillery. This was a job for Dora. Again, the locomotives positioned Dora to aim at the distant target. Seventeen rounds were fired at the mountain; the first nine rounds of concrete-busting shells struck with great success, including six direct hits. Firing began again on June 7, with more of the huge shells striking the mountainside and throwing up large clouds of dirt and rocks. Three rounds were direct hits, and at least one evidently punched through the last 90 feet of earth and rock and exploded inside the ammunition storage chamber. The result was a tremendous thunderclap blast, with secondary explosions adding to the destruction. Witnesses stated that the explosion was like a volcanic eruption, with a huge plume of smoke soaring high into the sky. It was felt and heard for many miles, especially

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across the bay in Sevastopol. The loss of ammunition at this critical time in the siege weakened the Red Army’s ability to defend Sevastopol. Strangely, though, when Hitler learned of this, he sent an angry message to Manstein directing that Dora be used only against concrete fortresses. On June 11 Dora bombarded another Soviet strongpoint, Fort Siberia, with five rounds, and three direct hits caused massive damage, rendering it vulnerable to ground attack. Dora continued to roar periodically until June 17, targeting several forts, including Fort Maxim Gorki II. The five rounds blasting that modern fort softened it up for the coming ground attack. A total of 48 concrete-penetrating rounds were fired by Dora during the siege, and the gun and its crew performed well, with only minor mechanical problems. Five high-explosive shells were reportedly fired on June 25, the one against Sevastopol itself causing a large column of smoke to rise over the city. The explosion of shells from Dora and other German heavy artillery had a considerable effect on the Russians’ morale, often bursting the soldiers’ blood vessels even if it did not kill them with fragments or flying debris. The drastic changes in air pressure from the explosions also ruptured eardrums and sometimes lungs of soldiers in the concrete chambers and

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corridors. Fear and terror, or panic, often ensued. After the capture of the fortresses and the fall of Sevastopol, Dora was disassembled, loaded on railcars, and, on orders from Hitler, moved to Army Group North for the bombardment of Leningrad. But because of a Soviet offensive, it was instead dismantled and returned to the test range at Rügenwalde, Germany (now Darłowo, Poland). There it was serviced and a new barrel installed. Dora remained under camouflage at Rügenwalde where it was joined by Schwerer Gustav 2, the other completed 80cm railway gun. Both were used for testing and experiments with new longer-range ammunition. Dora and Schwerer Gustav 2 remained ready for action until late in the war but the march of events made their further use impractical. By 1945, Dora was still at the test range, while Schwerer Gustav 2 had been moved to near Chemnitz in eastern Germany, where it was overrun by the advancing Russians. At some point the Germans destroyed Dora and scattered the remains along a rail line near Grafenwöhr, a German training ground in Bavaria, where they were recovered by Allied forces. MHQ C. G. Sweeting is the author of several books, including Hitler’s Personal Pilot: The Life and Times of Hans Bauer.

ARCHIV HEINRICH HOFFMANN/BAYERISCHE STAATSBIBLIOTHEK/BILDARCHIV PREUSSISCHER KULTURBESITZ/ART RESOURCE, NEW YORK

Soviet strongpoints around Sevastopol, such as Fort Maxim Gorki I shown here, were subjected to heavy artillery fire, including rounds from Dora. Aerial bombardment by German Fliegerkorps VIII added to the destruction—a prelude to the ground assault that captured the city on July 1.