What is that stuff hanging down off the bottom of the rear of the turret?  It looks like metal ball fringe.  Is it part of the armor?  

If you are talking about the Merkevas...I think that they hang chains off the back to block off the shot trap that exists there.  they will set off any rockets that might otherwise take the turret off.

I never understood that part of the design..... always looked like a weakness.

I haven't seen it myself, but from what you describe I would guess that it might be some sort of metal chain screen? If that's what it resembles I'd guess that it might be used to prematurely detonate HE rounds, protecting the lesser-armored turret-rotation collar region?

My .02

I saw that too. My guess was that it protects a critical area from direct RPG impact. I dont know Jack about a tank but assume that the area that joins the turret to the body is a weak link. I'm sure there are some tank jockeys here to answer our questions though.

[img]http://ca.yimg.com/i/cf/reuters/20010829/i/3959947277.jpg[/img]

[img]http://info.jpost.com/2000/Supplements/Lebanon/PhotoAlbum/1.jpg[/img]

I couldn't find any pics with the fuzzy dice or chrome rims :)

If all the above informed comments are correct – it would indicate where the terrorists should fire their second round.

BTW, what are those guys doing? Are they offering to dust-off the tank?

Stcyr: They are a camera crew, thats the microphone on the pole, the closest guy on the ground is holding the video camera.

Kharn

I wonder if they have a chrome chain steering wheel.

Those comments are correct, but stcyr you are assuming that the terrorists will get a second shot![img]http://boards.straightdope.com/sdmb/images/smilies/happyyid.gif[/img]

So how do the Abram M1A1s handle this? Or the Leopards?

I always thought those chains resembled the tassles on a Jewish prayer shawl!

How appropriate!

Eric The([i][b]MeneMeneTekelUpharsin[/b][/i])Hun[>]:)]

ETH.....they are designed NOT to have shot traps like this.  Thats why I wonder what the designers were thinking on the Merkeva...

Here is a Leopard rear shot.

[img]http://w1.500.telia.com/~u50015076/122_frr_fageltorn_soder.jpg[/img]

Here is the Abrams

[img]http://www.army-technology.com/projects/abrams/images/abram1.jpg[/img]


Here is a great shot of the chains.....notice the large area a RPG could enter....

[img]http://www.voodoo.cz/merkava/images/mk3/mk3_9.jpg[/img]


This gives you an idea as to just how bad the MK1 Merkeva started

[img]http://www.voodoo.cz/merkava/images/mk1/mk1_12.jpg[/img]

The chains were designed as a response to a possible well place RPG shot on the Merkeva turret ring. The chain would intereve with the fusing system on the RPG causing it to explode premature.

Eric,

Liked the prayer shawl analogy – only as an afterthought. But wouldn't you think that if you were deseigning an Israeli tank you would have their specific enemy in mind and the type of weapons they were likely to encounter?

Don't get worked-up, this is not an attack on Israel, just a comment on their tank deseign.

BTW, if those guys weren't offering to dust-off the tank, why do they appear to be haggling over the price?

As noted by all the ball and chain is to protect against RPGs primarily.  The reason for the upward angle of the turret bottom at the rear is so the driver's head isn't chopped off by the turret bussle when it's traversing.  Notice the picture of the Merkava with the camera crew.  The driver's hatch is just in front of the turret on the left of the vehicle (closest to the camera crew).  The curtain of chain just starts far enough forward to miss him, the turret starts angling up right from the turret ring so that misses him as well.  Driver's postion was dictated by other requirements, so the fix was to angle the armor.  Not really a good fix, as shot traps are a problem with any tank design.  The fix for the fix was the chain with wieghts.  

Ross

yeah, but now won't the driver get smacked in the head by steel balls?

They could have just used the fix that the M1 designers did. Driver drives buttoned up unless turret is locked.

One thing guys.. alot of the posts here seem to greatly overestimate the quality of the anti-tank devices employed by Israel's enemies (much less the PLO) and the training of the soldiers they face. As cartman put it, "they're sand monkeys!"

Tanks move rather fast and RPGS are not very accurate! The ones the Palestinians (and most of the Arab armies that Israel borders) have are not effective anti-tank weapons. The Merkava is one of the most survivable tanks in the world, to the point of sacrificing other normally very desirable traits such as speed. The design of the Merkava was a direct result of Israel's battlefield experience which includes a few of the most notable armor battles of the 20th century. Comparing this to the way many other tanks are designed, I think I'd trust the designers knew a little more about what they were doin ;)

No, the driver won't get smacked in the head by the steel balls, as they start hanging down far enough to the rear of the turret that his head will be clear of the dingle balls.  

As far as staying buttoned up, the Israelis don't.  That's just them.  They don't stay buttoned up in M113s or anything else either unless it makes more sense to do that.  They didn't go with the "buttoned up" requirement because they chose not to.  That's just the way they operate.

Ross

While it did incorporate many lessons learned from tank battles, like having a huge ammo capacity and great survivability, they obviously wouldn't have just added the steel chains unless they had a reason.  

I wouldn't call the design defective.  I would call the chains simply an upgrade for a viable threat.  In Lebanon, the Merkava delt with Syrian T-72s easily, but in the city streets, RPG armed troops did present a danger.  Calling them "sand monkeys" and ignoring the threat they pose because of arrogance is not in keeping with a country that has combat experience and cares about it's troops lives.  They take the neccesary steps to protect their troops.  Adding the chains was one of those steps.  

Ross

I think you are over-looking a couple of things...

1) The chains are shiny. This serves many purposes such as being a distraction in combat for the "sand monkeys" as well as being easier on the eyes in that you don't see that main battle tank parked on your street, you see those bright shiny chain dealies...and you start to wish you had some shiny chains. This distracts the average palestinian but not the israeli grunt, they are trained to phase out the chains thereby gaining an advantage in combat...also the chain-ball thingys are standard issue...so the israeli soldiers don't steal them from the tanks.

2) Chains make jingle noises. This is to Israel's advantage for many of the same reasons as in #1

3) Clearly the Israelis are trying to "win the hearts and minds" of the world with their mystical shiny things and magical noise making dealies. I for one have been bought.

4) The chains can double as snow-treads if the need should arise.

5) If the Israeli army has a shortage of ammo the chain-ball things can be attached to sticks to form deadly maces.

6) All of these things are probable, that and the whole RPG thing

Unlike the M1 Abrams and the Leopard II doesn't the MK1 Merkeva have the engine in the front?

Yes the Merkava has a frontal engine.

This freed up the rear of the tank to allow for HUGE ammo reserves or a small squad of infantry to be carried in the rear.

It is an otherwise great design if you take away the shot trap.. Mind you as it has been pointed out it was not designed for urban conflict.

Shape charges such as the ones found on the H.E.A.T.type of anti armor weapons work on the explosivly formed projectile principal. This projectile consists of a cone of deformable metal (copper) that is compressed by the explosive. This compressed liner travels at around 6,000 fps. and has a relatively small frontal cross section. The method of armor penetration is one of extremely localized pressure combined with heat, The effect is greatest when the nose of the warhead detonates against the target. The reason for this is the penetrator becomes unstable when traveling through air. The farther it travels through the air the less stable it is, the less stable it is the less armor it will penetrate. (hence the dingle berries on the turret)

H.E.A.T. warhead armor penetration is predicated on warhead diameter for instance the RPG 7 warhead will penetrate around 12 inches of rolled homogeneous steel (armor plate) this makes this little weapon quite handy if you're a grunt. Contrary to popular belief TOW, Millan, HOT, Hellfire, RPG, LAW ect. do not "blow the turret" off of anything but they do introduce a plasma (hot as crap) jet into the interior of an armored vehicle. It is the hope of the dude firing the weapon that this plasma jet or any of its spall (cone of molten crap) lands on or goes through things that go boom (Ammo, Fuel, Clothes, People ect.) when this happens then the turret might fly off but by then it is a moot point. It is important that when one discusses these or other weapons they aren't lulled into false assumptions due to the fact that you might one day be facing these same type types of goodies sould the crap really hit the fan.

As a side line one of the best field expedient defenses against H.E.A.T. type weapons when in a stationary position was and still is chain link fence.