Tag Archives: anti-submarine warfare

The Submarine Class that Revolutionized Naval Warfare

Friends of Padre Steve’s World,

I needed a bit of a break from writing about the novel Coronavirus 19 Pandemic. So tonight I answered some kind comments from friends and other people I met on Facebook, as well as wishing my mother a happy 85th Birthday. I also spent time with my Papillon dogs, while eating vegan bean burritos on low carb tortillas, with lots of jalapeño and habanero sauces, while binge watching “The Blacklist” while sipping a dram of an excellent single malt Scotch.

So tonight I have gone back to one of my staples, navy ships, in this case an older article about the class of World War II submarine, the German Type XXI U-Boat, it was a True Wonder weapon, which was the first submarine to truly be called one. So until whenever, I wish you all the best,


Padre Steve+ 

Throughout history there have been ships that have changed the course of naval history, strategy and made previous types of ships obsolete overnight. Such ships included the USS Monitor, the HMS Dreadnought and USS Nautilus are but three, but we have to add to the list the German Type XXI U-Boats which forever changed the way that submarines were built around the world, as well as their deadliness. Now nuclear and diesel electric powered submarines have proven to be nearly undetectable, and are armed with torpedoes to sink surface ships or other submarines, conventionally armed or nuclear armed cruise missiles, even hypersonic ones, and Intercontinental Ballistic Missiles. The are capable of inserting special operations teams, and covertly conducting intelligence operations, and the Type XXI is the ancestor and inspiration for them all.

I was thinking of adding one of the first aircraft carriers to the list of three, but which one would I choose? The HMS Furious, Argus, or Hermès; the USS Langley, Lexington or Yorktown; or possible the IJN Hosho, Akagi, or Kaga? I cannot make that judgment. With the exception of Yorktown all the rest were experimental or conversions of other platforms. The aircraft carrier changed naval warfare, but the Type XXI revolutionized it in a way the aircraft carrier couldn’t. While aircraft carriers grew in size and power, they still remained detectable and their reach limited by the range of the aircraft that they carry. They are incredibly powerful warships and national strategic assets, but they are vulnerable and require the protection of multiple surface ships, and yes, even submarines in order to safeguard them and allow them to survive to ensure that they can survive long enough to complete their missions.

type xxi u-boat SRH025-p40

The Type XXI was designed in 1943 in order to regain the German initiative at sea, and thereby reassert German naval power in the Atlantic in order to turn the tide against the Allies. By 1943 the Allies had turned the tide against the Germans as the Type VII and Type IX U-Boats took heavy losses against naval units and convoys which now had air support of carrier and shore based aircraft at every stage of their trek across the North Atlantic. Likewise, the allied capture of an Enigma coding unit allowed the allies to read any any encoded radio transmission from the U-Boats, and their onshore commanders. Until the invention of the the Schnorchel device, the Type VII and Type IX boats had to surface for prolonged periods in order to recharge their batteries. Likewise they had limited range, speed and endurance when submerged. The same was true of allied submarines, but they did not have to operate against the innovations of the allies. The advent of the Escort Carrier, long range patrol bombers, and hunter killer groups of Destroyers and the new Destroyer Escorts took a great toll on the U-Boat Force. 1943 was the watershed in the U-Boat campaign against the Americans and British. Their losses became onerous when compared to the losses that they inflicted, and for all practical reasons the Germans had lost the war at sea.


U-3008 in U.S. Navy Service

In order to meet the challenge the Germans opted for new technology based on the high speed hydrogen powered Walter turbines for underwater operations. Since these turbines which produced a high underwater speed had short endurance,  the designers modified the design to use conventional diesels, but equipped the boats with batteries that had three times the capacity of previous boats. The Type XXI boats were a radical change from all previous submarine designs which were basically surface ships with the ability to operate underwater for limited periods of time. The Type XXIs were really the first true submarines. They could operate underwater at speeds that were faster than many of their opponents. They had a streamlined hull design which facilitated a higher submerged speed of 18 knots, and enabled silent running making them very difficult to track. They could remain underwater for 11 days while only needing 5 hours to recharge their batteries when using the schnorkel device.


The Wilhelm Bauer the former U-2540 in 1960

The Type XXI had a full streamlined hull and conning tower. Equipment which were externally mounted such as the radio antennae, hydrophones, DF Ring, and forward planes were fully retractable. They had no deck guns, and their twin 20mm flak guns were mounted in a streamlined housing on the conning tower. The German designers eliminated the traditional open bridge in favor of three small openings for the watch officer and 2 lookouts. They had a superior silent running ability and at 15 knots were quieter than the US Navy’s Balao Class that could only make 8 knots submerged. They had a 1 inch thick steel aluminum alloy pressure hull with a designed crush depth of 280 meters (919 feet), a greater designed crush depth greater than any previous submarine. Based on the experience of the Type VII and Type IX boats which often exceeded their designed crush depth by hundreds of feet during the war.

The Type XXI’s incorporated other innovations which would be incorporated into the post-war submarines of the victorious Allied powers. Among these innovations were a semi-automatic hydraulic torpedo reload system which allowed three 6 torpedo salvos to be fired in less than 20 minutes where prior U-Boats had manual reloads which took over 10 minutes to reload a single torpedo. To make the fullest use of this capability the German equipped the boats with an advanced passive and active sonar system called the called Gruppenhorchgerät and Unterwasser-Ortungsgerät NIBELUNG mounted in the bow. The improved passive system sonar system enabled the boats to approach to where they could emit short active sonar bursts to fix the target location without detection. They could fire torpedoes from a depth of 160 feet, far deeper than any other submarine of the era. The torpedoes themselves were an advanced design called the LUT or Lageunabhängiger Torpedo. The LUT was a guided torpedo that could be fired from the U-Boat regardless of the target’s bearing as it was programmed to steer an interception course that was programmed by the torpedo computer.

Submarines influenced by the Type XXI

USS_Gudgeon_;0856710 tang class

USS Gudgeon a Tang Class submarine

ORP_Orzel2 wishkey class

Polish Submarine ORP Orzel a WHISKEY Type Submarine


USS Nautilus on trials

The Type XXI boats were unique in production as they had no prototype and went directly in production. They were assembled from prefabricated sections built from factories around Germany and transported to the major shipbuilding yards by train. This was efficient but caused problems that slowed final assembly as many of the factories had no experience building U-Boats and quality suffered because the exacting specifications required by the Kriegsmarine. Likewise Allied air strikes on German factories and rail networks hampered production.

Yet even in spite of these difficulties 119 Type XXI Boats were completed by the end of the war, although only four were rated as combat ready, and only two were fully operational when the war ended. Of these only one embarked on a war patrol. Most of the remaining boats were destroyed in air attacks while in port, or scuttled by the Germans to prevent their capture.

Eight Type XXIs were taken over by Allied navies at the end of the war where they were used to evaluate their advanced technology for use in future submarines. The U.S. Navy Tang Class boats were heavily influenced by the Type XXI as were the GUPPY upgrades to Balao and Tench class boats. The first nuclear submarines of the U.S. Navy, the Nautilus, Seawolf and the Skate Classes all incorporated design features of the Type XXIs. The Soviet Union developed its 613 and 614 project submarines which became the type known by NATO as the WHISKEY class from the Type XXIs that they received following Germany’s surrender. In 1957 the Federal Republic of Germany raised the scuttled U-2540 and commissioned her as the research submarine Wilhelm Bauer. That boat was operated by both the Bundesmarine and civilian crews until her decommissioning in 1982. She is now a museum ship open to the public in Bremerhaven.

The Type XXIs were the first true submarines and influenced every submarine constructed since. Though introduced too late in the war to make a difference they were truly a wonder-weapon. So until tomorrow when I may or may not resume writing about the novel Coronavirus 19. I just might give myself another day or two break from something that won’t end anytime soon.


Padre Steve+


Filed under Coronavirus, germany, History, Military, Navy Ships, nazi germany, World War II at Sea