Disaster at Narvik: Gunter Prien's torpedoes work

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Deleted member 1487

http://uboat.net/articles/?article=23

When the British Expeditionary Force (BEF) finally set out for Narvik on April 15th, Naval High Command and BdU had a difference of opinions as to where exactly the British will disembark. High Command considered the fjords Lavangen and Gratengen to the north of Narvik most probable. Dönitz, however, believed that the site of disembarkation would be Bygdenfjord, also to the north of Narvik, but at a greater distance. Consequently, he was proven right when late on April 15 Gunther Prien of U-47 arrived at Bydgenfjord and spotted three large British transports (some 30,000 GRT each) and several smaller ones disembarking troops in fishing boats. Immediately the Raging Bull fired 8 torpedoes with impact pistols at the stationary and overlapping targets, but all of them missed. This could have been a major disaster for the BEF and a valuable help for the outnumbered mountain troops defending Narvik.

These failed because of a manufacturing defect that caused the torpedoes to run too deep, causing them to miss. What if these 8 torpedoes hit their mark? It would mean over 100k GRT of shipping gone in a matter of minutes, the loss of thousands of British troops, and a dislocation of the Allied effort around Narvik.
What happens then during the Norwegian campaign? Does it provoke the British to reassess their naval doctrine? What about the Germans and the torpedo crisis? Do they still tackle the issue around the same time?
 
http://uboat.net/articles/?article=23



These failed because of a manufacturing defect that caused the torpedoes to run too deep, causing them to miss. What if these 8 torpedoes hit their mark? It would mean over 100k GRT of shipping gone in a matter of minutes, the loss of thousands of British troops, and a dislocation of the Allied effort around Narvik.
What happens then during the Norwegian campaign? Does it provoke the British to reassess their naval doctrine? What about the Germans and the torpedo crisis? Do they still tackle the issue around the same time?

There is a definate mistake in your source there, there were no merchant ships that big at Narvik!
 
Besides 100% hit rate?!
Then again even a plausible average for the time (say 2 or 3 out of 8) could still have done a lot of damage right?
 

Deleted member 1487

There is a definate mistake in your source there, there were no merchant ships that big at Narvik!

No merchant ships, but what about military transports?

Besides 100% hit rate?!
Then again even a plausible average for the time (say 2 or 3 out of 8) could still have done a lot of damage right?

http://forum.axishistory.com/viewtopic.php?t=70786&start=0
16 April 1940
U-47 (Type VIIB) attacks 4 troop transports at anchor in Bygdenfjord. Range 750-1500 yds. Ships in a solid wall ahead of U-boat. Fired 4 torpedoes from periscope depth at 22:42 hours. Result nil - all torpedoes failed to explode. Enemy not alerted. Reloaded. All torpedoes thorughly checked. Surfaced after midnight and attacked again. Precise fire control data - torpedo running depth set at 12-15 feet. 4 more torpedoes fired. Result nil. 1 torpedo off course, exploded against the cliff. Enemy alerted - U-47 withdraws. Runs aground, refloated. Pursued with depth charges - engines damaged. Escaped. Summary: 8 torpedoes fired at stationary targets at close range, and no hits.

Apparently the shots were at extremely close range on stationary targets. Its not hard to imagine a 100% hit rate. But there wouldn't be as many torpedoes, because there were two separate attempts hours apart.
 

BlondieBC

Banned
In OTL, Hitler wanted to retreat from Narvik, but Jodl persuaded him not to retreat using the argument that if one kept fighting hard, even when badly supplied, often good things happen. So an easy Nazi victory at Narvik might butterfly away Stalingrad, i.e. Hitler might allow a retreat.

My source is a tv show on the history channel, but if true about Narvik, it was an important turning point in how Hitler though about retreating.
 
http://uboat.net/articles/?article=23



These failed because of a manufacturing defect that caused the torpedoes to run too deep, causing them to miss. What if these 8 torpedoes hit their mark? It would mean over 100k GRT of shipping gone in a matter of minutes, the loss of thousands of British troops, and a dislocation of the Allied effort around Narvik.
What happens then during the Norwegian campaign? Does it provoke the British to reassess their naval doctrine? What about the Germans and the torpedo crisis? Do they still tackle the issue around the same time?

The torpedoes worked fine when tested - in the Baltic. Unfortunately for Prien and other U-boat skippers the Baltic is much saltier than the Atlantic, so torpedoes run deeper in the Atlantic than the Baltic and no one bothered to test any in the Atlantic.

The result was an understandably irate Prien complaining that he'd been sent out to fight with wooden guns and a thorough housecleaning of the Kriegsmarine's torpedo design bureau, followed by a redesign of the torpedoes, which gave no further trouble.

Assuming the torpedoes work properly, Prien would probably have sunk and/or damaged two or three transports, which would certainly have scuppered British plans for an amphibious landing. The troops would probably have suffered few casualties, but they would have lost most of their equipment, vehicles, and supplies, which would have considerably handicapped them. At that point they would probably have aborted their landing and left the Germans in possession of Narvik. In other words, much the same result as OTL, just a little sooner.
 
If the first salvo detonated, then there would never be the second one. Herr Prien would have to get the hell out of dodge city ASAP.
 
IIRC, the Germans concluded after that there had been 20 certain hits against battleships, cruisers, destroyers and transports that didn't go bang...how they concluded this i'm not sure.
 
It's worth noting here that our submariners had the same problem with the Mk XIV torpedoes when they were first introduced; they worked fine when fired at right angles against stationary targets in the Atlantic, but in the warmer and therefore less dense Pacific they ran deeper than set (as much as twenty feet deeper) and if they struck the target at an angle, which was almost always the case, they usually failed to detonate.

The problem was made worse by the refusal of the design bureau to accept that their test procedures were inadequate or that the torpedoes were defective; they insisted that the submariners were at fault. It took the intervention of Admiral King himself to get them to fix the problem.
 

Deleted member 1487

It's worth noting here that our submariners had the same problem with the Mk XIV torpedoes when they were first introduced; they worked fine when fired at right angles against stationary targets in the Atlantic, but in the warmer and therefore less dense Pacific they ran deeper than set (as much as twenty feet deeper) and if they struck the target at an angle, which was almost always the case, they usually failed to detonate.

The problem was made worse by the refusal of the design bureau to accept that their test procedures were inadequate or that the torpedoes were defective; they insisted that the submariners were at fault. It took the intervention of Admiral King himself to get them to fix the problem.

There was also a manufacturing defect in German torpedoes that allowed the airtight internal works to leak, meaning they took on air that ended up upsetting the mechanism that determined depth. It wasn't just design, but poor quality control.
 
It's worth noting here that our submariners had the same problem with the Mk XIV torpedoes when they were first introduced; they worked fine when fired at right angles against stationary targets in the Atlantic, but in the warmer and therefore less dense Pacific they ran deeper than set (as much as twenty feet deeper) and if they struck the target at an angle, which was almost always the case, they usually failed to detonate.

Didn't the Germans steal the American torpedo design, with the defective settings?

As to the OP, once the initial problem was recognized (Baltic is saltier, so torps will run deeper in Atlantic), why didn't the German skippers set their torps to a shallower depth until proper replacements arrived? Unless it would have led to the torpedos porpoising on the way to the target?

(torpedo porpoising - some torpedos required a minimum amount of water over them to provide proper pressure. If they didn't have that much water, they would travel up until they broke the surface, then pop back down again. So the torpedo pops up and down in the water, and has a ~50-50 chance hitting above or below the waterline.)
 

Deleted member 1487

Didn't the Germans steal the American torpedo design, with the defective settings?

As to the OP, once the initial problem was recognized (Baltic is saltier, so torps will run deeper in Atlantic), why didn't the German skippers set their torps to a shallower depth until proper replacements arrived? Unless it would have led to the torpedos porpoising on the way to the target?

(torpedo porpoising - some torpedos required a minimum amount of water over them to provide proper pressure. If they didn't have that much water, they would travel up until they broke the surface, then pop back down again. So the torpedo pops up and down in the water, and has a ~50-50 chance hitting above or below the waterline.)

Not that I've ever read and I've read a lot of WW2 books. They did steal the Norton bomb sight and it worked just fine.
 
Not that I've ever read and I've read a lot of WW2 books. They did steal the Norton bomb sight and it worked just fine.

Correct. Two entirely separate (if similar) screwups.

As for the Germans correcting their depth settings, that is precisely what they did do once they realized what was happening. Of course if the torpedoes had been properly tested they would have been correctly set to begin with ...
 
IIRC, the Germans concluded after that there had been 20 certain hits against battleships, cruisers, destroyers and transports that didn't go bang...how they concluded this i'm not sure.

Simple: Prien wasn't the only U-boat skipper affected by the faulty torpedoes; several others reported similar problems.
 
As to the OP, once the initial problem was recognized (Baltic is saltier, so torps will run deeper in Atlantic), why didn't the German skippers set their torps to a shallower depth until proper replacements arrived? Unless it would have led to the torpedos porpoising on the way to the target?
Oops. The Baltic is fresher. It has lots of fresh water coming in and little evaporation.
 
Simple: Prien wasn't the only U-boat skipper affected by the faulty torpedoes; several others reported similar problems.

U-39 fired 3 fish at ark royal in 1939 1, of which blew a 21 inch hole in the rudder, but didn't detonate; and the other 2 prematurely detonated; giving away the U-boats position at which time she was depth charged by escorts
 
Oops. The Baltic is fresher. It has lots of fresh water coming in and little evaporation.

Mea culpa; I had it backwards. The fact remains, though, that the torpedoes were not tested under the conditions they would be used in, and no one thought about the effects of water temperature and salinity on water density and depth settings.
 
The Germans also had problems with their magnetic detonators functioning correctly. In areas of high magnetic field strength they had a bad habit of going off too soon. This despite being warned there was a possible problem in the 1930's.

Lots of examples of such problems can be found all over the place and in all nations. The Demon Murphy has vast power.

Michael
 
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