Destroying a Tank in less than a dozen shots

[apoc527]

Quite simply--how do you do it?  The main battle tank has a +35 damage save and is Huge, giving it (I believe) 6 damage saves until broken and 12 until destroyed.  Let's take two enemy tanks, each armed with APDS rounds for their 120mm cannons.  Those do like 7d6 (AP 60).  But they aren't explosive damage...so, even though the tank's Damage save is reduced to -25 (I'm assuming it can go negative), it seems like an APDS round can only ever cause "1 failed damage save," except on a crit, of course. 

Given that APDS rounds are really effective, should it really take almost 12 shots to destroy an enemy tank? 

[Krensky]

Well, considering the M1A1's (the archetypal modern main battle tank, and what the generic in the book resembles) armor is equivalent to 940-960 mm of rolled homogeneous armor and the M829A3 APFSDS round has a penetration of between 680 and 790 mm of rolled homogeneous armor (depending on angle) I'd say yes. Especially because M1A1s have survived multiple hits from other M1A1's cannon firing APFSDS in both friendly fire and abandon and destroy situations. Also, note that while it would take twelve hits to destroy the MBT, it would only take six to break it, which is just as good.

However, if you think twelve hits is a bit much you could just rule that APDS, while not BLS, receives the multiple save failure benefit of BLS. This would, on average, resulting in it only taking four hits to destroy a MBT, and only 2 to break it.

(click to show/hide)

Average damage of 24.5
12 + 10 = DC 22
-25 to roll = average adjusted roll of -14.5
22 + 14.5 = 36.5 = 3 failed saves

[MugMug]

As an aside, while doing some research at work I came across some fascinating (and official) anecdotes about the effectiveness of DU rounds and the turret armor used by the Abrams. I'll have to see if I can dig those up again and, if unclassified with no caveats, share them.

Walter

[TheTSKoala]

Depleted Uranium.  Impact creates an exothermic reaction against a target effectively melting a hole into the armor through a transition of heat and oxidizing chemistry (if memory serves me right).  Once beyond the armor, the round continues the exothermic reaction which creates a cloud of super heated I want to say Titanium / Lead / Uranium.  The cloud is then able to cause significant burns to any soft target in the area or, in some reports, ignite and / or detonate fuel stores or artillery shells.

If I'm off target, let me know, but I'm pretty sure that's how they work.  ...I still prefer Thermobarics.  A lot less chance of the user coming home with 3 eyes, 7 fingers and 14 toes.  Plus cancer. 

As armor, not a clue.  Never a tank jockey. 

[apoc527]

I like Krensky's solution.  As a matter of fact, I think I might make the additional saves failed per 10 by which the damage save failed a standard feature of all weapons or damage types and then simply have BLS weapons fail an additional save for every 5 (maybe 7) over.  That should give me some more BOOM for my buck.  Thanks!

[Krensky]

That will make everything way more fragile and explosives way cheaper then they should be for their effectiveness.

[Sletchman]

According to an Armoured Calvary mate of mine the rules and stats for tanks are "reasonably accurate" - just don't forget location damage.  As he put it "Hit my tank in a certain spot even once and its rooted".

[Mister Andersen]

I though the point to DU was that it was simply very dense so did disgusting amounts of good old kinetic damage

[Krensky]

DU staballoys are the favored material for long rod penetrators for few reasons:

• Very high density
• High hardness
• Self-sharpening, meaning that as the penetrator fractures and breaks down it does so in a way that the tip of the rod remains pointed
• Lower material cost then equivalent tungsten alloys
• Lower manufacturing cost then equivalent tungsten alloys
• Domestic supply, most tungsten reserves in the world are in China and the US has none worth mentioning
• Less carcinogenic the equivalent tungsten alloys
• DU dust is pyrophoric, meaning it will spontaneously ignite at room temperatures, making a DU APFSDS round incendiary as well as armor piercing

Please note that the M829A3 round I referenced is a DU penetrator. Another alternative is to add simple say that APDS rounds can have API added to them, and then make called shots at the fuel.

Late model M1A1s along with M1A2 and M1A2SEP MBTs also incorporate DU into their front armor because of it's density and hardness. It's important to remember that a modern MBT's only relation to a WWII or Vietnam era battle tank is that they're both tanks. It's like comparing a iron-clad screw sloop with a dreadnought-type battleship. A current generation MBT takes a lot of killing or a good amount of luck. Most, not all, but most M1s damaged from enemy fire were still effective, or were repairable effective kills (meaning the tank is intact and repairable, but not working at the moment, exactly what the broken condition represents).

[TheTSKoala]

I though the point to DU was that it was simply very dense so did disgusting amounts of good old kinetic damage

I believe that's also why they use it in Tank armor.  (Any tank jockeys to back up my theory on that one?)  But yes, as Krensky, god of all things obscure, pointed out the Depleted Dust almost works like White Phos.  Creates a thermal-energetic cloud that burns quite well.

[MilitiaJim]

(Any tank jockeys to back up my theory on that one?)

I can ask my ex-tanker buddy, but yeah, the DU in the armor is there to keep things out.  There is ceramic in the mix to defeat HEAT rounds too, it's a crazy layered mix of awesome.

The other thing to keep in mind is that the M1 is the best tank on the planet.  Nothing else matches its tactical mobility and firepower.  And the things can sneak up on you in the woods.  Disturbing but true, by the time you hear it, it is almost certainly too late to effectively hide.  The noise of Bradleys and HMMWVs carries much farther.

The tanks PCs will usually face are much less bad ass.  (And have inferior crews too.)  Even molotov cocktails can do nasty things to the T-54/55s that dictators use to oppress the people.

[MugMug]

I found one of the sites about which I was talking. This is an environmental exposure report about DU use in Gulf War 1, found here: http://www.gulflink.osd.mil/du_ii/.

The unit (part of the 24th Infantry Division) had gone on, leaving this tank [mired in the mud] to wait for a recovery vehicle. Three T-72's appeared and attacked. The first fired from under 1,000 meters, scoring a hit with a shaped-charge (high explosive) round on the M1A1's frontal armor. The hit did no damage. The M1A1 fired a 120mm armor-piercing round that penetrated the T-72 turret, causing an explosion that blew the turret into the air. The second T-72 fired another shaped-charge round, hit the frontal armor, and did no damage. This T-72 turned to run, and took a 120mm round in the engine compartment and blew the engine into the air. The last T-72 fired a solid shot (sabot) round from 400 meters. This left a groove in the M1A1's frontal armor and bounced off. The T-72 then backed up behind a sand berm and was completely concealed from view. The M1A1 depressed its gun and put a sabot round through the berm, into the T-72, causing an explosion.

Good times.

Walter

[EDIT: It's worth noting that one-shot kills are a big deal.]

[MilitiaJim]

I can practically hear that Abrams going from "oh s***!" to "NOM NOM NOM."

[TheTSKoala]

I can practically hear that Abrams going from "oh s***!" to "NOM NOM NOM."

I'm not sure what's worse... the face of sheer terror the T-72 crew must have had after the first one blew up... or the fact that www.icanhascheezburger.com was just quoted for a victorious MBT battle.

[apoc527]

Alrighty, I'm convinced.  I'll just call APDS rounds special and treat them as explosive for up to 2 bonus failed saves (total of 3).  That seems a fair compromise to me.