The Saint-Chamond tank could travel at about 7.5 miles per hour, which was surprisingly fast back then, but the hitch was that it could only do it over flat terrain. So what happened when the ground got rough?

The Achilles Heel:

Take a look at that tank for a moment. Even though you are not a master tank engineer, you may have noticed that, "Hey, the nose of that tank is awfully long. What happens when that tank has to ford rivers or trenches?"

landships
"Look, I'll get out and wave you back a bit. No, no, you don't f*****g blame me for this."

Since most WWI battles weren't fought in parking lots, this tank was only slightly more ineffectual than the tank it replaced, thanks largely in part to that massive appendage on the front, which had a tendency to dig straight into the ground and get the whole tank stuck.

Whenever the tanks surged across the battlefield, they would quickly and comically stumble over craters, mounds or just about any slight change in elevation, and since the gun couldn't rotate or elevate at all, the only thing it could do was shoot at the ground. So while it may have been useless against other vehicles and humans, the tank was very dangerous against enemies like dirt and mud.

Wikipedia
"s**t. It's a hill -- get out the white flags."

If they ever did make it all the way across, they got stuck when their noses dug into German trenches, because they had slightly widened them specifically to f**k with these tanks. Yeah, that's it. No super gun, no giant antitank flamethrower, no giant-ass mines, just a little extra digging and this massive weapon became obsolete.

The king believed that "Second to God, the welfare of the kingdom depends on its navy." The Vasa was the largest wooden ship ever to set sail. Which it did, exactly once.

The Achilles Heel:

On the day of its maiden voyage, thousands of Swedes turned out to see their newest and grandest warship ever set sail for the first time. After four years of painstaking construction, the Vasa launched from port, fired its guns in salute and promptly fell over.

perdurabo
"THAT'LL LEARN YOU, EXCITED CROWD."

As it turns out, trusting your entire design to the king instead of someone whose actual job is making ships is a terrible idea. When the Vasa encountered its first wind only one nautical mile into its maiden voyage, the whole thing tipped over and sank. To put it simply, the biggest and most expensive sailboat ever built hadn't accounted for the possibility of wind.

The problem was that the portholes for all the cannons were so close to the waterline that as the ship swayed in the first gust, half the ocean flowed freely into its underbelly. The ship was later raised from the depths and dragged to a museum, presumably as a warning to other monarchs about meddling with s**t they don't understand. Also because that sad pile of wood was the height of Sweden's naval power. Thousands of people who thought they would only witness the rise of the Swedish navy instead got the bonus of seeing its fall as well, all in one sitting.

Wikipedia
The Swedes are a notoriously punctual people.

What could be sadder than that? How about failing to learn its lesson almost four centuries later ...

The Achilles Heel:

The ship was so ridiculously top-heavy that it physically couldn't turn more than 10 degrees without tipping over and dumping everybody into the water.

Don't get us wrong: If you were an enemy facing this thing, you were in serious trouble, provided you stayed in one place and it was the direction the ship was already headed. The Tegetthoff Class battleship was like the rhinoceros of the sea.

cityofart
In that it sunk straight to the bottom.

Amazingly, there were still four of these ships built without modifications to fix this rather serious problem. So the Austro-Hungarian navy faced two options: a large and expensive refit and overhaul to the ships that would redistribute the weight, or just avoid turning, ever. They decided to go with the latter and banned sharp turning on all four ships.

Naturally, this meant that the ship was ridiculously easy to sink as long as you could get it off-balance, because even the slightest amount of water onboard would cause the ship to capsize. And worse, the ships had virtually no underwater protection. So in 1918, when the SMS Szent Istvan was hit by an enemy torpedo, it wasted no time in going belly-up, despite such drastic measures as counter-flooding, throwing all ammunition overboard and turning the giant guns sideways.

Wikipedia
"What about the crew?" "Good idea, get rid of them, too."

Oh, and to add embarrassment, the whole thing is caught on film.

And, in fact, the first prototype broke the world airspeed record for 1953. Unfortunately, after the designers got the "fast" and "looks cool" parts down, they decided to call it a day.

The Achilles Heel:

The Hawker Hunter could only stay airborne for about an hour, which meant that if anything went wrong with the flight plan, it resulted in an immediate emergency. But that was the least of a pilot's worries when flying one of these to intercept a bomber.

planeshots
Maybe they should have spent a little more time on those blueprints and a little less time color-coordinating.

If the thing was flying high enough, firing the guns would cause the engines to surge and catch fire before crashing. Its own engines. The guns were positioned in such a way that the exhaust and shell casings would fly right the hell back into the spinning metal blades keeping the plane aloft.

As a result, 30,000 feet was about the limit at which the interceptor could safely fire its guns, and incidentally that's about 10,000 feet below the cruising altitude of nearly every bomber in the 1950s. So, like a giant steel bumble bee, the Hawker Hunter couldn't destroy anything without killing itself, too.

Wikipedia
"That's a great height. Just keep it there for a sec."

We guess this isn't as silly as if they had, say, positioned important parts of the plane in front of the guns, because that has happened, too ...

And even though it likely wasn't intentional, in the case of the De Ruyter, the anti-aircraft guns had to shoot the ship before it had any chance of hitting the enemy.

The Achilles Heel:

The cruiser had originally been designed to be much more powerful, but the pacifist movement in the Netherlands had greatly reduced the armament on board, to the point where the anti-air capability was all limited to one cluster of guns on one side of the ship. Here's a little diagram to help you understand exactly why that would be a problem.

We drew this diagram drunk, and it's still better than the Dutch attempt.

The anti-aircraft guns were perfectly lined up to shoot right through the bridge, or as those of you who don't watch the History Channel or Star Trek might know it, that place where senior officers and commanders hang out. It was either that, or just let the aircraft attack head on, since there was virtually no anti-aircraft armament that could protect the front of the ship.

Naturally, the De Ruyter didn't last very long in World War II. It was sunk quickly during its first major engagement in the Battle of the Java Sea, showing just how much military might a nation of pacifists contains.

machuproject
"OK, just ... wait until it comes around for another pass, then toss the wrenches at it."

The Achilles Heel:

The biggest problem was that there was no separation between the engine and the crew compartment. That would be the equivalent of installing a car's motor in the passenger seat, and then sealing all the windows and vents with steel. The massive amounts of carbon monoxide pumping out from the engines of the Mark I would sometimes cause entire tank crews to pass out in the middle of combat.

Wikipedia
"Aw. All tuckered out. Seal it back up."

As the British designed newer versions of the tank, they never bothered to take care of the biggest and most dangerous problem. Instead, they upgraded the Mark I to a troop carrier by extending the length, but the troops were completely useless wherever they arrived thanks to the severe carbon monoxide poisoning. In addition, the temperature could also get up to 120 degrees inside, causing some soldiers to get heatstroke in addition to huffing toxic fumes. If WWI had been against raw meats and frozen pizzas, Britain would have won the war single-handedly after inadvertently developing the most deadly and durable oven ever conceived.

Wikipedia
"Just surrender the whole lot to the Germans and let nature take its course."

For more ridiculous weapons of war, check out 6 New Weapons That You Literally Cannot Hide From and The 6 Most Badass Weapons Ever Improvised in Battle.

And stop by LinkSTORM to learn how to arm yourself properly against Santa Claus.

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