What's new
British Ordnance Collectors Network

This is a sample guest message. Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Tallboy found in Poland

LCplCombat

LCplCombat

ORDNANCE APPROVED
Ordnance approved
I can imagine someone asking the EOD team if they can have it after it was made safe.

https://www.bbc.co.uk/news/world-europe-54522203

_114873831_mediaitem114873830.jpg
 
looks like they were trying to detonate it with a small charge in the youtube video,and yet the bbc report says it went off when trying to burn it?
 
Given the quantity of HE in a Tallboy, the size of the explosion doesn't look that great to me (as an unqualified observer!).
 
WARSAW, Poland (AP) — A British World War II bomb exploded while being made safe underwater by navy demolition specialists in northwestern Poland on Tuesday. No one was injured.

The 5.4-ton Tallboy bomb was found in September 2019 beneath a waterway leading to the port of Szczecin during work to deepen the passage. More than 750 people were evacuated for the sappers’ operation since it was located on the southern edge of the popular Baltic Sea resort of Swinoujscie, which like Szczecin was a busy Nazi Germany military port during the war.

Polish navy demolition experts were trying to neutralize it underwater through remote deflagration, which means burning out its explosives, but it went off in the process.
A navy spokesman, Lt. Col. Grzegorz Lewandowski, told The Associated Press that no one was injured since all the sappers were at a safe distance from the blast, which was felt by local residents in Swinoujscie.
“The operation was carried out perfectly and safely and the bomb is safe now,” Lewandowski said.
He noted it was the biggest ever such operation by sappers in Poland, where unexploded wartime bombs, missiles and grenades are still found.
The Tallboy bomb was designed by British aeronautical engineer Barnes Wallis and was used by the Royal Air Force to destroy large Nazi-controlled assets though underground shocks.

The one in Swinoujscie was probably used in April 1945 on the Nazi German battleship Luetzow. Experts don’t know why it failed to explode at the time.
 
Last edited:
As Dreamk's post stated, they had attempted to deflagrate the nominally 5,200 lb (2.359 tonne) loading of Torpex explosive (RDX, TNT, aluminium & wax) the bomb contained.

The attempt failed, what remained of the Torpex loading that hadn't already deflagrated underwent a deflagration to detonation transition (DDT).

If you want to see what its larger brother, the Grand Slam, would do if it went off above ground, try this video.

https://www.britishpathe.com/video/bomb-story/query/ammunition

The video shows the nominally 22,400 lb (10.16 tonne) Grand Slam, which holds about 9,200 lb (4.17 tonnes) of Torpex, being tested on the Foulness Island ranges in Essex in 1950.
 
Eggburt1969 said:
If you want to see what its larger brother, the Grand Slam, would do if it went off above ground, try this video.

https://www.britishpathe.com/video/bomb-story/query/ammunition

The video shows the nominally 22,400 lb (10.16 tonne) Grand Slam, which holds about 9,200 lb (4.17 tonnes) of Torpex, being tested on the Foulness Island ranges in Essex in 1950.
Click to expand...

That's more like the size of explosion I would expect!

I'm a bit surprised that it was tested on the surface, though. Weren't these supposed to be "earthquake bombs", designed to explode deep underground?
 
So I would say that the bomb has fully implemented! That was the full explosive power. No deflagration.
 
Tony Williams said:
That's more like the size of explosion I would expect!

I'm a bit surprised that it was tested on the surface, though. Weren't these supposed to be "earthquake bombs", designed to explode deep underground?
Click to expand...

Yes, I wouldn't like to hazard a guess at the fragmentation danger area? Rather large I'd image. Plus the acoustic forecast map must have been quite interesting to see. You'd certainly not want any cloud cover present when it went off.

As to why it was tested on the surface. This was a fragmentation test (arena) of the bomb, so not designed to measure its cratering or cavity-forming (camouflet) capabilities. As such the steel plates are used to measure the penetration capability and the distribution of the fragments at various distances. The plate are numbered so they are easier to figure where they came from, the blast projecting them quite a distance from the bomb's detonation point. The copper wire short-circuit screens seen attached to the wooden 'wall' would have been to measure the average velocity (the time of flight) and distribution of the fragments at that distance. The thicker steel plates and sandbags in front of the velocity screens act as a fragment ricochet (skip) barrier, so only 'straight-line (-path)' fragments strike the screens. The thick plates also measure the penetration capability and the distribution of the fragments at that distance.

I remember talking to a person from the photography department and he said there was also high-speed cinematography of the bomb being detonated in a vertical orientation. The speed (frame rate and exposure time) of the cameras such that the bomb can be seen to expand like a balloon and then start to fragment, the detonation product gases then venting through the fragmenting casing of the bomb. I didn't get to see that unfortunately.

As the the earthquake bit. The Tallboy and Grand Slam were designed to destroy their initial intended targets by a combination of ground shock and camouflet (or crater) formed. The latter undermining the foundations of the structure, leading to its collapse. When dropped on ships the important effects depend on if its a direct hit, or the bomb goes off in the water. For the former the penetration capability of the bomb body itself, and then the fragmentation and blast effects on the target. For underwater bursts, primary the shockwave and bubble energy of the detonation product gases are important. For direct hits on bunkers, though the bomb wasn't really desinged for this, the effect of its fragments and blast on the objects within the structure are of primary importance if it makes it through. If it doesn't, then the effect of its detonation within the protective structure, i.e. does it cause the structure to fail through the transmitted shock and its high pressure detonation products.
 
Last edited:
The TV news confirms that the deflagration failed.:tinysmile_cry_t3: The bomb has implemented its full force.
 
You must log in or register to reply here.
Top