Largest Unexploded WWII Bomb Ever Found In Poland Has Detonated Underwater During Defusing Operations

A screenshot of the video showing the Tallboy detonating underwater.

“The deflagration process turned into detonation”.

Tallboy, the biggest unexploded World War II bomb ever found in Poland, dropped by a Royal Air Force Avro Lancaster in 1945, during the raid on the German cruiser Lutzow, has exploded underwater as Polish navy divers tried to defuse it, on Oct. 13, 2020. No one was injured in the explosion.

The weapon was found beneath the Szczecin-Swinoujscie shipping channel, a waterway leading to the port of Szczecinin, in northwestern Poland, during work to deepen the passage, in September 2019.

The activity, the first conducted underwater on a bomb of that size, was carried out by the 41st Mining Divers Group from the 8th Coastal Defense Flotilla.

The initial plan was to disarm the bomb by means of a small explosion but the weapon eventually detonated.

“We were prepared from the beginning that it could happen. The fact that it exploded does not mean that we have failed, quite the contrary. I can definitely say that the entire operation was successful – nobody suffered, neither people nor infrastructure”, said Paweł Rodzoś, director of the Department of Security and Crisis Management at the Medical University of Warsaw, according to the Polish media outlet Onet.

More than 750 people had been evacuated from the surrounding areas and the mine divers were outside of the danger zone at the time of the explosion.

Some residents of Szczecinin felt the blast, but according to the reports no one was hurt during the works. The infrastructure was not damaged either, even though divers will conduct a reconnaissance in the next few hours.

Weighing 12,000 lb (5,400kg – including 2,400kg of explosive), Tallboy was an earthquake bomb developed by the British aeronautical engineer Barnes Wallis. As opposed to conventional bombs, an earthquake or seismic bomb did not explode at or near the surface, and destroy their target directly by explosive force but was designed to be dropped from high altitude so that it could penetrate and explode deep underground, causing intense shockwaves able to damage or destroy targets, such as bridges and viaducts, that would be difficult to hit and destroy with standard bombs.

Royal Air Force Bomber Command, 1942-1945. A 12,000-lb MC deep-penetration bomb (Bomber Command executive codeword ‘Tallboy’) is hoisted from the bomb dump to its carrier at Woodhall Spa, Lincolnshire, to be loaded into an Avro Lancaster of No. 617 Squadron RAF for a raid on the V-weapon site at Wizernes, France. 617 Squadron were unable to bomb the target on this occasion because of low cloud cover, but were to succeed two days later. (Image credit: via Wiki)


About David Cenciotti
David Cenciotti is a journalist based in Rome, Italy. He is the Founder and Editor of “The Aviationist”, one of the world’s most famous and read military aviation blogs. Since 1996, he has written for major worldwide magazines, including Air Forces Monthly, Combat Aircraft, and many others, covering aviation, defense, war, industry, intelligence, crime and cyberwar. He has reported from the U.S., Europe, Australia and Syria, and flown several combat planes with different air forces. He is a former 2nd Lt. of the Italian Air Force, a private pilot and a graduate in Computer Engineering. He has written five books and contributed to many more ones.