I have a question about the protective benefits of cover with regard to heavy
weapons (tank guns, missiles, etc.).
How effective is natural and man-made cover in protecting a vehicle from
anti-armour fire?
Take, for example, a tank that is hull down in a man-made tank berm. If
a
modern anti-tank weapon (say a 120mm anti-tank gun, your choice of best
suited ammunition) were to hit the berm instead of the tank, is it completely
defeated from hitting the tank? Or is it defeated enough that it won't
penetrate the armour even if it gets through?
What about a tank hull down on a hill? Any idea of how much "hill" could be
penetrated before the round would be useless at penetrating the armour?
I'm working on extended vehicle rules for SG2, and I was thinking of armour
values for things like ridgelines and berms. Obviously the thickness of these
things is important to their effect on anti-armour weapons. However, I
don't know how much earth or ground would be needed to totally protect a tank.
What I was thinking of doing was giving vehicles additional armour dice based
on whatever they were using for cover. A vehicle on the edge of some woods,
for instance, would probably get to add an additional D6 armour (this is using
Jon's new system for armour impact where instead of rolling 1 die x
weapon/armour class, a number of dice equal to the weapon/armour class
are rolled and totalled). I was trying to figure out how protected a tank is
when
it's hull down behind a hill or a man-made tank emplacement. I have a
rule in mind for handling hull down tanks if these emplacements are 100%
effective, but if they aren't, I need to come up with some armour die value to
represent a weapon that penetrates the berm and then strikes the tank.
Any help would be appreciated.
> --- Allan Goodall <agoodall@att.net> wrote:
> Take, for example, a tank that is hull down in a
Depends on the type of soil, angle of attack, and depth of berm.
It was pretty conclusively demonstrated in Desert Storm that bulldozed berms
of sand are pretty useless. But a proper tank fighting position is something
else entirely.
On Wed, 28 Aug 2002 12:54:54 -0700 (PDT), John Atkinson
> <johnmatkinson@yahoo.com> wrote:
> But a proper tank fighting position is something else
Would a proper position (made from packed earth, I take it?) be mostly
impervious to anti-tank fire or completely impervious?
Sand is completely useless? Not surprising, but quite interesting. I'll take
that into account.
IIRC the account as listed by Tom Clancy was that an American M1 spotted
an Iraqi T-72 moving behind a sand berm. The berm was 15 feet tall so
direct sight of the tank was lost. Using the thermal sight, the heated exhaust
plume of the Iraqi tank was visible rising above the berm. Calculating where
the bulk of the tank should lie, the M1 fired through the berm. The APFSDS
went through the berm and through the Iraqi tank. I don't think that the range
was listed. From pictures I've seen of the
sand berms, they were 20-30 feet thick.
--Binhan
> -----Original Message-----
Excerpted from "Victory Misunderstood: What the Gulf War Tells Us About the
Future of Conflict" By Stephen Biddle
> From International Security, Vol. 21, No. 2 (Fall 1996)
First, Iraqi defensive positions were very poorly prepared. The "Saddam line"
at the Saudi border was haphazard at best (although given the poor quality of
its conscript garrison, it is unclear how significant this was). More
important for the outcome, the Republican Guard blocking positions were no
better Western armies dig their fighting positions into the earth below grade,
and hide the soil removed in excavation. The Guard, on the other hand, simply
piled sand into loose berms, or mounds, on the surface of the ground around
combat vehicles and infantry positions.(64) This gave away the defenders'
locations from literally thousands of meters away, as the berms were the only
distinctive feature of an otherwise flat landscape, without providing any real
protection against the fire this inevitably drew.(65) Loose piles of sand
cannot
stop modern high-velocity tank rounds. In fact, they barely slow them
down. U.S. crews in 73 Pasting reported seeing 120 mm tank rounds pass th!
rough Iraqi berms, through the Iraqi armored vehicle behind the berm, and off
into the distance.(66) No U.S. tank crew would leave itself so exposed.
--Binhan
> -----Original Message-----
> At 3:05 PM -0500 8/28/02, Allan Goodall wrote:
I'd expect that a large layer of sand would be great for absorbing the energy.
A berm pushed up around the tank will be good for nothing. a few feet being
the useless amount. 10 meters of sand...really good.
> At 12:54 PM -0700 8/28/02, John Atkinson wrote:
Boy does it. Its just like armor.
> It was pretty conclusively demonstrated in Desert
You have to have a pretty thick amount of soil to stop what ever is coming in.
With KE weapons its really a ballistic penetration issue. If you have a
relatively thin wall or berm, the long rod penetrator coming in might just
shrug at the layer just like a.308 round will shrug at a police man's level
IIa vest. But if you put a good thick (several meters) berm in front of the
layer of armor on the tank, the projectile may loose enough energy to go all
the way through the berm but not carry enough E to penetrate the armor of the
vehicle hiding there. Its really not a yes or no question, but rather a how
much.
A solid bit of ground with rocky bits to it will likely work far better than
light sandy spoil if pushed up into a protective bank. But it had better be
thick enough to stop what's coming in. John, are
there specific guidelines on what thickness of a given material/spoil
will stop an incoming 125mm APDS round?
ie like
X meters of concrete X meters of rocky soil X meters of sandy soil x meters of
wooden crib with rocks and dirt filling it.
I would expect that in order to make a good proper Tank position you have to
have a scrape in the ground that gives you a really long distance of ground. A
berm pushed up around a tank isn't going to do much good. It has to be dug in.
I have to wonder with the advent of top attack weapons, whether we'll start
seeing more over head cover made for tank fighting positions or not. Dig a
scrape for a tank with the two levels and then lay some beams and logs over
the top. Then drop spoil over the top of the beams to protect the top of the
tank. IT'd have to roll out to get the turret down position. Its additional
supplies and work, but if it protects your mobile forces, it'll be worth it.
<----enemy __---dirt_--__
-------- - - - - - - - - - - XXXXXXXXXXXXXX
\_hulldown__ /
\_turret down____ covered /
\_____area___/
> At 2:13 PM -0600 8/28/02, B Lin wrote:
At the base or at the point where the round penetrated. Given how sand doesn't
like to slope very much when dry, I'd expet that the berm had to be far
thinner at the top than at the base.
> --- Allan Goodall <agoodall@att.net> wrote:
Depends on where it hit. A tank fighting position is a hole dug in the ground,
not dirt piled up on top. So most shots would either fly over the tank or slam
into the ground and have a significant amount of dirt to travel through. I've
got to go to work in a couple hours, but tomorrow I'll post the data from the
Survivability manual.
> --- Ryan M Gill <rmgill@mindspring.com> wrote:
> coming in. John, are
FM 5-103, P 4-13
"If the expected enemy uses kinetic energy direct fire projectiles or
hypervelocity projectiles, it is impossible to construct parapets thick enough
for protection. To protect against these projectiles,
deep-cut, hull defilade, or turret defilade positions
are prepared."
> FM 5-103, P 4-13
That's garbage. Build a parapet with a top of a minimum 10 feet. Compact the
material. Then pound 1" or larger diameter rebar into the front of the top of
the parapet every 2". Any incoming APFSDS that goes all the way through the
parapet will hit the rebar. That will both slightly horizontally deflect and
massively deform the incoming round. The round will then loose most of its
energy travelling through the rest of the parapet.
This is an extrapolation of a very nifty technique the Swede's used to
up-armor (for wartime use only, it was secrets for many years) the
S-103b.
They had steel bars that would fit into very the front of the S-103b.
Is it any wonder that Sweden was the first country to deploy the top attack
anti-tank missile?
Oo, I love it when we get credit for something.:) They were just a single row
of steel rods designed to work like the chains hanging from the Merkavas
turret. (At least the ones I've seen, there might have been other variants) We
also used jerry cans filled with diesel fuel on racks all over the sides...
(for HEAT round dispersion) My officers told me it would work since diesel
ignites badly, but I still sceptical since a HEAT round, like the name
implies, is very
hot. :)
Probably does though. I thought I knew stuff before I joined this grup, but
I'm getting more convinced of the opposite by every day...:)
> This is an extrapolation of a very nifty technique
> "Johan Böjeryd" wrote:
The jerry cans would have worked as advertised, in just the same way as the
Merkava chains or the screens of chicken wire put on some vehicles or
fortifications. Some tanks use the space in their spaced armour as fuel tanks
(Merkava again, so I've read). According to what I've read on
sci.military.moderated this chain
of thought (spaced armour good, spaced-armour-with-fuel better)
leads to the composite armours in use today.
I'm sceptical about pushing earth up around a tank, whatever it's reinforced
with. Once you've pushed that much earth around you might as well have scooped
out a big hole and put the tank in it.
> Probably does though. I thought I knew stuff before I
That *is* one of the risks of hanging out with this crew. You idly speculate
about something completely out unrelated to what this list is theoretically
about, and you discover someone on the list is an expert.
The corollary is that when you heatedly assert that thus-and-such is the
case, you often find the person you're disagreeing with has a PhD and 26 years
professional experience on exactly that topic...
> --- David Brewer <davidbrewer@blueyonder.co.uk> wrote:
> I'm sceptical about pushing earth up around a tank,
Which is why AFV fighting positions are usually scooped out big holes with the
tanks in them.
> --- "Imre A. Szabo" <ias@sprintmail.com> wrote:
Do you have any earthly idea how long that would take??
I mean, have you ever operated US Army earth-moving
vehicles? I've been an ACE crewman and I can assure you that with the
resources of an Armored division and even a week's time, there is no way in
hell you could construct enough of those things to shelter even a batallion's
worth of armor.
No, the way to create fighting positions for armor is digging holes, not
creating parapets.
> Imre Szabo wrote:
> That's garbage. Build a parapet with a top of a minimum 10 feet.
Compact
> the material. Then pound 1" or larger diameter rebar into the front of
Is it
> any wonder that Sweden was the first country to deploy the top attack
Um... Imre? This extra armour was against *HEAT* rounds. Not against KE;
definitely not against APFSDS. In addition this "armour" had a tendency to
send a large shower of splinters straight into the tank's sights when hit by
pretty much anything larger than a side arm, thereby considerably
faciliating an F-kill by weapons which otherwise would've been too light
to threaten the tank seriously from the front...
Now, your parapet design might work... too bad that you'll only be able to
build one such parapet-equipped fighting position per tank company :-/
Regards,
I wouldn't care for the chances of any infantry anywhere near a tank that
absorbs a heat round into a jerrycan of diesel. I'm not sure if the
fuel would splash, but even if it doesn't you'll get something like a splash
efefct from the explosion of the warhead. And that means droplets
of fuel, which is what you need to get it to ignite. Burning diesel everywhere
and probably one heckuva fireball. If it really needs to be atomized to
ignite, then you might get a splash before it ignites.
The tank shouldn't mind much if it's buttoned up, but I hope modern armor is a
good insulator.
Any comments from wiser heads, or just hysterical laughter?
> David Brewer wrote:
> "Johan Böjeryd" wrote:
> Do you have any earthly idea how long that would
You did not specify a time requirement. If you're the Iraqi's and you've got
the U.S. threatening to invade, you've got plenty of time while the
U.S.
builds up to invade.
> I mean, have you ever operated US Army earth-moving
Never been an ACE crewman. I have had entirely too many brunettes to
chase...
Most fortifications take time to build. Look at Verdun, Metz, etc. You plan
these thing in advance. Modern example, South Korea.
> No, the way to create fighting positions for armor is
Assuming the terrain you are in allows you the luxury of digging down instead
of building up. There are a lot of place in the world where digging down won't
work. Examples, most river delta's (including the one in Iraq), half of
Florida, about a third of the Leningrad Oblast, the Pripet Marshes, etc, etc,
etc.
> Um... Imre? This extra armour was against *HEAT* rounds. Not against
That's interesting, the article I read specified APFSDS, not HEAT. It did not
specifiy what happend to the bars. While I'm not surprised that the bars
shattered, the article did specify that 120mm APFSDS was not capable of
penetrating the front of the S-103b. While the fragments aren't good,
I'd
rather deal with them then that un-disrupted APFSDS. As for the sight,
either shutter them, or periscope them.
> Now, your parapet design might work... too bad that you'll only be
Only if you don't build them in advance...
> --- "Imre A. Szabo" <ias@sprintmail.com> wrote:
Sure.
They tried that. You know what happened? You were paying attention when the US
drove two corps around their right flank, right?
> Most fortifications take time to build. Look at
You're assuming that your enemy is stupid enough to
attack them head-on. Not a good plan unless your
terrain is as restricted as South Korea. And even then, such prior planning
allows your enemy to get beautiful satellite imagery pinpointing down to a 10
digit grid exactally where each one of your spiffy tanker graves are located.
You loose, when attack aviation or artillery paste
every one of your tanker graves at H-Hour.
> > No, the way to create fighting positions for armor
When was the last time someone drove tanks into marshes in the first place,
much less planned a deliberate defense around armored formations in
marshlands?
Some support to the idea that you don't want berms:
http://www.comw.org/rma/fulltext/victory.html
In which an analysis of 73 Easting is performed and Biddle points out several
problems with the Iraqi berms.
First, the location of the berms gave away the location of the vehicles. Being
the only terrain feature on an otherwise flat area makes it very easy to
pinpoint possible targets. US procedure is to put the vehicles in defilade
(hull down or turret down) and remove the spoil. When in a turret down
position, there is nothing for the enemy to target on and it is much harder of
them to estimate your position.
He also states that it was standard procedure to fire at any berm, regardless
of whether an Iraqi vehicle had been spotted or not.
Second, the berms were highly visible in a strategic sense, it was easy to
spot where the Iraqis had built up and therefore easier to plot
routes that avoided strong-points (although that turned out to be
unneccessary) A tank in a turret down position can be covered with camoflauge
to make it more difficult to spot, or defilade positions can be covered to
simlulate an occupied position. It's harder to hide a tank sitting behind a
berm.
Third, the material of the berms (loose packed sand) did not prove to be a
significant barrier to American shot. (Whether this is DU or not is not
listed).
Fourth, (my comment) a tank in a proper Turret-down/Hull-down position
can move from full cover, to partial cover to withdrawl, whereas a tank using
a berm is either full cover (not shooting) or shooting (no cover).
--Binhan
[quoted original message omitted]
[quoted original message omitted]
> Sure.
Back then the Iraqi's didn't have GPS so couldn't navigate in the deep desert.
That is no longer true. Besides, last I heard, neither Kuwait nor Saudi Arabia
are interested in letting U.S. forces on their soil in the next go around...
> You're assuming that your enemy is stupid enough to
Only if the tanks are really there when arty and air show up. Decoys in
fixed forts are a great way to set-up anti-aircraft kill zones...
Besides, gravel bombs make satelite recon useless for determining which
positions have tanks in them in real time, which means you are stuck shooting
at
positions that might have a tank, or might be an anti-aircraft kill
zone...
> When was the last time someone drove tanks into
The Germans and Soviets drove tanks all over the Leningrad Oblast (ok, the
Germans didn't because they never took Leningrad). The Soviets specifically
designed tanks with low ground pressure to be able to operate them in Russia
year round. Why? Because for a couple of months a year, most of Russia is a
marsh.
Besides, DS and SG have both grav vehicles and hover vehciles, so you have do
have the abilty to fight in marshes.
At risk of displaying ignorance: Does Iraqi use of GPS require access to the
U.S. satellite network? If so, can the U.S. block their use without disrupting
their own?
[quoted original message omitted]
Short answer - yes. Long answer - sort of. The US military can add
"noise" to the GPS signal making it less accurate - i.e. position within
100 meters or within 1 km rather than within 3m. With that kind of error,
using GPS to plot artillery or bombing missions is much more difficult.
Military units can use a corrected signal or supplement with ground based
signals to remain at the 3m accuracy of GPS.
--Binhan
> -----Original Message-----
> B Lin wrote:
GPS has two signals -- an open "civilian" channel and an encrypted
"military" channel.
Noise can be added to just one channel -- the civilian one, of course.
They've also figured out how to add noise to only certain regions. I don't
know how large a region it has to be, but, for example, they could
mess up the civilian channel in the Middle East, but leave it untouched in the
US.
In the GZG universe, I think the first thing you do when you have space
superiority is to replace -- or take over -- the local GPS
constellation. And, GPS can be used to determine your location in space near
the planet.
> > Um... Imre? This extra armour was against *HEAT* rounds. Not against
Put it like this: *Old* 125mm WarPac APFSDS (fired from a T-72 in the
tests) were well capable of penetrating the front of the S-103b with the
"grill armour". When tested, the rounds penetrated into the S-tank's
autoloader... which is pretty much as far back as you can get in that tank.
Even the older Western 120mm APFSDS had better penetration than the old WarPac
125mm rounds, mainly due to their better L:D ratios. (The length of the WarPac
rounds were restricted by the size of the autoloader.)
So... if this article a) says that the "grill" was designed to stop APFSDS
and b) made the S-103b impenetrable to even an early 120mm APFSDS round,
then I wouldn't believe anything else it says either if I were you.
Regards,
> --- "Imre A. Szabo" <ias@sprintmail.com> wrote:
I doubt the Iraqis have enough GPS to matter. And even if they did, they
havn't got the logistical structures to run around the deep desert. If they
did have the logistical structures, the USAF would go
buck-wild clusterbombing fuel truck convoys. The
beautiful thing about the deep desert is that it's too flat for any meaningful
radar shadow, so things like JSTARS work real well.
Besides, last I
> heard, neither Kuwait nor
Last I heard, neither Kuwait nor SA are stupid enough to argue with us should
we choose to ignore their wishes.
Or we can use Turkey as a jumpoff point. That gives us friendly locals work
with.
> > You loose, when attack aviation or artillery paste
That presumes you've got the AA assets to do something that good. I doubt Iraq
does. And I'm sure the USAF plans for these things. Do you know how many air
defense supression missions were flown in 1991?
> gravel bombs make satelite recon useless for
You have to have launch assets, which the Iraqis don't.
> Besides, DS and SG have both grav vehicles and hover
Neither of which are going to be sheltering behind berms because of the
maneuverability of grav
vehicles--I'll go right around your prepared defenses.