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.

[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

[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

[Hartmann]

Originally Posted by 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

I´m agree , i think that the war in the channel was lost since the england battle.

Nothing can stop the huge flow of the allied landings, except a good air superiority or the same streng compared with allied forces.

If the luftwaffe don´t changed the tactic of bombing airfields and aircraft factories by the london blitz , england would be finally surrender by starvation.

[Jimbuna]

Originally Posted by Hartmann

I´m agree , i think that the war in the channel was lost since the england battle.

Nothing can stop the huge flow of the allied landings, except a good air superiority or the same streng compared with allied forces.

If the luftwaffe don´t changed the tactic of bombing airfields and aircraft factories by the london blitz , england would be finally surrender by starvation.

Highly debatable,,,,the RAF were beginning to struggle, true, ut the Luftwaffe aircraft didn't have the range to reach the far west of England or Ireland should the air assetts have been so repositioned.

Don't forget also, the Luftwaffe were taking extreme losses during the whole process.

Morale of the Luftwaffe aircrews was at an all time low at that point.

I doubt they had the stomach to fight against such mounting losses for much longer.

[Murr44]

Originally Posted by 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

A little off topic but another example of this would be the Panther. It was conceived & developed through late 1941 and 1942. Rushed into production, it's debut during Operation Citadel (Kursk) was hardly auspicious. Many of the 200 model D Panthers that had been assembled for the operation broke down or were destroyed by engine fires before they saw any combat at all. The tank's problems included under powered engines; the tank grossly exceeded it's initial design weight, and weak final drives. These bugs were not really solved until the introduction of the model G and by then it was far too late for the Panther to have turned the tide for the Germans.