"Bastard" Electro U-boats From Early 1943?

[T. A. Gardner]

So long as the Germans continued to rely on centralized control of their U-boats and required them to regularly communicate back to their HQ they were going to be hosed on this. The Germans did use burst transmissions. Didn't help. The Allies could still triangulate on the signals. The only way the Germans could have overcome this problem was to stop transmissions from the boats entirely.
Tactically, the Germans lacked a radios like the US TBS UHF system. This radio was almost line of sight making transmissions relatively secure between ships tactically simply by limiting the range the signal could travel.

On diving capabilities: This too really doesn't help that much. What the Allies discovered by the beginning of 1943 was that a u-boat that was submerged and being kept that way was almost as good a defense as actually sinking the boat itself. What the Allies resorted to in many cases wasn't spending the time to actually sink the boat but rather just drive it deep and keep it there.
For this purpose a single escort could stay behind and hound the u-boat for an hour or two then steam away and catch up with the convoy again. This would leave the u-boat a Hobson's choice. The only way to now catch the convoy was to surface and run on the surface to catch up. If the boat did this it was making itself highly vulnerable to attack. If the u-boat commander chose to run on snorkel or remain submerged the speed would be too low to regain an attack position so the convoy got away.
Since for the Allies the primary goal was the safe conduct of the convoy this worked just as well as sinking the boat. Plus, the pounding taken by depth charges and just the forced stay submerged wore on the boat crew and the boat itself.
With increasing numbers of escorts and aircraft the U-boat was looking at failure.

Now, another solution earlier in the war would have been to abandon the Type VII completely in favor of an enlarged Type XI that could have operated in more distant waters like off Africa or South America. The Germans would have had an advantage in expanding the area where ships needed convoying and escorts. This would have stretched Allied resources making it easier for all boats to attack shipping.

[Lars]

I agree fully that communications security would had been the easiest way to improve U-boatwaffe performance, like i wrote couple post a go.

In the end, as significant as radar was, its menace blinded Germans from grave deficiency of their radio procedures. Just blocking Ultra and shipborne HF/DF would had got U-boatwaffe going strong for several months longer in north-Atlantic, maybe even half year, with no other advancements in technology. It may had cost Allies the Normandy invasion during summer-44, and cost pennies for Germans. From latter part of -43 other measures are needed, as long range patrol ac, CVEs, and DEs become more and more abundant.

Deep diving was surely good defensive method, as it was very late in war till Allied got sonar equipment with any reliable depth measuring ability. Increasing the depth ability from, say around 100 metres that was about average on other navies submarines, to around 200 metres increased hugely the possible locations of submerged boat under attack - and gave them ability to go under convection layer (if present) in most of operating areas. Increased depth ability was good survival measure, but did not a bit increase offensive capability of boats.

Rewgards

Mark V,

I agree that blocking out Ultra and HF-DF could have postphoned the "Black May" of 1943, to, say, a "Black October" of 1943. But I´m curious as to how you propose to block Ultra and HF-DF out. The first requires a new and secure code, the latter scrambling of the HF-DF recievers or the scambling of the u-boats radio messages. Right up until the end of the war, the Germans never suspected that HF-DF was at work.

[T. A. Gardner]

Now, another possibility that could have had some positive value was Germany developing a torpedo with double or triple the range of their current ones. Given that they had some degree of working acoustic homing torpedo the Germans should have been able use that with a longer ranged torpedo to allow boats to fire from safer distances. Another possibility is a crude homing torpedo along the same lines using wire guidance by an operator. Maybe an HTP / alcohol torpedo or some other variant thereof?

[Lars]

The Germans were operating on an coding device which would have made HF-DF useless. its name was Kurier. It was a recorder which played off the U-boats short wave messages in a coded in form in under half a second. The British Amirality´s Operational Intelligence Center came 1944 to the conclusion that the fall out of HF DF would mean 30 - 50 % higher ship losses with 30 % as the most likely. Besides about a third less u-boats would be sunk. Had the Kurier been deployed in, say, early 1943, the loss ratio of ships per u-boat would have at least dobbelt. This could very well have given the u-boats ½ a year more before "a balck month". An interesting what-if indeed:

http://www.xs4all.nl/~aobauer/Kuriertact.pdf

[Mark V]

Tactically shipborne HF/DF was the best weapon on hands of Allied escort vessels in 1943. Countless contacts to enemy convoys were lost, runs to position ahead of convoy to initiate/continue attack the next night were frustrated... German were clueless, though they understood the basic vulnerability of their command and control system. U-boat commanders and Dönitz developed an awe of Allied airborne radar capability, because they thought it was the culprint for those long range interceptions.

Ultra did even more damage, but in less tangible way. Supply ships (and raiders) were destroyed fast in 1941 ***. Milk Cows were wiped from the sea couple years later. Many convoys mysteriously changed course and made dog legs, avoiding wolfpacks gathering in their route. When Dönitz sent his boats to south of Greenland, the convoys travelled across Atlantic in mid-latitudes, and vise versa.... For great many months of war Brits knew almost as much as Dönitz about current situation (fuel/torpedo levels, damages, wolf-packs) of U-bootwaffe at sea - almost in real time. Since mid-1943 when Allied had some escort vessels to spare, and CVEs, the Ultra gave them the areas to hunt - without Ultra, the active/free from escort duties, hunter killer groups would had been almost as useless as previous tries of ASW sweeps (ac was new dimension, but without Ultra - the Atlantic would had been still too large).

Block (or seriously curtail) these 2, and Allied would had had serious problems much longer. Of course Germans did not know about these breaches per se - though circumstantial evidence was mounting by 1943. U-boats in Atlantic had their own radio-grid, and Ultra could had been blocked by relatively simple measures, among small number of operators. Shipborne HF/DF was harder, but burst sending radio-equipment in U-boats would had come long way to limit its effectiveness (some other methods: self-destructing radio-buoys, UHF equipment for inter-wolfpack comms). These improvements does not need yard time, and fundamental changes to massive u-boat fleets boats itself.

Regards



*** Without Ultra, there is every prospect of successfull operations of surface supply ships (and raiders) in remote waters till late -42 or so. Roundup of all German surface assets from world Oceans from mid-41 to end of -41 was not because improved radar, increased number of Allied cruisers, better air cover....It was all about Ultra. Air cover for example in equatorial Atlantic did not fundamentally improve till turn of 1942/43, when Brazil, and somewhat later Azores, air bases did came available, and first CVEs were operating in mid-Atlantic. U-boats operating in Florida/Gulf of Mexico/Caribbean/Guyana/Brazil operations area, which was CRITICALLY important for Allies (almost all of their major vessels of blood did go through that area - oil, bauxite, copper, beef, coffee, timber, USN naval traffic from east to west coasts, etc. etc.), would had greatly benefitted from couple surface supply ships supporting U-boats and operating in Sargasso Sea, and near Brazilian coast during 1942. There were none available, as all were sunk by Ultra intercepts in 1941. In spring/summer 1942 U-boats that go to that area, shot their torpedo loads in couple days, and were desparate for more ammo and fuel to reap the fresh and plentifull harvest. Couple Milk Cows that were in service at that time did help Type VIIs to go there, but they could not help in ammunition shortage. Because of shortage of fuelling assets, the Type VII boats going to central-Americas operational area, drawled all through across Atlantic on 1 diesel engine, making around 9 knots (wasting precious time).

[Mark V]

With increasing numbers of escorts and aircraft the U-boat was looking at failure..

Talking in "what if" terms you are absolutely correct. If U-boats did not accomplish all-out victory by end of 1942, their eventual loss is assured by sheer power of US shipbuilding capability beginning to ramp up, but when ? May -43 is altogether different matter than November-43 for example, as everything that is planned to land in Europe must first be shipped across Atlantic.

Regards

[Lars]

Without Ultra, there is every prospect of successfull operations of surface supply ships (and raiders) in remote waters till late -42 or so. Roundup of all German surface assets from world Oceans from mid-41 to end of -41 was not because improved radar, increased number of Allied cruisers, better air cover....It was all about Ultra. Air cover for example in equatorial Atlantic did not fundamentally improve till turn of 1942/43, when Brazil, and somewhat later Azores, air bases did came available, and first CVEs were operating in mid-Atlantic. U-boats operating in Florida/Gulf of Mexico/Caribbean/Guyana/Brazil operations area, which was CRITICALLY important for Allies (almost all of their major vessels of blood did go through that area - oil, bauxite, copper, beef, coffee, timber, USN naval traffic from east to west coasts, etc. etc.), would had greatly benefitted from couple surface supply ships supporting U-boats and operating in Sargasso Sea, and near Brazilian coast during 1942. There were none available, as all were sunk by Ultra intercepts in 1941. In spring/summer 1942 U-boats that go to that area, shot their torpedo loads in couple days, and were desparate for more ammo and fuel to reap the fresh and plentifull harvest. Couple Milk Cows that were in service at that time did help Type VIIs to go there, but they could not help in ammunition shortage. Because of shortage of fuelling assets, the Type VII boats going to central-Americas operational area, drawled all through across Atlantic on 1 diesel engine, making around 9 knots (wasting precious time).

Mark V,

An interesting observation. This cuts right to core of the argument between Dönitz and Raeder. What was the best way to conduct naval war against Britain, was it u-boats as the only Schweerpunkt or was it a "balanced" strategy with fewer u-boats and more surface raiders?

Without Ultra the German surface raiders might have had a happy time in 1942 at the equator and the u-boats an even happier time than they had as supply boats with torpedoes and fuel would not have been sunk in 1941. Had it not been for Ultra, history would have looked much more kindly at Raeders "balanced" naval strategy and Britain would have been in for a true disaster in 1942.

[Lars]

So long as the Germans continued to rely on centralized control of their U-boats and required them to regularly communicate back to their HQ they were going to be hosed on this. The Germans did use burst transmissions. Didn't help. The Allies could still triangulate on the signals. The only way the Germans could have overcome this problem was to stop transmissions from the boats entirely.

I´m not sure this is correct. If you take the "Sonderschlüssel" (special key) which was introduced in late 1944 which gave each u-boat its own Enigma code and couple it with spurt transmissions like the Kurier (courier) process, I can´t see why centralized wolf pack tactics could not have continued.

The problem was that the Kurier only had 7 letters so it was probably an illusion to believe that the u-boats could communicate with Kurier only, especially in communication heavy environments like a running convoy battle. But solutions could probably be found. Have, say, a double Kurier machine and you have 14 letters. Then allow for pieced transmissions each with 14 letters. 3 sequenced transmissions and you have 42 letters.

[Mark V]

This cuts right to core of the argument between Dönitz and Raeder. What was the best way to conduct naval war against Britain, was it u-boats as the only Schweerpunkt or was it a "balanced" strategy with fewer u-boats and more surface raiders?

I don't want to go between herr admirals on this , but my viewpoint is that from Munich-38 onward - Germans should had concentrated fully to U-boatwaffe, surface fleet supporting the U-boats. As U-boats were after enemy tonnage, so should had the surface fleet with its limited resources. I am not too keen on BB/BCs doing commerce war though - they are fuel hogs, and Germans would always have extremely thin supply resources outside British blockade.

Support for U-boats would had ment blue sea operations of cruisers/panzershiffe, hilfskreuzer, fleet supply ships, but also lesser, covert supply ships (German fleet supply ships were extremely hard to camouflage and would stand out everywhere like sore thumb, as they were very large, top quality vessels - and that did show in their appearance). Some vessels stranded out of North Sea and anchoring in some neutral ports served later as supply ships and blockade runners, like some Allied vessels captured by raiders, but IMHO there was room for more organized small supply fleet, like half dozen or so small and fast fruit reefers equipped to supply U-boats. From 1943 onward Type XIV Milk Cows must stand in, and take the burden of supplying U-boats as surface assets can no more survive in Atlantic.

[Lars]

I don't want to go between herr admirals on this , but my viewpoint is that from Munich-38 onward - Germans should had concentrated fully to U-boatwaffe, surface fleet supporting the U-boats. As U-boats were after enemy tonnage, so should had the surface fleet with its limited resources. I am not too keen on BB/BCs doing commerce war though - they are fuel hogs, and Germans would always have extremely thin supply resources outside British blockade.

Support for U-boats would had ment blue sea operations of cruisers/panzershiffe, hilfskreuzer, fleet supply ships, but also lesser, covert supply ships (German fleet supply ships were extremely hard to camouflage and would stand out everywhere like sore thumb, as they were very large, top quality vessels - and that did show in their appearance). Some vessels stranded out of North Sea and anchoring in some neutral ports served later as supply ships and blockade runners, like some Allied vessels captured by raiders, but IMHO there was room for more organized small supply fleet, like half dozen or so small and fast fruit reefers equipped to supply U-boats. From 1943 onward Type XIV Milk Cows must stand in, and take the burden of supplying U-boats as surface assets can no more survive in Atlantic.

You are right that the surface raiders were fuel guzzling monsters. If Germany had build the Z-plan ships she wouldn´t have had the fuel for them. The fuel requirements were simply astronomical.

I have two comments to your mail though:

1/ What happens the invation of Norway if Germany swithces entirely to u-boat construction post-Munich?

2/ IMO, the Hilfskreuzers (auxiliary cruisers) was one of the great missed uppertunities for Germany. The few that did come into use were wildly succesfull. However, triple of quadrouple the number of auxiliary cruisers and the British should reinvent their q-ships projects from World War I, which were essentially the same as the Hilfskreuzers: Warships dressed up as civilian freighters. Still, more Hilfskreuzers should have been able to sink many more ships.

[Tim Smith]

Hilfskreuzers are no match for a real cruiser (surprise attack on Sydney excluded).

The Royal Navy had a LOT of cruisers.

[LWD]

...
2/ IMO, the Hilfskreuzers (auxiliary cruisers) was one of the great missed uppertunities for Germany. The few that did come into use were wildly succesfull. However, triple of quadrouple the number of auxiliary cruisers and the British should reinvent their q-ships projects from World War I, which were essentially the same as the Hilfskreuzers: Warships dressed up as civilian freighters. Still, more Hilfskreuzers should have been able to sink many more ships.

The British did have armed merchants in WWII. More Hilfskreuzers would probably have sunk more ships but how many more is a good question. If there were more of them out there they would be detected on a more frequent basis, more counter measures would be employed, and in general the opposition would be more alert.

Hilfskreuzers are no match for a real cruiser (surprise attack on Sydney excluded).

The Royal Navy had a LOT of cruisers.

And even then the Hilfskreuzer didn't survive the event.

[Mark V]

1/ What happens the invation of Norway if Germany swithces entirely to u-boat construction post-Munich?

Nothing much. Blucher would not be there as her building would had advanced at slower pace.

Still, more Hilfskreuzers should have been able to sink many more ships.

There is no room in world oceans for dozens camouflaged merchant raiders, but 3-4 or ships continuously in operating areas from autumn-39 till -42 would had used the opportunities there were much better than what Kriegsmarine accomplished historically. Dozen or so vessels altogether, and first ships would had to be clandestinily "put to refit after collision" before war started...

Add ten or so small, nondescript merchant ships equipped to support surface/U-boat assets. Maybe even couple sent as "Q-supply ships" to seas before war started (Germans used this method, but the vessels were ships surprised by outbreak of war, and were used later as supply vessels as an improvisation - they were poorly provisioned, equipped, and manned compared to dedicated supply vessels (fuel - preferably both diesel and heavy fuel oil, torpedoes, 20/88/105/150mm ammo, nonperishable food and good amount of frozen food, spares, equipment and personnel to do some basic repairs on power plants, good sized medical department, etc..)

Invasion of Poland was large enough operation that some basic preparations should had been made, in preparation that western powers would be worth their word to Poland. If not needed, Kriegsmarine would had still got some valuable experience in logistical operations in remote waters.

Regards

[Mark V]

more counter measures would be employed, and in general the opposition would be more alert.

Yep.

Every additional aircraft in southern waters would had been away from NW approaches of British Isles. Every cruiser sent there away from Mediterranean front or North-Atlantic blockade. Every additional AMC equipped consuming personnel resources, and away from troop carrying capability. Every convoy forced to be grouped taking around 20% away from maximum load carrying ability in given time, and spreading the already thin destroyer number to yet more tasks...

Isn't this exactly what Germans were after with Hilfskreuzer ?? - good sized disruption with minimal resources committed.

Regards

[Lars]

I´m reading Eberhard Rössler´s book about the type XXIII u-boat, the smaller cousin of the XXI. Two interesting facts. The first is that Rössler considers the British 1918 u-boat-hunter-submarine as really the first electro boat. The British submarine was designed to hunt German u-boats off the coast of Flanders. It´s top submerged speed of 15 kn was remarcable. Though the submarine did enter service before the war ended it never sunk any German u-boats. After the war it remained a top secret project and was largely forgotten.

The second interesting fact is that the book contains a small chapter on the Japanese electro submarines. Though the Japanese electro-boats came from a different conceptual angle than the German (active support of one´s own battleships instead of tonnage warfare), the Japanese build a quite advanced prototype in 1937 but could not make it fit into their naval warfare concept.