That is the commonly given explanation. The theory went that poor welding quality resulted in a relatively high ductile-to-brittle transition temperature, such that North Atlantic and Arctic service would render the welds brittle. It’s only half the story though, as fatigue cracks from sharp hatch corners were probably the initiators of many of the failures, and the early liberty ship designs weren’t very good.
http://matdl.org/failurecases/Other%20failures/liberty_ships.htm
I thought that the Liberty Ship concept was that whether they were made of steel or concrete, they could be built faster than they could be sunk by accidents or Germans.
Yes, standardization based on a model supplied by the British. Regardless of the flaws in early implementation, it was a clever idea, well-suited to the situation. The Germans were obsessed with quality mechanisms, tuned with endless variants. The Nazi maintenance problems were substantial, because parts were so often not interchangable. So the last thing they expected was that America, which was much stronger industrially than they realized, would standardize on a somewhat so-so product, made in huge numbers. It caught Nazi planning right where it was so vulnerable almost nothing could be done.
The “build faster than can be sunk” concept does reflect the ideas of the time, but Clay Blair in his detailed analysis shows the Nazi’s at no point came close to cutting off supplies to Great Britain. Practically no American troops were lost crossing the Atlantic. The U-boats were a terrible failure.
This vaguely relates to the original topic, too, which is whether is was a bad idea to rivet tanks. It was, but American tanks were so lousy, especially at the beginning of WWII, the rivets were only part of the problem. The armor was miserable, the guns marginal.
Good point-the Porsche-designed “Panzerjager” (tank hunter) “Ferdinand”/Elefant was an interesting design-when it worked (its long barrel 88 mm cannon could destroy any soviet tank at long range).
But its diesel-electric drive mechanism had a very short life-it would break down after 25-30 hours. A lot of them were abandoned, because they could not be easily repaired.
Had the Germans massed produced a good design like the T-34, they would have been far better off-spare parts supply would have been easier
The same with the Lufwaffe-would you like to be the pilot of a JU-87 Stuka (facing a Spitfire or Mustang fighter plane)?
Well, they DID mass-produce a good design for the Luftwaffe. More Bf-109s were made than any other fighter aircraft in human history. It was a flexible platform that supported many upgrades over the course of the war, and although the late-war models were outclassed by many Allied aircraft, they weren’t toally outclassed and in many matchups remained dangerously competitive.
They were a smashing success actually. They were so dangerous they prompted things like Liberty Ships getting built in massive numbers and a massive effort in thwarting them (Blechley Park was largely committed to decrypting Enigma to thwart U-Boats…this was no small effort and it was not done because the U-Boats were really failures).
Germany’s mistake with the U-Boats was they did not start with enough of them. Karl Doenitz wanted 300 at the start of the war (enough to have 100 at sea at any given time). He got 55 and only 12 were at sea at any given time.
By the time the Germans got serious about U-Boat production it was too late. The Allies had developed answers to the U-Boats and eventually the U-Boats became a death sentence.
At the outset though they worried the Brits big time. If Doenitz had his 300 at the start the Germans may well have choked the Brits to death and forced them to negotiate a truce.
The war would have been very different then.
While we’re on this topic …
Someone has already mentioned that welding was a relatively new technique, hence the “no brainer” engineering decision to use rivets.
But here’s something that’s always bothered me: Why weren’t American tanks better armored? The Germans had some kind of excuse: Their resources were being stretched. The metals to make a better armor alloy were expensive and in short supply.
But it’s generally recognized that the America had huge resources, compared to Germany. I suppose that must have included steel and alloys. Perhaps a sufficiently powerful engine was a problem. Use two engines, then. It had been done before.
Why did America not send the equivalent of a Tiger II to North Africa. Nothing could have stopped it. 500 of them would have cleared Africa.
So, what’s with all the pantywaist armoring??
Tank design is the art of tradeoffs.
At the outset of the war the Sherman was sufficient against the Panzer II & III. It was wholly inadequate against the Panzer IV and Tiger later on.
But, as Stalin quipped, quantity has a quality all its own. Shermans could be produced in large numbers and was a reliable tank (heck, I have heard stories of Sherman crews killed by a German tank, they’d hose out the inside, patch the hole and send that tank out again).
So, sucked for the tank crews but overall the Sherman was pretty successful. A better tank in fewer numbers is not necessarily better. The King Tiger was apparently a beast and a terror on the battlefield (Russian tankers took to ramming them since that was about all they cold do to them). But the King Tiger was unreliable, expensive as hell and never made in useful numbers. So, while more than a match for any tank in WWII it was largely a failure.
Fuel economy is also important. A Sherman got almost 1 MPG whereas the big German tanks used 2 or 3 gallons per mile. That means you can put a lot more of them in the field with a given supply chain.
The M4 sherman was designed in 1940 in response to German tanks used then. In 1940 German tanks typically had 30mm of armour at thickest. The frontal armour on a sherman which was designed in response to what they’d seen in 1940, was around 50-65mm thick.
You can’t just add weight on a tank without it hitting other areas of performance. A lot of later war heavy German tanks had serious reliability problems.
Plus there’s the problem of shipping the things across the Atlantic, then across the Channel. Moving them over railways, through tunnels, over roads and bridges.
The US did have a heavier tank than the M4 sherman, the M6
But there’s more to a tank than just having thick armour. And the problems it had in other aspects of performance, plus the difficulty of transporting the things, killed the M6 and it never saw combat.
Death Traps A great book about Sherman Tanks.
Funny. I just started reading that book last night.
As for Shermans not stacking up against panzers, remember that the US tanks did not operate in a vacuum. Tank destroyers like the M10 or later M36 were used to provide fire support to armored columns. A Tank Destroyer was only lightly armored but had a big gun, 3-inch or later 90mm. So it would hang back behind the Shermans and try to blast whatever the Shermans couldn’t take on.
Yeah, but the tank destroyer concept, as imagined by the US, never really worked. The original idea was that the fast Shermans would charge on ahead through gaps in the enemy lines (classic blitzkrieg), while there would be a central reserve of tank destroyers which would be thrown into the fray once a sizable force of enemy armor showed up. The problem was the inherent lack of flexibility involved for both types of units-the US tanks were good for gobbling up ground, but ill-pressed to handle enemy tanks, while the TDs were pretty worthless against infantry, but could handle the tanks (but even then only on the defensive typically). By dividing the roles between two types of armored vehicles they made them both sub-optimal (and even then the armor of the TDs was pretty poor too).
The British discovered this with their “cruiser” and “infantry” tanks-the cruisers would charge on ahead and gobble up ground, while the infantry tanks would plod along with the infantry (natch); the cruiser tanks however couldn’t handle enemy tanks with their thin armor and crap guns, while the infantry tanks were worthless on the attack with their slow speed.
The Germans of course had tank destroyers too, but they still had plenty of regular tanks which had good all-around performance and could kill their enemy counterparts. Note that the US had the Pershing, which was a rough equal to the Panther, but certain parties (mainly Gen. Lesley McNair) in the US Army hierarchy kept the Pershings from being allocated sufficient development, training, and deployment time until the war was almost over, precisely because the brass responsible didn’t think that a big-gunned main battle tank would be necessary, given the existence of the tank destroyers.
Yes, the use of TDs as fire support for the advance was an ad hoc development. In fact, just about every way they were actually used after their first few combat experiences was an ad hoc measure. The TD crews realized they couldn’t perform as originally envisioned and found roles that let them contribute meaningfully to the battle. As the war progressed, greater coordination was encouraged between the TDs and the units they supported, both infantry and armor.
The author of the aforementioned Death Traps book lays the blame for the delay in M-26 deployment firmly at Pattons feet. Patton didn’t know how fast and nimble the Pershing was and therefore wanted to keep his fast breakthrough tank, the Sherman.
As I recall, the Shermans did have certain advantages (BTW, the M3 Lee? I love how wacky that design is, with the gun sticking out of the corner of the body like that. Does make for an interesting precursor to the M4 though, if you look at the lines). Amongst them was that they were relatively very mobile compared to the German tanks, and the lighter weight of their gun made it easier for them to use that mobility (granted, they couldn’t reliably do much damage with those guns). Later models included larger guns, but were never used in large numbers, instead being used as a supporting role, like the one machine gunner in the squad of riflemen.
And the argument I was always told for not switching to the Pershing tank was that they were concerned that stopping production of the M4 while the factories retooled to start churning out the M26s might cause too severe a break in production, giving the Germans valuable time to even the playing field.
As far as spalling goes, I understand that one common solution eventually used was to line the interiors of modern armored vehicles with kevlar or similar materials to catch the fragments.
And as far as tank destroyers go, the concept is still alive, if not in the exact same way, with vehicles like the Bradley IFV, which carry anti-tank missiles that give them the capability to get in a couple of cheap shots at long range (which suited the original intent of the Bradley well: They’d scout ahead, use their missiles against whatever enemy vehicles they encountered, disgorge the infantry that would support them in combat against the enemy, and use their 25mm gun to lay down supporting fire until the tanks caught up to wherever the fight developed. Kind of flipping the roles of tank and destroyer around, but then missiles are kind of a force multiplier.
The biggest advantage of the Sherman was its producability.
The Sherman certainly wasn’t the best tank during the war. The German Tiger II could put a shell through the front and out the back of the Sherman (which wasn’t very pleasant for the crew in the middle). In contrast, the Sherman couldn’t penetrate the front armor of the Tiger at all. To kill a Tiger, a Sherman had to get behind it and shoot it in the ass (while certainly not a documentary, the movie Kelly’s Heroes featured this as a plot point). The Shermans quickly earned the nickname “the Ronson”, after a cigarette lighter whose advertising slogan at the time was “lights the first time, every time”.
On average, it took four Shermans to take out a single Tiger. But, and this is the key to it all, we could produce ten Shermans for every one Tiger that they could produce. So yeah, life sucked for three out of four of those Sherman crews, but in the end the Germans had less than half as many tanks as they needed to even have a chance.
The Russians followed the same principle. The T-34 was a better tank than the Sherman (IMHO) but it was still very much outclassed by the German tanks it fought, so much so that the Russians occasionally resorted to simply ramming the German tanks out of desperation (a tactic that surprisingly worked, more often than not). But even though the T-34 was outclassed, the Russians sent in tank after tank after tank until the Germans were simply overwhelmed.
Having the best tanks cost Germany the tank war, which is kinda ironic if you think about it. Those superior tanks simply were too difficult to produce in large numbers.
Another important factor was tactics. The Americans knew their tanks didn’t do well when they went head to head with the German tanks, so the Americans simply avoided doing that whenever possible. Instead of fighting tank to tank, they fought army to army. They went after the supply lines, the fuel, the ammunition, the support mechanics, spare parts, etc. Without all of that, a tank is just a big expensive piece of metal.
Five was generally the number assumed to be needed to knock out a Tiger, according to what I’ve read.
Agreed, but you’re understating the case.
1,347 Tigers
49,234 Shermans
That’s thirty-six times as many Shermans. 
I’m going to differ with you on this one. The T-34 was better than anything the Germans had when they first encountered it. “We had nothing comparable,” wrote Generalmajor Friedrich von Mellenthin, in Panzer Battles.
The upgraded T-34 85 was qualitatively equivalent to the German Panther. Last fall the History Channel showed tank-related programs all day for “Tanksgiving,” (:)) and two different lists of Greatest Tank Ever differed in placing the T-34-85 above the Panther and vice-versa. The Germans had far superior optics and a somewhat superior gun; the T-34 had the edge in maneuverability and reliability. The much-quoted stories of “resorting to ramming” occurred when the Soviet tanks met the German heavyweights – Tigers, King Tigers and Ferdinand/Elefant tank destroyers. While impressive, those (especially the super-heavies, other than the Tiger itself) were never built in militarily significant numbers – 492 King Tigers and only 91 Elefants (numbers from Wikipedia).
Certainly the Soviets built in huge numbers, but they had excellent tanks from 1942 onwards.
I have also read that the German tanks were difficult to repair-such that a large number of damaged tanks had to be abandoned.
The supply problems encountered by the German Army in Russia must have been overwhelming-they actually had to use horse-drawn carts to drag spare tank parts from the railheads.
Plus, having to repair a tank engine in the open…in the freezing winter could not have been fun.
Which makes me wonder how the Luftwaffe in Russia fared-they flew from open fields without the luxury of heated hangars-that surely was a big factor in their defeat.
Wow! This thread makes me want to pick up a book on the subject and get up to speed.
Y’all are amazing! And you know what is really cool? The tone has been respectful and informative even when posters disagreed with each other. A genuine relief after reading other less well-mannered threads (elsewhere not on SDMB).
I really love this place.
Thanks.
PS: I learned a new word, ‘spalling’, reading this. The idea that even if a hit didn’t hole a plate it still caused significant damage is quite interesting to me. Most of my war-gaming has been medieval or classical, so such details were unknown to me. I probably should have spent more time playing WW2 simulations. 
That’s what spalling is scientifically - breakup caused by a shock wave from a projectile.