What take the XXI so long?

[BasilY]

It took the IX 2 months from first launch to first patrol. While it took the XXI almost a year. The first XXI were launched in may 1944, just a month before the normandy landings. XXI would have at least slow the torrent of troops and materials flowing onto the continent. Why didn't BdU give a XXI to a veteran submariner, said brandi or Luth, and let them test it in Combat?

[kylania]

Doenitz had been wanting better boats for a long time, or even what he'd been asking for the whole war production wise, but it wasn't till 1943 when he become Commander in Cheif of the Navy and had the ear of Hitler, that he could even start doing anything about it. Even then it was a slow process.

As Commander in Cheif of the Navy he finally was able to push through the development of the XXI and XXIII. He was dealing with the Navy being the red-headed stepchild of production and iron rations of the German military. So at the time he was in charge of ramping up production of all the supplemental boats the Navy needed (minesweepers, e-boats, coastal patrols and the like), deciding if the larger ships were even worth developing or building anymore and keeping his already underfunded and underproduced u-boat fleet growing. He was furthur frustrated by the fact that there were "Navy specific" production plants which if destroyed essentially halted Naval production, while the rest of the armed forces shared production plants and one could easily take the load if another was bombed or something similar.

His orginal plan was to build the "Walter Boats", uboats that would thrive underwater. However, when it was found that these proposed boats weren't even close to being ready for production they got together and fitted a "normal" uboat with a ton of extra batteries for more power, combined with a new assembly line manufacturing processes brought in from the private sector it was found they could make a handful of XXIs before the end of 1944 instead of the 1946 that they were orginally estimated at.

While it seems in hindsight a totally crazy thing to hold back on production on the clearly superior XXIs, at the time it was done pretty quickly indeed, considering all the obstacles in Doenitz' way.

[GoldenRivet]

the XXI was considered by many to be a revolutionary new submarine.

As we all know, many revolutionary new technological developments - especially those developed for military use - are on the drawing board for years sometimes before a working prototype can be developed.

even then - the "final battle ready product" might not exactly be "final" or "battle ready"

The XXI was plagued with problems which required a lot of post-production time to fix and the war ended, or the allies captured ports before most of the XXIs that were built could even be commissioned.

take the II and VII series subs which were available in the mid 30s... they had several years to work out "bugs" before seeing full scale combat.

I hate to say it but in the shallow waters of the english channel - no submarine at the time would have been able to interdict the allied landings and flow of men and materials into the European continent. the water is just too shallow and allied ASDIC was just too good at that point in the war.

any way you slice it, there was pretty much no way the XXI would be the saving grace of Germany during world war two no matter who they put into command of one.

as with several other things... the XXI was just too little too late

[BasilY]

My question is more on the side about the time between the end of construction to actual patrol. In real life, only 2 XXI made combat patrols before the end of the war. What take them so long to get ready?

[GoldenRivet]

XXIs were built inland, nowhere near the ocean... they were built in segments which would be shipped in sections to ship yards and constructed in the modular sense.

this lead to a great number of problems as people who were not experienced ship builders were building the most complicated submarine yet known to man.

the problems had to be fixed before the ship could be put in the water.

problems like . . . segments of the ship not attaching properly, or high pressure air pipes a few inches off in one direction or another.

all of these "little details" lead to a big submarine that was sitting there in pieces waiting to be put together in one of the first attempts in history to build a ship using modular construction... and it was useless in such a condition.

it took a very long time to fix all of the seaworthiness problems JUST to get a boat into the water.

EDIT: i think you are looking at the date of commission and thinking that the boat is ready to go... when in fact the boat is basically named and inducted into the military - the fact remains that just because it has been commissioned doesnt necessarily mean it has been endowed with all of its fighting equipment, stoves, bathrooms, Torpedo data computers etc.

there is still A LOT of work to be done at that point. all of these sub-systems have to be installed, calibrated, tested etc

even a Nimitz class aircraft carrier is completely useless unless she has been fitted with weapons, catapult and recovery systems etc.

[bookworm_020]

GoldenRivet is correct. A post war check done by the Allies showed, while there was great advancement, the boats showed that they had been rushed and were a long way from a perfect fitout. Due to poor fitting, the safe dive depth was half what it should have been, and less than some of the boats it was replacing!

[UnderseaLcpl]

Don't forget the training time neccessary to man the new boats. Even after the production kinks were worked out, the boats required lengthy workups in the Baltic. They were totally unlike any other U-boat, so crews had to be completely retrained. This was one of the chief factors in the abandonment of the Walter boats as well. Their H2o2 fuel systems were dangerous and learning to operate them safely would have taken months.

[GoldenRivet]

excellent points

The logistics involved in building a submarine are incredible... especially if it is a submarine which is to revolutionize submarines

[Dietrich]

By way of comparison, the first Type-XXIII (Type-23, U-2324) was delivered from the shipyard on 17. July 1944 but did not sail on its first combat mission until 18. January 1945... the first of its type to go into service. It didn't contact the enemy until Feb'45. The Type-XXIII is a much simpler boat, smaller and with less complexity (although it was of the same genre as the XXI). Here's a timeline of its development:

21-Apr-1944 : Keel laid. Bauwerft Deutsche Werft AG.
16-Jun-1944 : Launched. Construction and fitting continues.
17-Jul-1944 : U-2324 Delivered
25-Jul-1944 : Acceptance tests completed and ownership transferred to the KM.
29-Jul-1944 : Buoyancy tests in the dock complete. Sailed (on surface only) to Kiel.
03-Aug-1944 : De-magnetisation complete. Sailed to Danzig.
07-Aug-1944 : Arrived at Danzig. Testing commences.
09-Aug-1944 : Minor damage incurred during testing is repaired.
10-Aug-1944 : Equipment overheats. More repairs required.
23-Aug-1944 : First "submerged mile test". Boat needed to surface halfway, due to failure of repairs
06-Sep-1944 : First testing complete. Sailed to Hela.
19-Sep-1944 : Dive plane testing.
21-Sep-1944 : Silent-running motor and propeller noise measured.
28-Sep-1944 : Periscope failure. Sailed to Holm-Werft in Danzig
01-Oct-1944 : New periscope fitted
03-Oct-1944 : U-2324 links up with U-2322 for attack practice
07-Oct-1944 : Due to hydrophone problems, practice aborted. Sent to 26.Flottille for repairs.
12-Oct-1944 : Sailed through the sea canal to Königsberg for hydrophone work.
mid-Oct-1944 : Return to 26. Flottille. Two days testing lost due to bad weather.
late-Oct-1944 : Tests complete. Testing crew depart. Combat crew arrive.
02-Nov-1944 : U-2324 sails for combat testing and outfitting.
04-Nov-1944 : Disrupted by heavy seas.
05-Nov-1944 : Diesel engine failure.
07-Nov-1944 : Arrives at Hamburg.
21-Nov-1944 : USAAF bombs Hamburg. Minor disruption to the shipyard, as only civilian targets were bombed. However, some delays incurred.
23-Nov-1944 : Additional outfitting.
late-Nov-1944 : Water influx into machine room at 9m deep. Fault was an incorrect;y built floor vent.
20-Dec-1944 : Repairs and tests completed.
21-Dec-1944 : Sailed to Tirpitzhafen for Schnorkel testing.
23-Dec-1944 : Schnorkel testing commences. During the first test, the connection cable of the FuMB-Dipole was broken.
25-Dec-1944 : Defective cable repaired.
early-Jan-1945 : Tarnmatte applied to Schnorkel.
09-Jan-1945 : Fitted with combat provisions.
18-Jan-1945 : Sailed for Norway on combat duties.
23-Jan-1945 : Arrived at Horten (Norway). Later sails to Kristiansand-Süd
31-Jan-1945 : Departs for operations area off the Scottish coast.
07-Feb-1945 : First contact with the enemy. No attack due to unfavourable position.
18-Feb-1945 : First attack against a coastal convoy, north east of Sunderland (England). Both torpedoes failed. U-2324 returns.
25-Feb-1945 : Arrives in Kristiansand-Süd.


I know that this is not a Type-XXI, which was the original topic of the thread, but perhaps it might give some ideas as to why it took so long to get the Type-XXI boats into service. The Type-XXI was far more complicated and had a larger crew and more equipment. There were more things to go wrong and, as has already been pointed out, they were a revolutionary (and hence unproven) design.

[BasilY]

Thanks for all your in-depth replies. I will keep my hands off the XXI for my next 100% career.

[flakmonkey]

Originally Posted by Dietrich

By way of comparison, the first Type-XXIII (Type-23, U-2324) was delivered from the shipyard on 17. July 1944 but did not sail on its first combat mission until 18. January 1945... the first of its type to go into service. It didn't contact the enemy until Feb'45. The Type-XXIII is a much simpler boat, smaller and with less complexity (although it was of the same genre as the XXI). Here's a timeline of its development:

21-Apr-1944 : Keel laid. Bauwerft Deutsche Werft AG.
16-Jun-1944 : Launched. Construction and fitting continues.
17-Jul-1944 : U-2324 Delivered
25-Jul-1944 : Acceptance tests completed and ownership transferred to the KM.
29-Jul-1944 : Buoyancy tests in the dock complete. Sailed (on surface only) to Kiel.
03-Aug-1944 : De-magnetisation complete. Sailed to Danzig.
07-Aug-1944 : Arrived at Danzig. Testing commences.
09-Aug-1944 : Minor damage incurred during testing is repaired.
10-Aug-1944 : Equipment overheats. More repairs required.
23-Aug-1944 : First "submerged mile test". Boat needed to surface halfway, due to failure of repairs
06-Sep-1944 : First testing complete. Sailed to Hela.
19-Sep-1944 : Dive plane testing.
21-Sep-1944 : Silent-running motor and propeller noise measured.
28-Sep-1944 : Periscope failure. Sailed to Holm-Werft in Danzig
01-Oct-1944 : New periscope fitted
03-Oct-1944 : U-2324 links up with U-2322 for attack practice
07-Oct-1944 : Due to hydrophone problems, practice aborted. Sent to 26.Flottille for repairs.
12-Oct-1944 : Sailed through the sea canal to Königsberg for hydrophone work.
mid-Oct-1944 : Return to 26. Flottille. Two days testing lost due to bad weather.
late-Oct-1944 : Tests complete. Testing crew depart. Combat crew arrive.
02-Nov-1944 : U-2324 sails for combat testing and outfitting.
04-Nov-1944 : Disrupted by heavy seas.
05-Nov-1944 : Diesel engine failure.
07-Nov-1944 : Arrives at Hamburg.
21-Nov-1944 : USAAF bombs Hamburg. Minor disruption to the shipyard, as only civilian targets were bombed. However, some delays incurred.
23-Nov-1944 : Additional outfitting.
late-Nov-1944 : Water influx into machine room at 9m deep. Fault was an incorrect;y built floor vent.
20-Dec-1944 : Repairs and tests completed.
21-Dec-1944 : Sailed to Tirpitzhafen for Schnorkel testing.
23-Dec-1944 : Schnorkel testing commences. During the first test, the connection cable of the FuMB-Dipole was broken.
25-Dec-1944 : Defective cable repaired.
early-Jan-1945 : Tarnmatte applied to Schnorkel.
09-Jan-1945 : Fitted with combat provisions.
18-Jan-1945 : Sailed for Norway on combat duties.
23-Jan-1945 : Arrived at Horten (Norway). Later sails to Kristiansand-Süd
31-Jan-1945 : Departs for operations area off the Scottish coast.
07-Feb-1945 : First contact with the enemy. No attack due to unfavourable position.
18-Feb-1945 : First attack against a coastal convoy, north east of Sunderland (England). Both torpedoes failed. U-2324 returns.
25-Feb-1945 : Arrives in Kristiansand-Süd.


I know that this is not a Type-XXI, which was the original topic of the thread, but perhaps it might give some ideas as to why it took so long to get the Type-XXI boats into service. The Type-XXI was far more complicated and had a larger crew and more equipment. There were more things to go wrong and, as has already been pointed out, they were a revolutionary (and hence unproven) design.

Even with the XXIIIs simpler construction the yards still struggled with the new designs, their biggest screw up with the typ23s was the shipyards estimated crush depth of 425m, in reality it turned out to be only 80m!

[Hanomag]

Hah!! Let's see Wikipidia top that for infos!!

[Murr44]

Originally Posted by Hanomag

Hah!! Let's see Wikipidia top that for infos!!

Many Wikipedia entries have serious factual errors and/or the information lacks proper sources. I take Wikipedia with a grain of salt.

That's a very interesting & thorough timeline. Thanks for sharing.

[Jimbuna]

Apologies if it's already been mentioned, but slave/enforced labour was increasingly the norm near the wars end due to the fact most of the experienced/skilled labour was drafted into an ever deteriorating land defence situation.

This labour was notorious for being way below expected standards, in one book I've read, reference is made to a pseudo welded seam....the worker or workers had packed an oil stained rope between the plates to look like a weld had been performed.

Can you imagine the suprise in store as soon as the U-boat made her first out of port trim dive.

[Murr44]

Originally Posted by jimbuna

Apologies if it's already been mentioned, but slave/enforced labour was increasingly the norm near the wars end due to the fact most of the experienced/skilled labour was drafted into an ever deteriorating land defence situation.

This labour was notorious for being way below expected standards, in one book I've read, reference is made to a pseudo welded seam....the worker or workers had packed an oil stained rope between the plates to look like a weld had been performed.

Can you imagine the suprise in store as soon as the U-boat made her first out of port trim dive.

Good point.

Many experienced factory workers who up to that point had been exempted from military service were now being drafted into the Volkssturm or hastily raised Volksgrenadier divisions. Their replacements were often forced labourers who lived and often died in appalling conditions: starvation, disease, beatings & the ever-present threat of summary execution. They certainly had no reason to ensure that the quality of their work was of the highest standard.