Details Sketchy On How Tank Was Breached

The Columbus Dispatch | June 3, 2004 | By Tim Doulin

[mark502inf]

The M1A1 Abrams tank to which Pfc. Nicholaus E. Zimmer was assigned was designed with the purpose of preserving the lives of crew members.

But Zimmer was killed when the tank came under attack Sunday from rocket-propelled grenades, which should not have been able to penetrate the tank's armor.

Details of the attack and how Zimmer, of southern Delaware County, died were sketchy yesterday.

"We know it was RPGs and he was assigned to a tank, and the tank came under attack," said Cathy Gramling, a Defense Department spokeswoman.

"But we don't know the circumstances."

Zimmer could have been struck if his body had been exposed, Gramling said. He also could have been inside the tank and died from a "percussion" injury when the grenade round hit the tank.

Zimmer's family said they were told by the Army that Zimmer likely was inside the tank when it was struck and that two others were injured.

"The No. 1 goal in designing that tank in the 1970s was survivability of the crew," said George F. Hofmann, military historian at the University of Cincinnati.

Hofmann wouldn't speculate on what caused Zimmer's death. He said an RPG7, which is typically used by Iraqi insurgents, is unlikely to penetrate an Abrams.

"If there was a penetration, then the terrorists we are dealing with have introduced a much more powerful RPG," Hofmann said. "But I am just speculating."

The tank's armor is composed of depleted uranium, which has a density 2 1/2 times greater than steel.

"It is supposed to even be able to repel any type of round that comes from another tank," said Hofmann, who served as an Army instructor and cadre in the Special Training Regiment at the U.S. Armor Training Center in Fort Knox, Ky.

He said the tank is "compartmentalized."

"If a round by chance penetrates, you have compartments that protect other crew members."

[JasonC]

"The tank's armor is composed of depleted uranium"

No, the tank's armor is mostly steel, but includes layers of DU - as well as cermanic layers in titanium mesh - to vary the concentration along the path of a potential penetration, etc. It is not "composed of" DU, which would imply it is made of DU and nothing else.

"It is supposed to even be able to repel any type of round that comes from another tank"

No, physically impossible. The ceramic layering is meant to defeat many smaller HEAT rounds, and the DU layering is meant to defeat plain AP and some high velocity long rod penetrators, at some ranges, and against the thickest frontal plates. A T-72 round can be stopped at 1 km. But from the side it would go in. And the best modern tanks would penetrate even from the front it close enough.

Tanks are not meant to be invulnerable. They are meant to be well protected against many common weapons. This reduces the number of enemy weapons that can hurt them, and allows them to focus on those and outshoot them. Against everything else, they can shoot them with impunity. That is what creates the tactical effect sought when using tanks.

There is nothing surprising in *enough* AT rounds - even simple HEAT rounds - managing to knock one out. When the part of the tank hit is not specified or when the tank is hit repeatedly in the same place, there isn't much to explain. It would be outstanding if any number produced no effect, but it is not the design standard the tank is held to.

[Thud]

ping

[Squantos]

Agree.......the 7V is awesome, cheap and plentyful in numbers. A good tank killer team armed with such is to be worried about by future designers of armor......

Stay Safe !

[aegiscg47]

I doubt it was a Kornet as they're not suitable for street fighting. It could be a variant of the RPG-7/14 with one of the new tandem top attack warheads. I believe this is why they created the armored vents for the M-1s engine last year as they were vulnerable to top attack warheads. This is the new trend for the rest of the world(we've been using TA warheads for awhile), so hopefully the U.S. Army will come up with a countermeasure.

[LuigiBasco]

Fox and that's about it period. May be some local print media, but the great preponderance of the media will see this country drown before they tell the American people the truth about just what is going on in the world. They have their own political agenda. A good example is: when was the last time you heard or read of all the good work being accomplished in Iraq? Name just two please.

[Poohbah]

The HV would not be fired off the shoulder...but its launch could be masked by RPG attack...just like the Kornet attack could be which I find more plausible anyway.

OK, so you're talking about a tube the size of a MBT gun, getting wheeled around...

Ahem, even the Army would tend to notice such things...

[Neanderthal]

"The missile's warhead can penetrate 1200 mm of armor"

1200 mm is almost 4 feet. That's pretty thick armor.

[Sundog]

they did figure it out. It was a French anti-tank weapon, unknown how one rocket got into Iraqi hands. Sorry I don't have a source for you. It put a pencil-sized slug of uranium through the armor. The French had sold that munition to a few east-european governments tho.

[Blood of Tyrants]

I defer to Jeff's expertise on this.

[Tallguy]

1200 mm is almost 4 feet. That's pretty thick armor.

At the risk of telling you something you may already know, 1200 mm is the equivalent thickness of the chobham armor, ie. as if the armor were made solely of Rolled Homogeonous Steel. It's not actually 1200 mm...

[Lion Den Dan]

<<"It is supposed to even be able to repel any type of round that comes from another tank," said Hofmann, who served as an Army instructor and cadre in the Special Training Regiment at the U.S. Armor Training Center in Fort Knox, Ky. <<<

I've been here since 1977. Taint no such Special Training Regiment here.

>>>He said the tank is "compartmentalized." "If a round by chance penetrates, you have compartments that protect other crew members."<<<

There is a Driver's compartment, a turret and an engine compartment. There are no compartments as this guy represents. There are some very potent RPGs around and have been for years.

[steplock]

"in your view should the media only report positive stories about everything"

Nope - I abhor the excuse of "news" to lay out classified information to make sure the enemy can kill even MORE AMERICANS the next shot.

Why in the hell should you expect the military to tell YOU exactly how a person was killed inside a very well built tank?

Do you want to kill American tankers? If you read that "If you shoot the RPG-7 from 130 yards at a 88 degree angle into the right-rear-quarter panel direclty behind the #3 plate, there will be a 99% chance that a piece of shrapnel will enter the tank", would that placate you?

satisfied?

[inflation]

not once did i say that the media should provide such info, if you think i did then show me, otherwise stop putting words in my mouth.

[Jeff Head]

Don't be rediculous Poohbah...it's a function of the propellant. We fire such weapons off of aircraft and the length is nothing like a MBT gun...the secret is the design of the penetrator and the propellant.

But, as I said, the much more likely scenario for something that is more modern than an PG-7 is the Kornet. Outside of that...perhaps the RPG-7 made a good hit, particularly if the shot came down from above.

[Robert A Cook PE]

Only part of the M1A1 armor is depleted Uranium. Most is a classified series of "thin", high strength steel/Kevlar plates angled to "splash" the high energy gasses from a shaped charged around and deflect them. Theoretically, a single shaped charge of gas could get through between the plates if it hit at just the right angle to go between the angled plates and hit the inside steel with getting deflected.

For example, maybe the RPG came form above and hit the turret at an angle that a "regular" round from a conventional tank on the ground couldn't get to.

Or, the round could have hit the joint between the turret and main body. It could have hit the hatch itself (which is just "regular armnor plate"), and the driver/gunner (?) be inside just below the hatch. taht would injure/kill the driver, even if the hatch were shut.

[Poohbah]

Don't be rediculous Poohbah...it's a function of the propellant. We fire such weapons off of aircraft and the length is nothing like a MBT gun...the secret is the design of the penetrator and the propellant.

The gun you are referring to is pretty big.

...the secret is the design of the penetrator and the propellant.

Sir Isaac is NOT mocked, despite your fervent wishes. Anything with enough foot-poundage to reliably punch through that much Chobham armor and inflict significant damage to the interior of the vehicle, using only kinetic energy, is going to have one hellacious recoil. The only way to damp said recoil to tolerable levels is to have some sort of recoil mechanism, which in turn drives up the total mass of the weapons system.

But, as I said, the much more likely scenario for something that is more modern than an PG-7 is the Kornet. Outside of that...perhaps the RPG-7 made a good hit, particularly if the shot came down from above.

Kornet is unlikely. Kindly look at your typical city block. Getting 100m of unobstructed LOS is rather difficult, particularly if you are trying to fire from a position of concealment.

My guess: an RPG-7 shooter got extremely lucky.

[Robert A Cook PE]

The writer is probably using this quote (which isn't exactly right anyway) to refer to the amored storage compartments in the aft turret - which ARE designed to let the rounds explode, but "vent" the explosive forces outside (providing the access covers are shut!) so the crew can survive.

[Robert A Cook PE]

Nah.

The reactive armor is a poor second place design intended to "mimic" the Chobham armor on earlier tanks that can't apply the real stuff.

Look at the true tank-tank fights in Gulf War I & II to see the resutls: the chobham armor is the best out there.

But it isn't perfect against every weapon form evry angle. It can't be.

We've now lost TWO tankers since 1992 that got only two weapons through the armor - both to hand-held weapons at close range in city-type environments. That ain't bad.

The M1 wasn't intended for "police" patrols inside cities where somebody can basically walk up to the tank with a mine or RPG at 3 paces and fire!

[Jeff Head]

You are presuming I mean the DU 30mm round...you are presuming wrong.

Hyperveocity can also be achieved through the use of rocket propellant...and we have them, along with the kinetic penetrator warhead at the sword end.

Depending on the location of the tank, and whether it was sitting or moving...you can certinly obtain 100m LOS. ie. park one at an intersection.

As I said...most likely a Kornet, or a lucky RPG-7, perhaps with the newer shoot from above warhead.

[Jeff Head]

The M1 wasn't intended for "police" patrols inside cities where somebody can basically walk up to the tank with a mine or RPG at 3 paces and fire!

Amen.