Was the Elektroboat really a "wonder weapon"?

[davebender]

The Type XXI submarine was a great advance over 1930s designs but it was not invulnerable.

By 1945 there were so many Allied DEs and ASW aircraft that no enemy submarine could operate effectively in the North Atlantic. How could they when Germany couldn't even maintain air superiority over submarine bases and the surrounding coastal waters?

 

[barney]

If you wish to see the American version of the XXIII here is the link.

USS MARLIN

I had occasion to visit this vessel when first on display in Omaha. What a blast. I found that the boat's blueprints and operating manuals were still in lockers in the wardroom. Back toward the stern, the aisles around machinery were were tiled and they were one tile wide - back when they made 9 inch floor tiles. Everything still worked so you had to be careful to not elbow switches.

It is funny to think that nobody seemed to realize that the upper half of a submarine needed to be streamlined like the hull until they finally did. But then I remember viewing the Marlin, perched as she was out of the water and there, in the middle of each prop blade was a Navy applied zinc brick about the size of a cinder block. What did that do for performance?

 

[Matt308]

Gentlemen, please keep this thread civil, tone it down and do not levy veiled insults to other members. You will not be warned twice.

 

[davebender]

Probably part of the cathodic protection system used by ships in mothballs.

 

[barney]

Probably part of the cathodic protection system used by ships in mothballs.

Yeah, that makes perfect sense.

 

[psteel]

Prior to WW-I a German air independent propulsion system was experimented with that looked promising, but the war prevented further development. The British did have a high underwater WW-I sub able to make 14 kts submerged for about 15nm endurance ….again good, but somewhat limited tactically.

British R class submarine - Wikipedia, the free encyclopedia

The German Type XXIII apparently went on a few cruises with new crews and were able to sink 5-6 merchants without any losses, when the yearly average was about two subs for every merchant sunk.

looking at this site we have pre war Go-71 which could make 21knts underwater but only had endurance of 30nm @ 7knts. So it could not really use its dash speed realistically.

71-go experimental submarine (1938) - Imperial Japanese Navy (Japan)

About the same time the Germans were working on the Walters V-80 experimental fish submarine. This was tested [100 sortie] and made 50nm@ 28knts.Given that the best the service subs could make was 80-60nm@ 4knts and about 15nm @7kts; one can see the potential, but to be fair that was Walters infamous peroxide drive turbines. It's not just a high underwater speed, but high endurance that's part of the evolution of the threat from 'submersibles' into 'genuine submarines'. Dr Walters who designed the boat in the mid 1930s, also included a complicated retractable Schnorkel system. Weaponizing this into the V-300 and follow on designs during wartime; proved to be much more difficult due to the politics of Hitler's armaments programs , but did result in 200 additional sortie with only one accident incident leading to one death. The system seemed to be robust enough to work in put into mass production.

When the process closed in on the Type XVIII Walter design, the amount of fuel per sortie [~ 200tons] would be an enormous challenge to overcome, since annual production was merely 12000 tons and the missile programs took the bulk of that. German naval designers pointed out that the space eked out for the Peroxide fuel, was more than enough room to triple the battery capacity increasing potential from 80-60 nm to 220-180nm@ 4 knots. New more powerful creep motors were designed that allowed underwater endurance to increase to 300-225nm @ 5kts.

Furthermore new HP generators were nearly completion that could effectively triple the power to weight ratio of these Submersibles. Given existing Submersible design; that should lead to a top underwater speed of ~11-12 knots. As it was submersibles designs relied on large flooding slits in the hull to allow rapid crash dives of 30-40 seconds. In WW-I before these appeared, the crash diving took up to 2 minutes, but there was a draw back since it reduced top underwater speed by about 10-12%. If on the other hand the sub was to remain mostly underwater using Schnorkel these numerous flooding slits were not needed and increased top speed could be achieved brining that to 13 kts. Further the "Winter garden" explosion of railings and flak guns the Germans added along with inefficient conning tower design added at least one knot to the top speed [14kts]. The rest of the increase to speed to ~ 18knts for the Type XXI was in the actual streamlining of that submarine design.

At this time some German leaders pointed out that many of these same ideas could be back fitted to the existing fleet of 400-500 Type VII/IX submersibles. Tripling the battery power sealing up the flooding slits, should allow the top underwater speed . Historically this would have delayed the XXI/XXIII program by months and this was considered unacceptable. But in truth all this could have been done 1942-44 transforming the 'Submersible fleet' into a 'submarine fleet'.

The initiative to add the Flak "winter gardens" could have instead been used to adopt a small streamlined weaponless conning tower with a tractable Schnorkel and clear out the internal ammo plus 4 reserve torpedoes to make space for the triple battery capacity.Combined this would have allowed these subs to reach ~11 knots submerged [Type XXIII reached 12knots] with an endurance of about 180nm@4 knots [Type XXIII could reach 175nm @ 4knts].

 

[davebender]

For some reason the German Navy was slow to adopt this device. In fact at least one Dutch submarine captured during 1940 had the Schnorkel removed before being placed into German service.

 

[psteel]

From an operational point of view the wolfpack had to work on surface to hunt for enemy shipping since the LW failed to integrate into operations. Even schnorkeling reduces radius to 3/4 of the surface endurance and makes actual detection alot harder. That is until the GHG gets developed and allied airpower forces the Germans below the water. Trouble is this was all forseen before the war began. The recommended solution was to make better use the LW in an integrated strategy, but Adm Dontiz solution was instead to rigg the Uboats to out fight the allied airpower and install some ultra light gyro copters for extended vision. Standing and fighting in enemy airsuperiorty was a poor second choice to exploiting the best quality of UBoat, to disappear below the surface.

 

[davebender]

I agree. That's not what snorkels are for.

Snorkels allow a submarine to transit to their patrol area in relative safety. Expecially important in the Bay of Biscay as you are almost immune to dectection by WWII era aircraft. Snorkels also allow you to recharge batteries in relative safety before resuming attacks on enemy shipping.

 

[delcyros]

If I can offer my 2 cents worth thinking on the subject...

The XXI wasn´t the first high underwater performing submarine. The ROYAL NAVY R-class submarines of 1918 vintage had very comparable performances at least on the paper.

The XXI (and XXIII) suffered some issues, which is true, too.
You may name f.e.
[+] poor workmanship compared to earlier boats. Some had to underwent repairs to be servicable and capable of diving
[+] the Walter 8 hullform was untried and is statically difficult to calculate. They made design mistakes here. That is crush depth has been varied between 280m and 305m in british and US trials, that was somehow less than earlier type VIIc/41 boats and somehow short of design expectations
[+] initial design speed was 18.0 kts submerged at the one hour rating. However, such a speed was found to be impossible. The batteries could not produce the high currents required to max out the electric motors. At full current, the power delivered by the batteries dropped and max power was unattainable. A change of the flooding slits increased the hydrodynamic drag but a compromis between diving time and top speed eventually was found. Realistic top speed was slightly faster than 16 kts (17.1 kts if You accept longer diving times) and the endurance was 1.20 hours instead of the intended 1.40 hours at this rating.
[+] The boat was silent by period standarts but the offensive firecontroll wasn´t yet fully developed to the high underwater speed. Designers of the GHG weren´t informed about XXI´s speed capabilities and correspondingly, the GHG passive detection arrey initially had problems at any speed faster than 8 kts and quit working at speeds faster than 11kts. A change in fairing over the GHG balcony was required to fix the issue after which the GHG worked out to 15.5 kts in trials. This happened in february 1945 and at wars end not all XXI were yet modified to the new standart
[+] Readers familar with the XXI perhaps know that the boat had been designed with excess battery reserve capacities. However, the recharging took considerable time. To the first battery stage (60% level) it took 2.6 hours, then 2.5 hours more to the 90% level and a last 2.4 hours to the 100%. However, this is at best conditions, in normal conditions when snorting, the recharging to 6.2 hours to the 90% level.
[+] There were considerable problems with H2 generation by the batteries, creating a dagerous gas mixture. The H2 vents and filters didn´t statisfied and at least two serious accidents are reported with XXI H2 explosions in post war services.

--------------
Despite these limitations, the XXI was a highly developed underwater attack platform. The much improved GUPPY refits of USN fleet boats in the period 1946 to 1954 had comparable top speed performance (up to 16 kts) but despite battery enlargements and improved battery types, the speed could only be hold for 30 minutes as compared to 1 hour and 20 minutes in type XXI. The GUPPY´s also were much noisier than U-2513 and U-3008 trialed by the USN off Key West after the war. The GUPPY´s also neither enjoied a passive acoustic detection arrey, nor the much superior S(U) active / passive sonar device of XXI (later adopted to USN services). Also, they had to be at periscope depth to fire a torpedo and fielded no homing or pattern running torpedoes. Still, in trials against DE´s with 1948 ASDIC equipment, GUPPY´s had a chance to avoid beeing damaged by a hunter group of 5 DE which varied between 70 and 85% after contact. Agressively handled, a GUPPY once torpedoed all five DE and then engaged the protected convoi in these trials. These trials were very alarming but little could be done at this point. If the submarine increased speed to 12 kts or faster the success rate of the 5 DE dropped suddenly to 0% in all trials. GUPPY´s could be heard at speeds faster than 5 kts, though U-2513 couldn´t be detected even from a stationary HE listening platform moving at max speed of the creep motors (6.2 kts), at 16 kts top speed it was as noisy as a GUPPY at 11 kts and at 10 kts it was barely detectable at best conditions with a 10 kts moving platform and close range. ASDIC wasn´t effective at depth´s larger than 400ft and it´s range varied with conditions between 800 and 1500 yard. The mk24 FIDO homing torpedo/mine didn´t worked at depths larger than 300ft maximum diving depth and with 12 kts top speed hadn´t the required speed to effectively hunt down such a fast submarine.
The first submarine type which approached XXI performance after end of ww2 was the US TANG-class after the troublesome radial 8 zylinder pancake diesels were removed by normal 6 cylinder Diesel units in 1952.

 

[Milosh]

If anyone is interested,

 

[davebender]

Many things constructed in 1945 Germany were poor quality. How could it be otherwise? Component manufacturers were destroyed by bombing or over run by enemy ground forces. So late war German equipment was bound to include a multitude of substandard components that wouldn't meet normal safety standards.

 

[delcyros]

That´s correct, Dave.

Still, it needs to be outlined. The XXI was demanding in mastering all the advanced technologies implemented. That means a lot of issues to work out and additional training for crews to complete the tactical courses, the principal reason why so few boats were attached to flotilla 11 in Bergen/Norway at wars end.
Initially, the XXI was intended to carry a close range SUBROC defensive missiles in it´s stern compartement. Altough the weapons and it´s targeting device were developed and tested, mass production didn´t stated and the compartement was shipped empty in all operational boats.
Similarely, the torpedo tubes were of a new design and could have allowed wire guided and active homing torpedoes ("Lerche" in german torpedo terminology) and shots from a depth of up to 100m (OT-II). Though neither the Lerche nor OT-II was operational and these boats carried pattern running LuT and OT-I which was servicable down to 40/50m.

This platform, despite it´s numerous limitations was advanced but it could not have stopped the soviets from advancing into Germany. So it´s not what the period propaganda made out of it.

 

[psteel]

Delcros this is very interesting information and I would like to read more on the subject of the Guppy and the post war sources. Can you share with us your sources on these matters?

If I can offer my 2 cents worth thinking on the subject...

The XXI wasn´t the first high underwater performing submarine. The ROYAL NAVY R-class submarines of 1918 vintage had very comparable performances at least on the paper.

The XXI (and XXIII) suffered some issues, which is true, too.
You may name f.e.
[+] poor workmanship compared to earlier boats. Some had to underwent repairs to be servicable and capable of diving
[+] the Walter 8 hullform was untried and is statically difficult to calculate. They made design mistakes here. That is crush depth has been varied between 280m and 305m in british and US trials, that was somehow less than earlier type VIIc/41 boats and somehow short of design expectations
[+] initial design speed was 18.0 kts submerged at the one hour rating. However, such a speed was found to be impossible. The batteries could not produce the high currents required to max out the electric motors. At full current, the power delivered by the batteries dropped and max power was unattainable. A change of the flooding slits increased the hydrodynamic drag but a compromis between diving time and top speed eventually was found. Realistic top speed was slightly faster than 16 kts (17.1 kts if You accept longer diving times) and the endurance was 1.20 hours instead of the intended 1.40 hours at this rating.
[+] The boat was silent by period standarts but the offensive firecontroll wasn´t yet fully developed to the high underwater speed. Designers of the GHG weren´t informed about XXI´s speed capabilities and correspondingly, the GHG passive detection arrey initially had problems at any speed faster than 8 kts and quit working at speeds faster than 11kts. A change in fairing over the GHG balcony was required to fix the issue after which the GHG worked out to 15.5 kts in trials. This happened in february 1945 and at wars end not all XXI were yet modified to the new standart
[+] Readers familar with the XXI perhaps know that the boat had been designed with excess battery reserve capacities. However, the recharging took considerable time. To the first battery stage (60% level) it took 2.6 hours, then 2.5 hours more to the 90% level and a last 2.4 hours to the 100%. However, this is at best conditions, in normal conditions when snorting, the recharging to 6.2 hours to the 90% level.
[+] There were considerable problems with H2 generation by the batteries, creating a dagerous gas mixture. The H2 vents and filters didn´t statisfied and at least two serious accidents are reported with XXI H2 explosions in post war services.

--------------
Despite these limitations, the XXI was a highly developed underwater attack platform. The much improved GUPPY refits of USN fleet boats in the period 1946 to 1954 had comparable top speed performance (up to 16 kts) but despite battery enlargements and improved battery types, the speed could only be hold for 30 minutes as compared to 1 hour and 20 minutes in type XXI. The GUPPY´s also were much noisier than U-2513 and U-3008 trialed by the USN off Key West after the war. The GUPPY´s also neither enjoied a passive acoustic detection arrey, nor the much superior S(U) active / passive sonar device of XXI (later adopted to USN services). Also, they had to be at periscope depth to fire a torpedo and fielded no homing or pattern running torpedoes. Still, in trials against DE´s with 1948 ASDIC equipment, GUPPY´s had a chance to avoid beeing damaged by a hunter group of 5 DE which varied between 70 and 85% after contact. Agressively handled, a GUPPY once torpedoed all five DE and then engaged the protected convoi in these trials. These trials were very alarming but little could be done at this point. If the submarine increased speed to 12 kts or faster the success rate of the 5 DE dropped suddenly to 0% in all trials. GUPPY´s could be heard at speeds faster than 5 kts, though U-2513 couldn´t be detected even from a stationary HE listening platform moving at max speed of the creep motors (6.2 kts), at 16 kts top speed it was as noisy as a GUPPY at 11 kts and at 10 kts it was barely detectable at best conditions with a 10 kts moving platform and close range. ASDIC wasn´t effective at depth´s larger than 400ft and it´s range varied with conditions between 800 and 1500 yard. The mk24 FIDO homing torpedo/mine didn´t worked at depths larger than 300ft maximum diving depth and with 12 kts top speed hadn´t the required speed to effectively hunt down such a fast submarine.
The first submarine type which approached XXI performance after end of ww2 was the US TANG-class after the troublesome radial 8 zylinder pancake diesels were removed by normal 6 cylinder Diesel units in 1952.

 

[delcyros]

Psteel,

You may consider
J. Roberts article about Guppy conversions interesting in that matter, published in Warship International 1989. It´s interesting but a bit aged now.
I also relied heavily on
Palmer, Origins of the Maritime Strategy: The Development of American Naval Strategy, 1945-1955 (Washington 1988);
Polmar/Moore, Cold War Submarines: The Design and Construction of U.S. and Soviet Submarines (Washington 2004);
Denny, Blip, Ping Buzz: Making Sense of Radar and Sonar (Baltimore 2007);
Friedman, U.S. Submarines Since 1945: An Illustrated Design History (Annapolis 1994);
Friedman, British Destroyers Frigates: The Second World War and After (London 2006);
Friedman, U.S. Destroyers: An Illustrated Design History (Annapolis 2004);
Harding, The Royal Navy, 1930-2000: Innovation and Defence (Abingdon 2005);
O´Brian, Technology and Naval Combat in the Twentieth Century and Beyond (London 2001);
O´Connel, Submarine Operational Effectiveness in the 20th Century: 1939 - 1945 (Bloomington 2011);
Rössler, U-Boottyp XXI. 7th Ed., Bernard Graefe Verlag (Bonn 2005);
Rössler, Die Sonaranlagen der deutschen U-Boote. (Bonn 2006)

Friedman and Harding, along with Polmar/Moore are extremely important sources published recently.

Harding (p.150ff) goes into some details as with regard to sequential trials conducted 1948 to 1949 off Key West with GUPPY modified USS TRUMPETFISH and the 4th EF as a preparation followed by tactical trials with USS AMBERJECK and the 6th DF in summer 1948, followed by trials with USS SCOTSMAN and USS DOGFISH november´48 to march 1949. During the last trials the 6th DF was enforced by two more DE´s, BROADSOWRD and SCORPION.
These trials were triggered by examination and trials of U-2513 and U-3008 off Key West, which caused some excitement in US submariner circles (eventually leading to the US submariners rejection of BuShip´s proposal for a US postwar submarine 1946) but also raised questions as to ASW efforts necessary to overwhelm these fast types of submarines.

At least in one case USS TRUMPETFISH aggressively handled would have sunk all four DE´s and proceeded further to the convoi. Probability to achieve a damage with type 144 ASDIC and Squid ranged between 13.0% (mean against USS SCOTSMAN) and 32.3% (USS DOGFISH) but the trials were kind of skewed for peacetime (in wartime the submarines would fire anti escort homing torpedoes, which the escorts didn´t minded here). It was also questioned whether or not four to six escort vessels would be aviable at any time to deal with a single fast submarine. Also, it was pointed out, that the probability to achieve a damage suddenly dropped to 0% in all trials when the submarine increased speed to 12 kts or faster or slower than 4 kts.

 

[psteel]

Hi Delcryos


Just so I'm getting this clear, your recommending these following titles to explore the trails mentioned in the previous posts?

Harding; The Royal Navy 1930-2000 (Naval Policy and History)
Polmar/Moore, Cold War Submarines: The Design and Construction of U.S. and Soviet Submarines (Washington 2004);
Friedman, U.S. Submarines Since 1945: An Illustrated Design History (Annapolis 1994);

Is that right?


hummm I can get "Palmer, Origins of the Maritime Strategy: The Development of American Naval Strategy, 1945-1955" at the library.
Also; Cold War submarines : the design and construction of U.S. and Soviet submarines / Norman Polmar and Kenneth J. Moore.


btw you wrote...

Also, it was pointed out, that the probability to achieve a damage suddenly dropped to 0% in all trials when the submarine increased speed to 12 kts or faster or slower than 4 kts.

This is refering to the chance the ASW weapon has on the Sub at those speeds?

 

[parsifal]

havent read all the posts guys, so my apologies in advance.

Type XXI were a generational change in sub techs, and casualty rates would have dropped substantially if introduced in 1945 and the fighting continued in that year. Moreover offensively the high speed endurance and torpedo auto loading system would have made them very dangerous. I have also read the hull was coated in a rubber like compound to reduce sonar effectiveness, and the engines designed for better silent running. They still emitted quite a bit of noise at 10 knots+ but less than the 1930s clunkers equipping the KM at that time.

With all those advantages there would bound to be some improvement in submarine operations for the germans, but the allied countermeasures, numbers and training would still win the day in my opinion. We trained with subs at least as good as tghe Type 21s and had no difficulty in tracking them down and sinking them (well, in simulation at least) on a more or less regular basis. The key to defating them were carriers....lots of them, and the US was building or had built 140 of them by 1945, whilst the Brits were completing a further 20 or so "trade protection carriers"...colossus class etc, in 1945. The western approaches would have been a very busy and hectic place in 1945, and I have serious doubts that the type XXis could have made much of a dent against that level of defence.

 

[delcyros]

btw you wrote...



This is refering to the chance the ASW weapon has on the Sub at those speeds?

No, it´s a function of attaining a fix on the boat in the first place. If the GUPPY went slower than 4 kts it was practically not discriminable by background noises by methods of HE. If it went faster than 12 kts, the ASDIC gear failed, or, in case another DE went slower and forwarded the ASDIC data by wireless to the faster hunter ship, the probable error was larger than 400 yard with type 144 ASDIC.

A GUPPY is not quite a XXI but it represents a reasonable match.

We trained with subs at least as good as tghe Type 21s and had no difficulty in tracking them down and sinking them (well, in simulation at least) on a more or less regular basis.

Would You mind to share Your experiences Parsifal?

thanks in advance,
delc

 

[parsifal]

Would You mind to share Your experiences Parsifal?

I participated in naval excercises known as RIMPAC in the late 70s and early 80s (ther were also some other excercises, including training with the five power defence pact). I served on the carrier and the DDG HMAS Brisbane.

Airpower back then was critical to the ASW counterstrategy. We used Grumman Trackers for distant early warning and Wessex and Sea King Choppers for detection close in. We used Barra Sonar bouys and the mulloka sonars. Principal weapons were the homing torpedoes and the Ikara launch sytem, which had an effective range of 10NM, until the arrival of the NCDS which effectively doubled that range, because the missile could be guided onto the target using the fixes obtained by the heos dropping the dunking sonars. An ASW detachment could vary in size, but a ty[ical detachment might be 3 Frigates and 2 or 3 helos and about the same numbers of fixed wing A/C.

We exercised with both nuclear attack subs and conventional diesel electrics. The most dangerous were by far the Oberon class when fitted with Harpoon sub launched anti shipping missiles (which unfortunately were only ever simulated....we never fif get those misiles) or Mark 48 wire guided torpedoes (which they did get, and became deadly with). Oberons were slow, but they were extremely quiet, and had this very nasty habit of being able to use ocean thermocline and salinity layers to get into position undetected. If they were equipped with Mk 46 torps, the nearest equivalent to the armament that was carried by a Type XXI they had no hope against the modern ASW defences that we could breeing to bear. Even our ancient Darings, by then using Limbo mortars and WWII era sonars could hunt them down and "sink" an Oberon, if it had assistance from airborne assets.

SSBN and SSN subs were much faster, but were noisy. They were expensive, so were seldom used for shipping attacks, but because of their noisy characteristics we could generally take steps to deal with them. Because of their speed, it was usually best to attack them from the air rather than try and run them down with ships.

Even 1970s sonars still had problemes performing well at high speed. Before NCDS we would usually have two relatively slow moving ship[s undertaking the search patterns, assisted by aircraft , and one attacker. After NCDS all threee DDs would undertake the attacks....they could use the helos detection system to guide their weapons onto the target.

Subs in 1945 against a well defended convoy with good aircover needed effective standoff weaponary. I am not aware that the KM possessed that capability in 1945. They had acoustic torps did they not, but I dont think lr guided torps existed at that time

 

[psteel]

The Daring class had the type 170 /174 177 sonars which were designed for the Limbo and were much better than the Type 144 era systems. Friedman reports the type 177 ASDIC was capable of scanning at up to 18,000 yards, against 15kt subs in sea states of 2-3. Type 144 would have been only about 1/3 of that range. SeaKing helicoter with dipping sonar was a hugh advantage and would have had detection ranges in the 10-12ky region although half that in realistic sea conditions.

Most WW-II active sonars were about 1-2 miles or 2-4ky. Looking at weapons effectiveness most WW-II Ballistic weapons were about 15% effective under realistic conditions, while DC attacks would have been maybe 5% against WW-II submarines. Even 1970s ASW torps should be in the 50-70% region against 15 knots submarine.

Thats an order of magnitude increase in effective ASW over the WW-II systems.