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(Basil) - onetrack, would I be correct in guessing that the shock wave advances at about M1.0 but the initial speed of the fragments would be in excess of M10.0?
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tdracer - Many types of explosive are quite stable over a long period of time - however some types do decompose into more unstable forms and become very dangerous to move after decades of inactivity.
Amatol is a mixture of TNT and ammonium nitrate and is therefore relatively stable. I won't go into the fine details, there are too many suspicions raised if you access anarchy sites, and instructions on composition and manufacture of explosives.
Yes, the de-activated bomb is removed from the site and taken to the likes of a weaponry range for destruction by a suitable small initiating explosive.
The important factors are precisely identifying the model of munition, obtaining the technical specifications of the munition (nearly all types of military munitions specs are still on record) - and most importantly, identifying any "anti-handling" devices that are likely to have been fitted. "Anti-handling devices" are those devious devices designed to kill anyone trying to de-activate the munition, and they can be exceptionally dangerous.
In SVN, M16 anti-personnel mines ("jumping jacks") were often placed in the ground with a hand grenade set below the M16 casing with the pin removed.
The fly-off handle of the grenade would be retained in position, thus keeping the spring-loaded striker from initiating the activation of the grenade.
Unwary sappers would de-activate the M16 fuze (a relatively simple operation), then lift the M16 from its resting place in the ground, and "BOOM" - the unwary sapper was often seriously injured, and occasionally killed, by the grenade going off, once the pressure came off it.
Amatol is a mixture of TNT and ammonium nitrate and is therefore relatively stable. I won't go into the fine details, there are too many suspicions raised if you access anarchy sites, and instructions on composition and manufacture of explosives.
Yes, the de-activated bomb is removed from the site and taken to the likes of a weaponry range for destruction by a suitable small initiating explosive.
The important factors are precisely identifying the model of munition, obtaining the technical specifications of the munition (nearly all types of military munitions specs are still on record) - and most importantly, identifying any "anti-handling" devices that are likely to have been fitted. "Anti-handling devices" are those devious devices designed to kill anyone trying to de-activate the munition, and they can be exceptionally dangerous.
In SVN, M16 anti-personnel mines ("jumping jacks") were often placed in the ground with a hand grenade set below the M16 casing with the pin removed.
The fly-off handle of the grenade would be retained in position, thus keeping the spring-loaded striker from initiating the activation of the grenade.
Unwary sappers would de-activate the M16 fuze (a relatively simple operation), then lift the M16 from its resting place in the ground, and "BOOM" - the unwary sapper was often seriously injured, and occasionally killed, by the grenade going off, once the pressure came off it.
Last edited by onetrack; 28th Dec 2016 at 07:02.
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One track, same era, same effect, was a Mills bomb or similar in a drinks can. Picked up as FOD
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I believe the Vietcong would defuse an unexploded USAF bomb, light a fire underneath it and capture the resulting liquid explosive (possibly Ammonium Nitrate but I don't know) to use in their own devices...
Ammonium Nitrate is very stable on it's own, but detonate it.....
Ammonium Nitrate is very stable on it's own, but detonate it.....
BBC 4 has on old (1974) programme available about Bomb Disposal..
BBC iPlayer - Tuesday Documentary - The Bomb Disposal Men
BBC iPlayer - Tuesday Documentary - The Bomb Disposal Men
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Thank you folks, this has turned into a really interesting ( and educational ) thread.
Just a pedant's question: are they fuzes or pistols? My thinking is pistol, but I can't remember the type.
PN is on the right track with the motorcycle story. There are tools that can be used remotely to remove a fuze/pistol. The IGOL (I Go On Living) dates from WW2; it is a circular device that is clamped to the fuze and two sprung 'hammers' are operated by a long cord (very long!). The IGOL was superseded by the Rocket Wrench. Imagine a Catherine Wheel clamped to the fuze and fired by two 0.5in electrically fired cartridges mounted opposite each other. The fuze is spun out and a bungee attached to a stake pulls it clear. The German EOD guys are hugely experienced and no doubt had their own methods. I just hope it was not the way an American 20lb Frag bomb was tackled when uncovered at Gutersloh. As per the protocol the German EOD was informed and were escorted to the site. I did not witness the render safe as when one of the men produced a hammer and chisel I found I had urgent business a couple of hundred meters away. But it worked, and I expect they had done it dozens of times.
PN is on the right track with the motorcycle story. There are tools that can be used remotely to remove a fuze/pistol. The IGOL (I Go On Living) dates from WW2; it is a circular device that is clamped to the fuze and two sprung 'hammers' are operated by a long cord (very long!). The IGOL was superseded by the Rocket Wrench. Imagine a Catherine Wheel clamped to the fuze and fired by two 0.5in electrically fired cartridges mounted opposite each other. The fuze is spun out and a bungee attached to a stake pulls it clear. The German EOD guys are hugely experienced and no doubt had their own methods. I just hope it was not the way an American 20lb Frag bomb was tackled when uncovered at Gutersloh. As per the protocol the German EOD was informed and were escorted to the site. I did not witness the render safe as when one of the men produced a hammer and chisel I found I had urgent business a couple of hundred meters away. But it worked, and I expect they had done it dozens of times.
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I've never forgotten the captured NVA film we were shown at the School of Military Engineering in Casula, NSW, in 1970.
This film recorded an NVA sapper finding an unexploded U.S. bomb, defuzing it - then cutting around 7/8ths of the circumference of the casing with a hacksaw, leaving around 1/8" to 1/16" (3 - 1.6mm) casing thickness - then tapping the bomb with a sledgehammer to break it apart, so the NVA sappers could dig out the explosive by hand to fabricate crude booby traps, mines and hand grenades of their own.
These blokes even had little jungle foundries going, smelting the U.S. bomb casings to form them into their own hand grenades, using their own grenade casting molds!
The incredible part about the NVA effort is understanding that the U.S. bombs not only had anti-withdrawal mechanisms designed to kill the untrained person trying to withdraw the fuze - they also often had time-delay fuzes, activated by slow-working chemicals, that would also lead to "failed" bombs unexpectedly going off, up to 144 hrs after they were dropped!
This film recorded an NVA sapper finding an unexploded U.S. bomb, defuzing it - then cutting around 7/8ths of the circumference of the casing with a hacksaw, leaving around 1/8" to 1/16" (3 - 1.6mm) casing thickness - then tapping the bomb with a sledgehammer to break it apart, so the NVA sappers could dig out the explosive by hand to fabricate crude booby traps, mines and hand grenades of their own.
These blokes even had little jungle foundries going, smelting the U.S. bomb casings to form them into their own hand grenades, using their own grenade casting molds!
The incredible part about the NVA effort is understanding that the U.S. bombs not only had anti-withdrawal mechanisms designed to kill the untrained person trying to withdraw the fuze - they also often had time-delay fuzes, activated by slow-working chemicals, that would also lead to "failed" bombs unexpectedly going off, up to 144 hrs after they were dropped!
Allied forces developed their own designs of anti-handling devices during World War II. For example, the American M123A1, M124A1, M125 and M131 series of chemical long delay tail-fuzes which were used in air-dropped bombs, starting around late 1942 and remaining in service until the 1960s.
Frequently fitted to M64 (500 lb), M65 (1000 lb) and M66 (2000 lb) general-purpose bombs, these fuzes were primarily designed to operate as chemical long-delay fuzes, with settings ranging between 15 minutes and 144 hours.
The time delay mechanism was simple but effective: after being dropped from the aircraft a small propellor at the rear of the bomb revolved, gradually screwing a metal rod into the fuze, crushing an ampoule of acetone solvent contained within it.
When this happened the fuze was fully armed and the timer countdown had started. The acetone soaked into an absorbent pad next to a celluloid disk which held back a spring-loaded firing pin from a percussion cap connected to an adjacent detonator.
Acetone slowly dissolved the celluloid disk, gradually weakening it until the cocked firing pin was released and the bomb detonated.
The time delay of the fuze varied according to the acetone concentration and the thickness of the celluloid disk.
Removing a chemical long delay fuze from a bomb after it had been dropped would have been a straightforward process had it not been for the fact that there was an integral anti-withdrawal mechanism designed to kill anyone who tried to render the bomb safe.
Fuzes such as the M123 (and its derivatives) contained two small ball-bearings at the lower end which slid out of recesses when the fuze was screwed into the bomb by aircraft armorers.
The ball-bearings jammed into the screw-threads inside the fuze well, preventing the fuze from being removed. Because the lower end of the fuze was locked in place deep inside the bomb (where it was hard get at) this posed major problems for enemy EOD personnel.
Attempting to unscrew a fully armed chemical long-delay fuze caused it to split into two separate fuze assemblies.
This action automatically triggered detonation by releasing the cocked firing pin in the lower fuze assembly, with lethal results for anyone nearby.
Frequently fitted to M64 (500 lb), M65 (1000 lb) and M66 (2000 lb) general-purpose bombs, these fuzes were primarily designed to operate as chemical long-delay fuzes, with settings ranging between 15 minutes and 144 hours.
The time delay mechanism was simple but effective: after being dropped from the aircraft a small propellor at the rear of the bomb revolved, gradually screwing a metal rod into the fuze, crushing an ampoule of acetone solvent contained within it.
When this happened the fuze was fully armed and the timer countdown had started. The acetone soaked into an absorbent pad next to a celluloid disk which held back a spring-loaded firing pin from a percussion cap connected to an adjacent detonator.
Acetone slowly dissolved the celluloid disk, gradually weakening it until the cocked firing pin was released and the bomb detonated.
The time delay of the fuze varied according to the acetone concentration and the thickness of the celluloid disk.
Removing a chemical long delay fuze from a bomb after it had been dropped would have been a straightforward process had it not been for the fact that there was an integral anti-withdrawal mechanism designed to kill anyone who tried to render the bomb safe.
Fuzes such as the M123 (and its derivatives) contained two small ball-bearings at the lower end which slid out of recesses when the fuze was screwed into the bomb by aircraft armorers.
The ball-bearings jammed into the screw-threads inside the fuze well, preventing the fuze from being removed. Because the lower end of the fuze was locked in place deep inside the bomb (where it was hard get at) this posed major problems for enemy EOD personnel.
Attempting to unscrew a fully armed chemical long-delay fuze caused it to split into two separate fuze assemblies.
This action automatically triggered detonation by releasing the cocked firing pin in the lower fuze assembly, with lethal results for anyone nearby.
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The problem is in Vietnam something like 10% of bombs dropped failed to explode, at all.
Tonnage dropped apparently exceeded 5 million tons (including who knows how many millions of cluster bomblets that were notorious for failing), implying 500,000 tons of unexploded munitions, explaining why to this day people are still being killed/ maimed in Vietnam and Laos....
So I guess the enemy had lots of "dud" bombs to work with...
Tonnage dropped apparently exceeded 5 million tons (including who knows how many millions of cluster bomblets that were notorious for failing), implying 500,000 tons of unexploded munitions, explaining why to this day people are still being killed/ maimed in Vietnam and Laos....
So I guess the enemy had lots of "dud" bombs to work with...
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Another SVN veteran told me a few years ago, that an average of 7 people a day were still being killed in Vietnam by unexploded ordnance left over from the Vietnam War.
I'm not sure where he got his information from, but the article below says over 40,000 Vietnamese have been killed by unexploded ordnance in Vietnam since 1975.
If we call it 41,000 deaths, that's 1000 deaths a year in the 41 years since 1975. There's possibly quite a few unrecorded deaths as well.
1000 deaths a year is still 2.73 people being killed every day there, and it doesn't seem like the casualty rate is slowing down much.
The Vietnam War is still killing people
I'm not sure where he got his information from, but the article below says over 40,000 Vietnamese have been killed by unexploded ordnance in Vietnam since 1975.
If we call it 41,000 deaths, that's 1000 deaths a year in the 41 years since 1975. There's possibly quite a few unrecorded deaths as well.
1000 deaths a year is still 2.73 people being killed every day there, and it doesn't seem like the casualty rate is slowing down much.
The Vietnam War is still killing people
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One track, during Confrontation we had 3 DA per stick of 21. Roughly #19 an #17 had 60 min and 30 min respectively. They would have been about 140 yards apart. Then #3 had a 6 hr delay. The other 18 were set for airburst. Nasty, especially given probable error of up to 2000 yards.
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The British Ordinance collectors network (BOCN)
Has a fascinating web site and forum packed with info, and populated. by
collectors and disposal (EOD) people from around world.
A friendly site, well worth a few hours,or days in my case.
The site is down as of now,but temporarily.
Has a fascinating web site and forum packed with info, and populated. by
collectors and disposal (EOD) people from around world.
A friendly site, well worth a few hours,or days in my case.
The site is down as of now,but temporarily.
