Groundhog Thread v. 2.0 - The most important battle of WW2

Ad: This forum contains affiliate links to products on Amazon and eBay. More information in Terms and rules

My source is Rahn ''Combat Readiness and Combat Power of German Submarines P 80 ,cited by Magenheimer in ''Hitler's War on P 132 .
You do realize that Magenheimer is a devout revisionist, right?
Many of his writings have been discredited by the academic community on verious levels.
 
Yeah, I didn't mean that broken ciphers gave away all info, all the time. That is exactly why I added the caveat "when the Allies were able to read German mail."

I had thought such wording would make clear that the Allies weren't always able to decipher and/or reroute.
But , you are still focusing on the number of supplies that was lost by submarines, while this number is subordinate on the number of supplies that arrived in Liverpool .
ONE example :
the period September 1939-May 1940 :
the month with the highest losses was May 1940 : 220,127 GRT were lost and the month with the lowest losses was November 1939 : 53,511 GRT .
Thus : May was the worst month and November the best ? NO
Because in May 5,142,000 GRT arrived in Britain : 5,362,000 were sent and 220,000 were lost
While in November 4,408,000 were sent and 53,111 were lost, which means that only 4,355,000 GRT arrived .
Thus May was better than November .
Other point : it was not the amount of supplies that was lost,that was important, but WHAT was lost . If in November all losses were oil,that would mean that Britain could be in trouble with only 53000 GRT that was lost .
Last point : it was even (theoretically ) possible that Britain could be in big problems without losing even ONE ton of supplies : as everyone knows (or should know ) : all ships that arrived in Britain had to return empty to the Americas or the harbours from where they were sailing.
If in a month 1000 ships left for Britain with 3 million ton of supplies, and if all arrived without losing any GRT ,but if all were lost on their return, Britain would be in big problems .
I know that this IF did not happen , but he indicates that it is wrong to look at the losses of supplies only ,and also that it is wrong to look at the number of supplies only : Britain would be hurt more by the loss of 100000 GRT of oil than by the loss of 200000 GRT of Spam.
It is also wrong to look at the losses of U Boats only,as more U Boats were not a bigger danger than less U Boats .
Question :
was it possible for U Boats to recognize oil tankers ?
If yes, why was not more oil sunk ?
If not : why did Doenitz nothing to make it possible to recognize oil tankers ?
 
You do realize that Magenheimer is a devout revisionist, right?
Many of his writings have been discredited by the academic community on verious levels.
I do mostly disagree with Magenheimer, but the figures about operational U Boats,are not his figures, but those of Rahn .
 
What losses ?
Losses of U Boats ? These can not be used to argue that the situation changed .
Losses of MV: idem,because there were loaded MV and empty MV.
Losses of supplies ? idem : a loss of 100000 GRT supplies can be more dangerous than a loss of 200000 GRT .
What is important is not how many supplies were lost but WHAT supplies were lost .
And, what is decisive is WHAT arrived in Britain and the number of ships that returned in the Americas .
 
What losses ?
Losses of U Boats ? These can not be used to argue that the situation changed .
Losses of MV: idem,because there were loaded MV and empty MV.
Losses of supplies ? idem : a loss of 100000 GRT supplies can be more dangerous than a loss of 200000 GRT .
What is important is not how many supplies were lost but WHAT supplies were lost .
And, what is decisive is WHAT arrived in Britain and the number of ships that returned in the Americas .
That is what you say, I dont agree. What was decisive was the number of U Boats sunk compared to U Boats made and crews trained on one side and the tonnage of shipping lost on the other compared to how much was launched.. The fact that you talk about selecting tankers to sink shows you havnt thought about it much.
 
Last edited:
But , you are still focusing on the number of supplies that was lost by submarines, while this number is subordinate on the number of supplies that arrived in Liverpool .
No, I'm not. I'm saying that the ability to get the supplies over to the UK was the Allied victory condition. I'm not sure where your confusion is arising, but I'm sure you're confused about my point, which is that decrypts played a role in helping those ships deliver their cargoes. That was the entire point of all the measures the Allies took in the BotA: to ensure the safe delivery of cargoes. I should think it obvious that this is why rerouting was done.

Question :
was it possible for U Boats to recognize oil tankers ?
Of course.

If yes, why was not more oil sunk ?

Perhaps the firing solutions weren't handy for the U-boat skipper? Related -- perhaps the U-boat skipper didn't see the tanker(s) because another ship was blocking clear identification of said tanker(s)? Perhaps it had a tanker lined up and before it could launch torpedoes an escort charged it?

There are plenty of reasons why things go wrong in a battle. Clausewitz coined the term "friction" to explain how the exigencies of war can hamper military operations. It's a vital concept in understanding almost all battles one cares to look at.
 
Last edited:
No, I'm not. I'm saying that the ability to get the supplies over to the UK was the Allied victory condition. I'm not sure where your confusion is arising, but I'm sure you're confused about my point, which is that decrypts played a role in helping those ships deliver their cargoes. That was the entire point of all the measures the Allies took in the BotA: to ensure the safe delivery of cargoes. I should think it obvious that this is why rerouting was done.



Of course.



Perhaps the firing solutions weren't handy for the U-boat skipper? Related -- perhaps the U-boat skipper didn't see the tanker(s) because another ship was blocking clear identification of said tanker(s)? Perhaps it had a tanker lined up and before it could launch torpedoes an escort charged it?

There are plenty of reasons why things go wrong in a battle. Clausewitz coined the term "friction" to explain how the exigencies of war can hamper military operations. It's a vital concept in understanding almost all battles one cares to look at.
It may or may not be possible to tell what is a tanker at night though a periscope, how many ships should a captain let go before he sinks one, maybe the tankers are in another part of the convoy maybe there arent any tankers in the convoy. Having sunk a tanker how long do you stooge about looking for another or do you sink as many as possible as quickly as possible before the escorts get you?
 
It may or may not be possible to tell what is a tanker at night though a periscope, how many ships should a captain let go before he sinks one, maybe the tankers are in another part of the convoy maybe there arent any tankers in the convoy. Having sunk a tanker how long do you stooge about looking for another or do you sink as many as possible as quickly as possible before the escorts get you?

Exactly. The fog of war contributes to friction. Especially with subs and their tender hulls, loitering about to pick the optimal target doesn't strike me as a good idea.

I do remember that most submarines of the era operated on the surface at night, but that doesn't negate your larger point at all. Periscope or binoculars, on a sub we're talking about observers on a relatively low platform (restricting sighting distance) which may be sailing through swells (further reducing observational capability) in the dark (that's right, there's more reduction in observation) against ships which are generally sailing unlighted.

Even in daylight, surface ships were regularly misidentified. Now consider the manifold difficulties produced by night, and it's no wonder subs didn't hang around to pick out the juiciest cow in the herd for its shots.

You're dead right on this point.
 
Last edited:
Exactly. The fog of war contributes to friction. Especially with subs and their tender hulls, loitering about to pick the optimal target doesn't strike me as a good idea.

I do remember that most submarines of the era operated on the surface at night, but that doesn't negate your larger point at all. Periscope or binoculars, on a sub we're talking about observers on a relatively low platform (restricting sighting distance) which may be sailing through swells (further reducing observational capability) in the dark (that's right, there's more reduction in observation) against ships which are generally sailing unlighted.

Even in daylight, surface ships were regularly misidentified. Now consider the manifold difficulties produced by night, and it's no wonder subs didn't hang around to pick out the juiciest cow in the herd for its shots.

You're dead right on this point.
Tactics changed on both sides, before convoys a submarine may surface and use the deck gun to save torpedoes, armed merchantmen put an end to that malarkey. Many captains preferred to get inside a convoy and attack as it passed, but then escorts got wise to that and were waiting at the back.

But their arent really hard fast rules, different captains had their own favourite methods. I remember a U Boat captain on a documentary describing attacking a tanker, but it wasnt clear if he knew that before it exploded! There were special tanker designs but to me they just look like ships, a class of Liberty ship were tankers, they definitely look like all other Liberty ships.
 
There were special tanker designs but to me they just look like ships, a class of Liberty ship were tankers, they definitely look like all other Liberty ships.

I think the giveaways for tankers were: 1) they tended to ride lower in the water, and 2) the relative lack of booms on deck (for lading/unlading dry cargoes). Those two in combination would be a big aid in IDing, but of course can not and were not perfect. Expecting a sub skipper to hang around to be perfectly sure isn't really realistic, to me. When stealth is your main defense, you risk it only under dire circumstances, or if the enemy is unescorted.

Of course, the Japanese aerial recon at Coral Sea misidentified the tanker USS Neosho as an aircraft carrier, so there's that. S**t happens, especially in combat. Pictured below to illustrate the two ID points mentioned above:

nderway_at_sea%2C_circa_in_the_1980s_%286392656%29.jpg
 
Last edited:
More submarines in the Atlantic does not mean more losses of MV, but more loses of submarines .
If Doenitz said that with more U Boats he could prevent the US from supplying Britain, he was a fool :
Britain was not supplied by the US only
To have 80/100 U Boats active in the Atlantic, he would need more than 500 U Boats and this was excluded .
On 1 January 1942 there were 249 U Boats of which 158 for training,from the remaining 91 only 55 were available for the Atlantic and of these 22 were on patrol at any given time .
And, most important, and this proves that he was not a good U Boat commander : to force Britain to give up did not depend on the amount of supplies that arrived in Liverpool,as Britain was less depending on imports during the war than before the war .Britain had ONE weak point : OIL . If the U Boats were concentrating on the oil tankers,the situation could become dangerous for Britain , but Doenitz preferred to sink ships with spam ,to have his name mentioned in the Sonderberichten from Radio Berlin .
More submarines in the Atlantic does not mean more losses of MV, but more loses of submarines
I think you will find that the increased loss of submarines had something to do with little things. Such as the breaking of the Enigma codes resulting in every supply U Boat being sunk. . Convoys being re routed because we had a good idea as to where the U Boat packs were.

If Doenitz said that with more U Boats he could prevent the US from supplying Britain, he was a fool :
Now Donitz is the fool, when he was actually right. If he had started the war with the Italian submarine fleet deployed in the Atlantic instead of his handful of U Boats. There is a very good chance that he may well of succeeded.

And, most important, and this proves that he was not a good U Boat commander :
Now Donitz is a poor U Boat Commander. The man who introduced a whole new way of using the U Boat at war, very successfully. Was he perfect, no, did he get more right than wrong, yes, until the technology overtook him. I presume you don't have any qualifications or experience to to have the right to call him a fool or a bad U Boat commander.

To force Britain to give up did not depend on the amount of supplies that arrived in Liverpool, as Britain was less depending on imports during the war than before the war
Fundamentally wrong in almost every way. Without food imports the UK would have folded it was never even close to self sufficiency.

Britain had ONE weak point : OIL . If the U Boats were concentrating on the oil tankers,the situation could become dangerous for Britain
A common misconception but your statement is again, fundamentally wrong. The UK was never short of fuel. Actually I should correct that, There was a shortage of 100 octane fuel in May 1944. This was because the simply vast amount of fuel being used in the build up to the invasion, almost overcame the UK's ability to distribute it.

but Doenitz preferred to sink ships with spam ,to have his name mentioned in the Sonderberichten from Radio Berlin
A typical big statement with as ever no concept of the difficulty and pretty insulting to a man recognised by all sides as being someone who knew what he was talking about. The tankers were always kept in the centre of the convoys, so to sink them you had to get past the other vessels first. A tanker sounds just like another ship so you cannot hear the difference. If you keep the periscope up there is an increased chance of being seen and at night you couldn't see much through a periscope at night anyway. Go on the surface semi submerged worked at first (a Doenitz idea by the way, not used by any other navy) but when radar improved so that it was effective against such targets it was close to suicidal.
Maybe you could enlighten us all by telling us how you would do it.
 
More submarines in the Atlantic does not mean more losses of MV, but more loses of submarines
I think you will find that the increased loss of submarines had something to do with little things. Such as the breaking of the Enigma codes resulting in every supply U Boat being sunk. . Convoys being re routed because we had a good idea as to where the U Boat packs were.

While I agree with the gist of your entire response, I'm not sure that milch cows being sunk increased combat U-boat losses by much; rather, it reduced their radius of action and forced shorter missions, effectively reducing the combat strength of the Ubootwaffen without many additional sinkings.

In short, it was removing a force-multiplier that Doenitz had. Is there a short-circuit in my thinking?
 
While I agree with the gist of your entire response, I'm not sure that milch cows being sunk increased combat U-boat losses by much; rather, it reduced their radius of action and forced shorter missions, effectively reducing the combat strength of the Ubootwaffen without many additional sinkings.

In short, it was removing a force-multiplier that Doenitz had. Is there a short-circuit in my thinking?
Fair point and I stand corrected. The point I was trying to make was the ability to read and decipher the German codes was a massive advantage, but you are right, it removed a force multiplier.
Unless of course, your on one of the Milch Cows that got sunk
 
Fair point and I stand corrected. The point I was trying to make was the ability to read and decipher the German codes was a massive advantage, but you are right, it removed a force multiplier.
Unless of course, your on one of the Milch Cows that got sunk

Yeah, that could put a dent in one's day.

Your point was very clear and I believe apt, my little niggle aside.
 
Interesting the topic of how the UK prepared for war and the feeding of its population is very (to me anyway) interesting. The level of preparation was quite extraordinary but was still never sufficient to make us self sufficient, and that is the key point
The UK hasnt been self sufficient since the mid 1800s when the population exploded, hard to increase production when you are finding all sorts of jobs for all the men and women in the country.
 
Interesting the topic of how the UK prepared for war and the feeding of its population is very (to me anyway) interesting. The level of preparation was quite extraordinary but was still never sufficient to make us self sufficient, and that is the key point

The conundrum is that the more land one devotes to herding, the less is available for raising crops. The UK had something like 45 million people in that era on an island that, while productive, wasn't up to the task. And that requires proteins as well as greens and starches, so land-use can be an issue.

We Americans had the luxury of vast spaces in our Midwest that were productive. Putting those acres to use keeping the unsinkable carrier afloat was an important war aim for a reason: without the UK, it's hard to see a way for any American involvement that actually helps remove Naziism from Europe.

One of Churchill's phrases from his WWII memoirs I absolutely love is his notion of "invidious comparisons". They're worse than useless in wartime and should be avoided at all costs, between Allies.
 

Users who are viewing this thread

Back