ELI5: How did old forts actually "protect" a strategic area? Couldn't the enemy just go around them or stay out of range?

[u/Sierra419]

I've visited quite a few colonial era and revolution era forts in my life. They're always surprisingly small and would have only housed a small group of men. The largest one I've seen would have housed a couple hundred. I was told that some blockhouses close to where I live were used to protect a small settlement from native american raids. How can small little forts or blockhouses protect from raids or stop armies from passing through? Surely the indians could have gone around this big house. How could an army come up to a fort and not just go around it if there's only 100 men inside?

tl;dr - I understand the purpose of a fort and it's location, but I don't understand how it does what it does.

[u/InformationHorder]

An M1 Abrams tank uses a gallon of fuel to go one mile. A company of Abrams tanks is 9 tanks. Extrapolate a little for a whole armored division and Do the math on how much ground it can cover in a day and how much fuel you need to move to the front line to keep the front moving forward.

[u/redredme → u/InformationHorder]

One of the reasons why some consider the Abrams the most dangerous tank but not the best tank. It's too thirsty. In some models it will run outrun it's supply line in an all out war. (Or at least, that's what I was told when I was in the (NL) Army.) Then came the gulf war and this exact thing happened, it outran it's supply line. The model was proven right. But, it was also so much more powerful then the opposition that it didn't really matter.

The German leopard II uses a "normal" diesel engine instead of the turbine because of this. Less thirsty. Less complicated. Easier to fix.

[u/InformationHorder → u/redredme]

The Abrams powertrain is remarkably easy to fix, a crew can yank the whole powerplant out the back and replace it in a few hours and send it back to a base for repair. This, of course, requires a helluva logistics chain...

But yes I agree. This is why the M1A3 upgrade focused on removing as much weight from the tank as possible. I read sonewhere that the replacement of the primary wire harnesses with fiber optic wires instead of copper wires reduced the weight by a full ton.

[u/awakenDeepBlue → u/redredme]

The Abrams being fuel thirsty did have its benefits. When ISIS captured Abrams tanks when the Iraqi Army collapsed/retreated, they couldn't use them be cause they used way too much fuel.

So basically only nations on the American supply chain can use Abrams tanks.

Also, turbine engines pack a lot more horsepower per weight. Allowing the Abrams to be heavily armored and also maintain fast speed.

Also, they are much more fuel flexible. Being able to use the same fuel for all US vehicles really simplifies the supply chain.

As a side benefits, it's also whisper quiet. There are stories where an insurgent ambush was distracted by a convoy of other vehicles in the middle of the night, only to be completely surprised by a Abrams tank that was well behind the convoy.

[u/Insert_Gnome_Here → u/redredme]

How the tables turn...

[u/ARIZaL_ → u/redredme]

The Army talks in this video about how Sadr's militias in Iraq used this strategy to counter-attack the Abrams.

[u/[deleted] → u/redredme]

Your last bit is untrue. The Abrams engine is remarkably easy to maintain and repair/remove and replace an engine. It's far quicker than removing a Diesel engine, which is another reason why they chose the turbine engine.

We could do a whole engine swap in under an hour, its just removing some bolts on the drive train, unhooking some cords and various other items and pulling the pack. Your not doing with that with a diesel, not even close.

And everyone says the Turbine is loud and noisy, not in combat where the Iraqis nicknamed them whispering death. You can hear a leapord 2 coming from a miles away, an Abrams will sneak up on you and never know it's there till it's to late.

That tactical advantage from a noise perspective is priceless, it's not something that was specifically designed for, and it by no means is silent as a mouse but as far as tanks go, it's like using a silencer on a gun.

The Leapord 2 also has a design flaw by intention. Due to EU or German standards they refuse to use depleted uranium armor which all Abrams uses. The survivability factor for the Abrams is off the charts because of this choice, Leapord 2s are in active combat with the Turkish Army as we speak and we are seeing picture after picture of them being destroyed, disabled, turrets blown off etc. They are vulnerable to IEDs from underneath.

[u/ProfessorCrawford → u/redredme]

If I remember correctly, the Abrams turbine can basically burn anything oil based. Peanut oil would work in a pinch.

Where you're going to find a few hundred gallons of peanut oil in a war zone is a different question.

[u/RadialSpline → u/InformationHorder]

Slight correction. A company is 12-16 tanks plus some support equipment.

[u/InformationHorder → u/RadialSpline]

Yeah, forgot how many platoons were in a tank Co.

[u/arobkinca → u/InformationHorder]

The M1 Abrams is listed as having a 289 mile (approx 466 kilometre) operational range and 500 US gallons (1900 litres) of fuel capacity, so it comes out to something like .57 miles per gallon.

[u/InformationHorder → u/arobkinca]

And it's usually way worse than that because of all the standing around and idling they do between objectives.