How effective were U-boats during WWII?

I was browsing through the internet and looking for info on U-boats. What I got from my search was, as much Allied tonnage sunk that were attributed to U-boats, it only represented 1% of Allied shipping where the U-boats operated. Is this true?

I just always thought that the amount of sunk tonnage was more significant than that. Forgive me for not providing a link to the site where I saw this info. from. History buffs, can someone please clarify?

[Tullaian]

Early in the war they were hugely succsessful sinking boats faster than Britain could make them and came close to turning the tide of the war. Churchill rated them the greatest threat to Britain's survival at one point in time. However as the war went on and America joined the war the uboats could no longer keep up with the massive increase in manufacturing availiable to the Allies and the % totals started to fall. By 1943 the ASW technology had the clear upper hand and tonnage totals started to fall dramatically.

In late 1942 the uboats were sinking in the order of 700,000+ tonnes of allied shipping a month , by the end of 1943 that had died to a trickle.

[Duli]

Originally Posted by Grifter808

I was browsing through the internet and looking for info on U-boats. What I got from my search was, as much Allied tonnage sunk that were attributed to U-boats, it only represented 1% of Allied shipping where the U-boats operated. Is this true?

I just always thought that the amount of sunk tonnage was more significant than that. Forgive me for not providing a link to the site where I saw this info. from. History buffs, can someone please clarify?

I think that this 1% thing is wrong.

Originally Posted by Duli

I think that this 1% thing is wrong.

I think so too.

[Laffertytig]

1941 was the darkest year for britain. when germany foolishly declared war on USA in dec41 that was the end. germany couldnt hope to compete with the industrial sizes of USA, UK and russia. in uboat terms there were just far to many ships being built and not enough uboats to sink them

[Curval]

Someone posted an article about Prien and it gives a detailed account of the U-Boat history in WW2.

Great article.

Found it:

http://www.u47.org/english/u47_kri.asp

[blueparrott]

In Clay Blair's "Hitler's U-boat war - The hunted 1942-1945" the there is a statistic mentioned. It deals with the period Sept -42 till May -45 and so does not include either of the so called "happy times", but still.

He claims that during this period 953 convoys comprising 43 526 ships sailed on the North and Mid Atlantic runs. 272 of these were sunk!! by u-boats (that is 0.6%)

He further claims that during the entire war there was 2919 ships sunk by u-boats. I havent been able to find any figure of total sailings, single or in convoy but the 1% sunk does not seem that unrealistic.

I know numbers cannot tell the entire story, but I still think the numbers are interesting and thought provoking.

[Nopileo]

Those of you who don't use SH3 Commander should give it a try. The information screen for each month throughout the war gives the stats of how much tonnage sunk versus how many subs lost.

For example, early war gives stats like '300,000 tons of shipping sunk for 2 u-boats lost', while later on it's more like '50,000 tons of shipping sunk for 25 u-boats lost'. It gives you an idea of what you can expect for the coming patrol...

[Shadow9216]

I highly recommend Blair's two-volume work. It's very detailed, and includes references from other, often-cited works, including German records, British and American archives, etc. It shows month by month, convoy by convoy, what the losses were. I'm not going to get into the details, as the book does a much better job of that.

More importantly, he goes into the mentality which prevailed at the time, and offers explanations for why things have been distorted, either minimizing or maximizing the actual impact.

The conclusions are surprising, but the facts are there, along with the original sources should anyone wish to examine the original documents.

The books in no way diminish the cost of the war, nor diminish the efforts on both sides. In some ways, a more objective look puts their efforts into perspective, and reveals a whole new respect for the crews of both sides.

[pampanito]

I completely agree. Blair's book is not taking anything for granted from previous secondary sources, and he just digs out the basic facts and figures.
Some of his conclusions had been suggested before by some authors, and dismissed by the 'official' historians. For example, any comment that Doenitz was perhaps not always correct in his decisions and grasp of situations is regarded by many as anathema. But probably Doenitz was tragically wrong when he viewed the submarine war as an attrition campaign, where the only important thing was to sink merchantmen, regardless of cargo, flag or destination. This Tonnage tactic was tantamount to declare war on the entire World merchant fleet and shipbuilding capacity (excluding of course Japan and Italy), a war that could simply not be won with the available U-boat force.
To send big type IXs to the South Atlantic or the Indian Ocean, in patrols taking up to three months, returning with just a couple of ships sunk, can only be viewed as a waste. To risk heavy losses while attacking westward-going convoys with mostly ships in ballast, was still worse. Churchill and other Allied leaders expressed only relief when U-boats were scoring considerable success off Freetown, off the Brazilian coast, on the Mozambique Channel, on the Arctic. To them, the only important theather was the North Atlantic and the life-line coming from America; the only thing that certainly made them shudder was that that lifeline would be cut, even if for a short time. For Germany it was a tragedy that whole U.S. armies and Air divisions were deployed to the UK almost without interference from U-boats in 1942/44. I hate to say this, but in this case Hitler was right in his strategic view of the U-boat war, he many times disagreed with Doenitz on the 'remote theathers' policy and was stubborn that all front-line boats should be deployed in the North Atlantic and only against traffic coming from the US (although he also gave in to the pressures from Italy and Rommel, and allowed many U-boats to be squandered in the Mediterranean).

Please excuse me for this long exposition, when I start I just can't stop! I'm possibly wrong in such a whole-hearted support of Clay Blair's ideas, but they are coincident with my own. I never understood what influence in the German war effort had the sinking of a ship carrying oranges from Southern Spain to Argentina, as was the real case.

[Gunfighter34]

You might also find the information in this paper interesting:

http://www.chinfo.navy.mil/navpalib/...campaigns.html

[Abraham]

I've once found some info, I don't know the source anymore, stating that one third of the U-boats never intercepted a convoy at all!
Since I have to rely on my memorie I'am not 100% sure (about 90%!), but Der Teddy Bär should know...

[Sarge McSarge]

It all depends on how you look at the stats.

In Clay Blair's "Hitler's U-boat war - The hunted 1942-1945" the there is a statistic mentioned. It deals with the period Sept -42 till May -45 and so does not include either of the so called "happy times", but still.

He claims that during this period 953 convoys comprising 43 526 ships sailed on the North and Mid Atlantic runs. 272 of these were sunk!! by u-boats (that is 0.6%)

He further claims that during the entire war there was 2919 ships sunk by u-boats. I havent been able to find any figure of total sailings, single or in convoy but the 1% sunk does not seem that unrealistic.

There was not 43,526 ships but 43,526 individual voyages. Was this 45 ships each doing every one of 953 convoys or 90 ships doing 476 convoys?? 272 does not look so bad when you look at it this way. If the sinking percentage was 1% per voyage then 10 voyages puts your odds up to 10%

A better way of looking at it is to look at the percentage of capacity sunk.
The total allied merchant shipping tonnage available in the Atlantic and Med was about 67 million tons. This includes about 38 million tons constructed during the war as well as what existed at the start. The U boats sunk about 14.5 million tons so it is closer to 25% of total and about half of what was available at the start of the war.

Sarge

[blueparrott]

[/quote]

There was not 43,526 ships but 43,526 individual voyages. Was this 45 ships each doing every one of 953 convoys or 90 ships doing 476 convoys?? 272 does not look so bad when you look at it this way. If the sinking percentage was 1% per voyage then 10 voyages puts your odds up to 10%

A better way of looking at it is to look at the percentage of capacity sunk.
The total allied merchant shipping tonnage available in the Atlantic and Med was about 67 million tons. This includes about 38 million tons constructed during the war as well as what existed at the start. The U boats sunk about 14.5 million tons so it is closer to 25% of total and about half of what was available at the start of the war.

Sarge[/quote]

Very good point (even though I am loath to admit it! :-))
Tonnage is an important aspect, especially if you consider it in a time frame. Tonnage lost in 1939 is unavailable for the entire war whereas tonnage lost in 1945. The figures of new construction also points to tonnage lost early in the war had a greater impact on total available tonnage than in the later years.
...and you can compare that with available u-boats to get a better grasp of effectiveness. All in all a complicated picture but very interesting.

I don't agree, though, that sinking westbound ship in ballast was a complete waste. Yes, it is more efficient to sink ship AND gargo, but a ship sunk is one less ship to carry cargo next time.

[Abraham]

But remember that the cargo is often more expensive than the carrier (the ship)!

To complicate things further you have to look at the resources used to maintain the sub campaign from the German side and the resources needed from the Allied side to beat it.

I think the U-boat campaign was from a material (not human!) point of view a cost-effective way of waging war and the only means that could perhaps have brought Britain on its knees, if there had been a concentrated effort from the German side.
But the Germans never had proper support from the Luftwaffe, neither with long range patrols over the Atlantic with Condors nor with air defence above the Bay of Bisqai...

The Battle of the Atlantic was won in the air, by the Allies.