Weight and size of Main Battle Tanks

[Durandal]

I keep hearing how MBT's are basically at the upper limit of how big and how heavy they can be build.
At least it's said that you can never build a tank heavy enough with conventional armor to defeat modern anti tank threats.
I've heard that there wouldn't be a road able to support such a tank. but i never knew tanks were supposed to use roads to begin with.
Anyway i'm curious as to why tanks can't simply grow to battleship size?
Certainly having more armor would eventually make it unfeasible to use shoulder launched anti-tank missiles due to the shear weight of the explosive charge required to breach the armor.

But basically my question is, why can't they build such tanks? As i don't think it's a technological problem, there is something else , i also don't believe it's to do with being unable to use roads since tanks were never intended to use them in the first place.
A tank simply goes over and through things

Anyone have any thoughts on this? Thanks.

 

[Wahuuga]

sheer physics. the heavier you go, the larger you become, therefore easier to target. Also, the heavier you are, the larger power plant, therefore more fuel needed. therefore larger supply trains etc.

Also, modern battlefields require rapid deployments, so you need to be light enough to be moved around by ship, I don't really know what they use but i'm sure if your too heavy then only the largest ships can move you. Which means you require a post, and that isn't always available.

Also, i think the future of armor is in reactive/preventative armor, not just thicker steel. Lighter, faster vehicles are harder to hit, and modern composite armor's are not all together that heavy.

Also, a extremely heavy vehicle would have excessive wear on drive trains, etc.

So pretty much, all the negative things about heavy tanks get amplified as they get bigger, you need to think practicly about these things.

 

[Feanor]

It's a trade-off. And by the way armor thickness isn't directly related to size. You can have smaller tanks that are better armored.

 

[Waylander]

There are several reasons.

1. As said before there are technical problems like the engine, drive train, etc.
2. The bigger you get the more space needs to be protected.
3. Roads are important as they are used to for relatively fast deployments within an area of operations. Driving cross-country is much slower and costs more fuel.
3. The mentioned transport by ship is the smallest problem. But the needed ability to transport a tank by train or flatbed truck is utterly important.
4. Bridges are another problem. Crossing a River becomes difficult when you are too heavy for most bridges including your own bridgelaying equipment.
5. The bigger you get the harder it is to conceal you.
6. Due to costs and logistics an army could operate only smaller numbers.

BTW, several modern MBTs are very well protected (at some sides) against modern AT-weapons.

 

[Toptob]

I want to add that:

most of the forementioned technical problems can be solved, and I dont think it would even be that hard (although I'm not a defense expert offcoarse).

But more importantly then all of that is the fact that most country's hardly ever use the tanks they have now. And I cant really imagine a situation where you would need a tank the size of a lorry.

so IMHO the most important reason why there are no tanks of the type you talk about is that they are not needed. No one wants them and no one has a situation in which they are needed.

To answer your question:" why can't they build such tanks?"
I'm sure such a tank CAN be built, but there's no reason they should be built.

To illustrate: would you want a laptop that can do the same as a super computer? No you dont, because you don't need that computer power in a portable computer, and it would have the size of a car and the battery would be the size of another car.

 

[Bonza]

I keep hearing how MBT's are basically at the upper limit of how big and how heavy they can be build.
At least it's said that you can never build a tank heavy enough with conventional armor to defeat modern anti tank threats.
I've heard that there wouldn't be a road able to support such a tank. but i never knew tanks were supposed to use roads to begin with.
Anyway i'm curious as to why tanks can't simply grow to battleship size?
Certainly having more armor would eventually make it unfeasible to use shoulder launched anti-tank missiles due to the shear weight of the explosive charge required to breach the armor.

But basically my question is, why can't they build such tanks? As i don't think it's a technological problem, there is something else , i also don't believe it's to do with being unable to use roads since tanks were never intended to use them in the first place.
A tank simply goes over and through things

Anyone have any thoughts on this? Thanks.

Circa WWII, the Germans had some plans for "super heavy" tanks, the Landkreuzer P. 1500 Monster and P. 1000 Ratte. There's a bit of information on the web about them, I'm at work and don't have time to hunt up some proper links for you but here's a couple of wiki pages you could use as a starting point for finding more information.

Landkreuzer P. 1500 Monster - Wikipedia, the free encyclopedia
Landkreuzer P. 1000 Ratte - Wikipedia, the free encyclopedia

Wikipedia's useless as far as serious references go but for convenience's sake I'll leave you with those. The limitations of the designs should make themselves immediately apparent - as other posters here have outlined - and I believe it was Speer who put a stop to both the Monster and Ratte projects due to their marked lack of practicality before anything came of them.

Still, as historical oddities they're interesting. Hope the links are helpful.

 

[Feanor]

I should add in terms of real giant tanks, the T-35 takes the cake and it was so impractical, complex, and unreliable, that only iirc 40 of the monsters were ever built, and most were lost due to mechanical issues or just plain abandonment.

 

[Toptob]

I believe it was Speer who put a stop to both the Monster and Ratte projects due to their marked lack of practicality before anything came of them.

Wikipedia says about the Monster that it's purpose was to knock out fortifications on long distances. To illustrate my point that such a large vehicle is not needed:

M270 Multiple Launch Rocket System - Wikipedia, the free encyclopedia

With normal rockets the MLRS has a range of up to 42km against the Monster's 32km, and with cruise missiles a range of 300km.
So apart from the obvious limitations, I think the Germans who where ( and are) a very intelligent people must have seen that a mobile V1 launcher would have made much more sense.
Also would the Monster have needed all that armor when it was that far behind the lines?

And what other battle scenario's would you imagine a tank that size would be usefull? The much smaller Maus was made to use the 128 mm KwK44 L/55 cannon, The Leopard 2A6 uses the 120mm rheinmetal smoothbore cannon, you can read about that in tank topics across this forum, but it seems a pretty effective weapon to me.

BUT!! If this can be built Big Muskie - Wikipedia, the free encyclopedia I'm pretty sure a tank can be built that could withstand a Nuke and keep a brigade alive for a month. That would be pretty cool, and you wouldnt have much use for bridges and roads in a nuclear wasteland. Furthermore a beast that size would use a lot of fuel but it could also carry a lot of fuel, but being the size of Belgium you could even fit a small nuclear reactor.

Then again, the likelyhood that such events would take place are very slim (thankfully). And I think having contingency plans is good, but that's a bit extreme.

Oh and I just thought of another reason such a tank could never be built. Think about the political stink it would cause if a government would declare they where going to build a 14 thousand tonnes nuclear powered hypertank.

 

[Feanor]

Oh and I just thought of another reason such a tank could never be built. Think about the political stink it would cause if a government would declare they where going to build a 14 thousand tonnes nuclear powered hypertank.

No more then the political stink of ~10 100000-ton nuclear-powered supercarriers.

 

[Waylander]

Current mechanized forces are already able to survive on a nuclear battlefield.

And what makes you think that one doesn't have to get over rivers in a nuclear environment.
Another problem is that one just cannot armor such a monster against something like a 2000lb LGB bunker buster. I doubt even against normal 500-1000lb bombs. Such a beast is a prime target and dead meat if one bomb carrying jet comes through.

 

[kato]

you could even fit a small nuclear reactor.

A reactor of similar size as on a carrier would bring you only 100 MW. A tracked vehicle to the tune of 10-15,000 tons can move at maybe 4-5 km/h with that energy. Of course the reactor and steam plants by themselves will already weigh around a third of that total...

 

[Feanor]

Current mechanized forces are already able to survive on a nuclear battlefield.

And what makes you think that one doesn't have to get over rivers in a nuclear environment.
Another problem is that one just cannot armor such a monster against something like a 2000lb LGB bunker buster. I doubt even against normal 500-1000lb bombs. Such a beast is a prime target and dead meat if one bomb carrying jet comes through.

Provided it doesn't have it's own SAM batteries mounted on it.

 

[Waylander]

Maybe one could just bolt a Burke superstructure onto it...

 

[Toptob]

And what makes you think that one doesn't have to get over rivers in a nuclear environment.

Never said you didnt, but you dont have to worry about breaking stuff, because I'd imagine most stuff will either be destroyed or badly damaged anyway.

Anyhow, I didnt mean to say It would be a good idea to build a 15 thousand tonnes tank. I just wanted to illustrate that it could possibly be technically doable.

To return to my point, you dont need such a machine so the whole discussion of the usability is pointless. And anyway the question was if it was posible to make a really big tank with very thick armor. IMHO the answer is yes. (Although we would never use it ofcoarse)

 

[Feanor]

Maybe one could just bolt a Burke superstructure onto it...

Hehe. Even that wouldn't justify the size or price tag.

 

[kato]

the question was if it was posible to make a really big tank with very thick armor.

The armour wouldn't really be thick.

A 15,000 ton tank would in essence be a current tank with all its dimensions inflated by a factor of six. Presuming we do not mount some oversized things like a nuclear reactor (which would probably take 3-4 times the size of the requisite gas turbines for the same output).

That factor six won't even give it enough protection against attacks with missiles like a Kh-29 or AGM-65 (except from the front, and the AGM-65 is top-attack anyway). Nevermind a BLU-109, HOPE, BROACH, MEPHISTO or AUP slamming into it. Probably useful against guided bomblets like SADARM, BAT or SMART though.

 

[Go229]

We're thinking OGRE here, i can smell it. Let me just remind everyone that OGREs run on miniaturized fusion reactors, are protected by a force shield as well as a supermegahardunobtainium hyperalloy and have a full AI. We're some time away from those breakthroughs

 

[luccloud]

I keep hearing how MBT's are basically at the upper limit of how big and how heavy they can be build.
At least it's said that you can never build a tank heavy enough with conventional armor to defeat modern anti tank threats.

You can have all the amour in the world, but your enemy can still easily take out its track and render it as a really expensive artillery.

 

[Dave62]

Wikipedia says about the Monster that it's purpose was to knock out fortifications on long distances. To illustrate my point that such a large vehicle is not needed:

With normal rockets the MLRS has a range of up to 42km against the Monster's 32km, and with cruise missiles a range of 300km.
So apart from the obvious limitations, I think the Germans who where ( and are) a very intelligent people must have seen that a mobile V1 launcher would have made much more sense.
Also would the Monster have needed all that armor when it was that far behind the lines?

And what other battle scenario's would you imagine a tank that size would be usefull? The much smaller Maus was made to use the 128 mm KwK44 L/55 cannon, The Leopard 2A6 uses the 120mm rheinmetal smoothbore cannon, you can read about that in tank topics across this forum, but it seems a pretty effective weapon to me.

BUT!! If this can be built I'm pretty sure a tank can be built that could withstand a Nuke and keep a brigade alive for a month. That would be pretty cool, and you wouldnt have much use for bridges and roads in a nuclear wasteland. Furthermore a beast that size would use a lot of fuel but it could also carry a lot of fuel, but being the size of Belgium you could even fit a small nuclear reactor.

Then again, the likelyhood that such events would take place are very slim (thankfully). And I think having contingency plans is good, but that's a bit extreme.

Oh and I just thought of another reason such a tank could never be built. Think about the political stink it would cause if a government would declare they where going to build a 14 thousand tonnes nuclear powered hypertank.

Yes, I use caps lock excessively. I have a problem.
Big Muskie is a GREAT example of how TERRIBLE of an idea it is to build such a large tank. That thing HAS TO HAVE ITS PATH PREPARED FOR IT. It the ground excessively soft/wet? Looks like we're not moving today. It moves EXTREMELY SLOWLY. It CAN'T HANDLE SIGNIFICANT SLOPES. It MUST BE DISASSEMBLED AND REASSEMBLED FOR RELOCATION, at least similar excavators are. Big Muskie never left Ohio. Big Muskie has no armor and its still has all of these problems. Removing the shovel and putting a battleship battery on it with tons of fuel and ammunition and food and nuclear reactors isn't going to save any weight at all. You will not be able to have more armor than a normal tank. It's not like ships. The larger the ship, the deeper it goes into the water and the more buoyancy it has per horizontal area of the ship. On land, the ground provides the same amount of support per area no matter how tall you are, so the taller a tank is, the less armor it must have.
Also, you need to be able to use roads. Rivers, mountain ranges, buildings, these all significantly slow you down if you try to drive through them. Luckily, we have bridges, tunnels, and streets to get around them, but you have to be able to not break a bridge, not hit the roof of a tunnel, and not be too wide for a street.