Type XXI U-boat

I've heard some say that the Type XXI elektroboote was the first true submarine by today’s standards. It had a very streamline hull and an advanced propulsion system. It was faster underwater than any of its predecessors’ and it had freezers to keep food fresh It also had the latest snorkel designs, and a superior battery system letting it stay submerged for longer periods.

If the Kriegsmarine had advanced working models of the Type XXI electric boats used as the workhorse during the "Gluckliche Zeit" (instead of the VIIC), and thereafter, how would the battle of the Atlantic be changed?

I dare say it would indeed make the u boat hunters jobs more difficult and prolong the struggle, but the end result might be the same. The Ubootwaffe would still eventually be overcome.

However, I'm not 100 percent sure.

 

might be good to try and find a nice book for your collection : The UBoat by Eberhard Rössler. A classic volume !

 

Well i dare to say, that if the type XXI would be mass produced, it wouldn't be good for American and British navy. But since only two were sent to the end of a war, even those were more or less hiding and waiting for the end.
But to get to the point:
type XXI was the design, that changed the way of nautical sub-warfare. Since it had a point designed to be fast and agile in water, it had a total speed of 32km per hour subbed and 29km. p. h. on a top of water.
They were planed to have (and did have) 6 automatic torpedo tube loaders, so they fired fishes in 10 minutes. All six. The manual loading lasted the same time lenght for one.
The diving area was 280m in depth.

 

Two Type XXIs were fully operational, however, another 113-115 were completed and in the process of completing their training.

The Type XXI is considered the first "modern" submarine, because it was the first to be designed to spend most, if not all, of its time underwater. All preceding submarines spent most of their patrols on the surface, submerging only to attack or when in danger.

The Type XXI was fast underwater, however, it was not agile. The Type XXI had a single rudder and the propellers were angled slightly away from it. Thus the rudder did not get the full effect of the prop wash, so the Type XXI was somewhat sluggish in turning.

The torpedo reloading rig was not automatic, but semi-automatic. Still, reload times were greatly reduced.

The crush depth of 280 meters is only an estimation, the deciding factor was the quality of the welding job performed when connecting the different hull modules. The Germans said the safe depth was 180 meters, the deepest test dive performed by a Type XXI was 220 meters. In tests performed post-war: the US crushed U-2513 at 274 meters, while the British crushed one of their Type XXIs at 243 meters.

What DUKW left out was that the Type XXI was very quiet for its time. The "Creep" motor allowed the Type XXI to cruise almost noiselessly at 6 knots. IIRC, post-war testing by the USN showed that the Type XXI traveling underwater at 15 knots made as much noise as a US Balao doing 8 knots.

 

Of course, the Allies were at least somewhat aware of the Type XXI and were in the process of putting systems in place to combat it. These included:

Automatic scanning sonars that searched in a wide pattern rather than the previous 'searchlight' types with an 11 degree beam that were manually scanned.
Lower frequency sonars with more range and better detection rates.
Three dimensional sonar set ups that gave range bearing and depth. This was critical for such systems as Limbo and Squid.

New ASW weapons like Limbo, Squid, Weapon Alpha, trainable hedgehog, homing torpedoes, and the like were just coming into service to combat the fast submarine.

Directional sonobouys and active search measures like "Julie" were also starting to be used by aircraft. Blimps were getting the first dipping sonar units where they could lower a pinger into the water and search like a ship could. Helicopters got these post war.

So, both sides were improving their equipment.
IR detectors and diesel 'sniffers' were in development particularly for aircraft to run down snorkeling subs from a greater distance.

 

MAD was also coming into use. Then there was the tendency of the type XXIs to self destruct.

 

MAD was already in general use aboard aircraft and, in some cases, ships as early as 1942. The USN had made it their primary detection means for aircraft but reversed this by 1943 in favor of Sonobouys with MAD providing an accurate targetting method after localizing the sub using sonar.

 

Thanks for the info. I hadn't seen any dates on US usage. I do remember that late in the war the Japanese were starting to use it.

 

What T.A. Gardener forgot to say, was that Soviets also took a part of research of those XXI subs. You can see it in the older generations of russian and american subs. They have mostly the same construction. Yet some things are much more brushed by each of the factions.
Yeah I really forgotten to say about silenced engines. Thx Takao.

 

Yes, the type XXI was the design, that changed the way of nautical sub-warfare. The XXI-boats were their time and the technical standards around 20 years ahead. Although both sides were improving their equipment these boats would have changed the situation for a longer time, especially because the speed of boats subbed made them a very dangerous weapon for all kind of battleships and the convois.
The plans for the construction were destroyed in april 1945 in Blankenburg/Harz. The people of this small city told that it took several days before all the papers burned to ashes.

 

Well, it is one of the designs that changed the way of submarine warfare. Throughout the history of submarine design, the have been several that changed submarine warfare.

Not really, 10 years after the XXI came the USS Nautilus(SSN-571). Although the Type XXI did set the way for immediate post-war development of submarines around the world.

This is highly debatable. While, the Type XXI would have had a great advantage immediately following its introduction to combat, the Allies would soon have several counters for it, T. A. Gardner pointed out several Allied ASW projects in post #6 of this thread. Remember, the nature of combat is not stagnant, it is always changing. The Type XXI's speed was an advantage, however, it could only maintain its top speed underwater for about an hour before its batteries were dead.

 

The XXI-boats were a compromise, because there wasn´t enough time to develope these XXI-boats on the main-constructions of XVII-boats (the "Walter"-boats). That means that the XXI-boats had to be constructed much larger than the XVII boats to integrate the traditionell drive system.

 

The Type XXI was designed as a large ocean going submarine for long distance patrol in the same mold as the earlier Type XI. The Type XXVI "Walther" boats were designed as coastal submarines with limited endurnace and torpedo loads. There was also a coastal version of the Type XXI the type XXIII. It like the XXVI had limited endurance and torpedo capacity. One of this boat's real dangers, shared with the XXVI, was that it had very low freeboard and a very small positive bouyancy. This was done to make them hard to spot surfaced and allow them to dive quickly. But, it also meant that even a small amount of flooding would sink one. This happened at least a couple of times post war to the several boats that remained in service in the Bundeswher where a wave washed over the boat and water spilled in through the conning tower hatch sinking it.

Of course, the Type XXVI would almost have certainly proved a massive, and dangerous, failure in service. Every nation that expeirmented with HTP (High Test Peroxide aka H2O2) had their disasters with it. The British built two subs, Meteor and Explorer using this. Both had several serious fires and accidents in service and were withdrawn after very short service lives.
The Russians tried the same with their Zulu class. Essentially, these were Foxtrot subs modified for use with HTP. They built like half-a-dozen. These also quickly proved horribly dangerous and were withdrawn from service and rebuilt as normal electric boats.

Anyway, the idea of high underwater speed is hardly a German-only phenomenia. The Japanese too started experimenting very early on higher underwater subs. Their first attempt was a demonstration boat given the camoflauge name Experimental Boat No 71. This was a small coastal type sub of about 200 tons surfaced that carried three torpeodes and could make 25 knots submerged at maximum ehp.

By 1943 the Japanese started to lay down a class of Sensui Taka Sho (small fast submarines). These boats could do 13 knots submerged, weighted about 350 tons and had 2 torpedo tubes and 4 torpedoes. They were designated Ha 201 to about 280. About half a dozen were completed by the end of the war.
They also laid down the Sensuikan Taka class I 201 -223 of high speed large submarines starting in late 1943. These boats resembled the Type XXI in capacity. They had 4 tubes and 10 torpedoes aboard, could manage 19 knots submerged and weighted about 1300 tons surfaced. At least 3 were completed prior to the end of the war with several more building.
Post war the US tested these off Hawaii just as they did with captured German Type XX1 boats. Both captured boats led the US to begin its GUPPY program to upgrade their existing fleet boats for greater underwater speed.
So, the Germans were not alone in trying and building high speed submarines in WW 2.

 

First off, you have confused the TypeXVII with the TypeXVIII. The Type XVIII is the submarine the Type XXI is based on. The Type XXI is only some 5 meters longer than the Type XVIII. Hardly what one would call "much larger." Second, the major difference between the two boats was that the area used to store the fuel, Perhydrol(H2O2), for the Walther boat, now stored electric batteries. The project was dropped for a few reasons. Some being; Perhydrol was in a very limited supply and the vast quantities to supply a fleet of submarines would not be available for some time. It was also realized that the Type XVIII would not be combat ready for quite some time too. Thus the decision was made to go ahead with the Type XXI, which could be made combat ready in a reduced time span and it would not require the precious and highly dangerous Perhydrol.

 

And if your not talking about the engine, the USS Albacore(AGSS-569) was commissioned roughly nine months before the USS Nautilus. Either way, the Type XXI was not 20 years ahead of her time. Although, the Soviet navy did use her design as the basis for several types of submarines, so what you say may hold true when the Type XXI is compared to the submarines of the Soviet Navy.

 

Having played many, many, many battles in Silent Hunter III armed with the XXI-class, all I can say is that you can kill a lot of merchants and capital ships and survive the destroyer onslaught afterwards