“Stealth” U-boats
U 480 and the secrets around the “Stealth” U-boats of the Kriegsmarine
Since 2009, usually at late evenings, some TV Channels, such as ARTE or National Geographic, in Britain also ITV, show repeatedly the documentary “From Hunter to Hunted – U 480, the first Stealth U-boat in history” by the authors John Ruthven and Peter Bardehle. It shows video takings from the wreckage of U 480, only 1998 discovered, an U-boat with an unusual outer hull cover made of a rubber kind material, and it clarifies the true end of this boat some day between 29 January and 24 February 1945 after hitting a mine in a British mine field laid southwesterly of the Scilly Islands. Until then, Naval history writing was firmly believing, that U 480 has been sunk by two British warships (24 February 1945 by the frigates HMS Duckworth and HMS Rowley). The newly discovered location of the wreckage is more than 300 nm from the site of U 480´s supposed sinking.
U 480 was the first Kriegsmarine U-boat with a special outer hull coating of the “Alberich” project, which in August 1944 was sent to the front and which achieved the sinking of 2 warships and 2 merchant vessels between 21st and 25 August 1944 in the English Channel, without being detected at all. Apart from U 480, there were at least 10 more U-boats, which have seen tests and trials with the “Alberich” outer hull coating, and some of them have experienced even combat activities, but only two (U 485 and U 1105) survived the end of war and were scrapped later.
Reports passed on, such as war diaries or personal memories from veterans, indicate that other U-boats sent to combat missions had similar positive experiences with such unusual coating, as U 480 had gained, i.e. not being detected by anti-submarine forces despite intensive chasing. In this context, we know of such reports from U 485, U 1105 and U 1107.
The disclosure of project “Alberich” is not new, and much information has been published since decades in specialized books, also many articles were written and lively discussions about could be observed in the known internet chat forums.
In its collection, the German U-boat Museums holds a number of personal memories of former crewmembers of “Alberich” U-boats. However, the “Alberich” story has gained new momentum through the TV documentary. And, not unexpectedly in such cases, some myths about it started to develop, which would like to convert these U-boats rather modernistic to “Stealth” weapon systems or add them to the many so-called “Wonder Weapons” of the Third Reich.
The name “Alberich” was introduced to designate a special outer hull coating of an U-boat, made from synthetic rubber in panel like form, glued on in 2 layers of 2 – 2.5 mm thickness each. The coating was designed to completely suppress own underwater echoes when detected by active Sonar system (In World War II: ASDIC) of anti submarine vessels. It goes back to the king of dwarfs named “Alberich” in the Nordic sagas, who also is known as “Oberon” in the King Arthur myth. During fights, Alberich was able to make himself unvisible by throwing round a special coat.
In the spring of 1940 there were already early trials with rubber coating systems using the type II B U-boat U 11, to minimize and possibly even completely prevent detection of U-boats by Sonar of anti submarine vessels. Further trials were executed in the spring of 1941 with the type IX C U-boat U 67. However, the main pro-blem of pieces of the coating coming off here and there could not be solved, in particular during higher speeds and certain sea states or when touching the ground. Following more trials in the Autumn of 1941 with the Dutch prize submarine UD 4 the newly constructed type VII C U-boat U 480 as 3rd “Alberich” U-boat did receive a complete rubber coating in the Summer of 1943 right from the beginning at its ship yard of Deutsche Werke at Kiel.
U 480 was then the first “Alberich” U-boat to be sent to combat missions. Thereafter, more U-boats under construction were given this novel outer hull cover: The two type VII C U-boats U 485 (Commissioning: 23rd of February 1944) and U 486 (Commissioning: 23 March 1944) at Deutsche Werke, Kiel, three more type VII C U-boats U 1105 (Commissioning: 03rd of June 1944 at Blohm & Voss, Hamburg), as well as U 1106 (Commissioning: 05 July 1944) and U 1107 (Commissioning 08 August 1944), infrastructural deficits (a construction hall for the glueing process independently from weather) caused undefinite delays, allowing the fitting out of two type XXIII U-boats U 4704 (Commissioning: 14 March 1945) and U 4708 (This U-boat was destroyed at its shipyard) at Germaniawerft, Kiel not before early 1945. According to past research some 14 U-boats have been fitted out with such rubber coatings, the first ones for test purposes only, starting with U 480 also as frontal U-boats.
British intelligence knew about this project early. However, amazingly enough there are no analyses by the Royal Navy during the war years 1944 and 1945 known yet, which have examined successful missions by “Alberich” U-boats and drawn conclusion from those. After all, as early as January 1944 the British have gained secured infor-mation from reports by agents or interrogation of U-boat crews in captivity about the trials with rubber coating of U-boats, but were not quite sure about the real purpose of this project. In November 1944 the British Admiral (Submarines) forwarded a summarizing report to the Secretary of the Admiralty about the knowledge gained so
far on rubber coating of German U-boats, concluding, that, with high probability, it must be a technical measure to protect from ASDIC detection. Therefore, not without some reason behind it, the British and the Americans have decided very quickly at the end of the war, to keep U 1105, the famous “Black Panther”, which had surrendered to the Allies in May 1945, from the list of U-boats to be scuttled. Rather, to examine it thoroughly and execute, if deemed necessary, further tests and trials. U 1105 was scuttled by the US Navy in Chesapeake Bay off Virginia as late as 18 November 1948.
Conclusion:
Although the TV documentary of 2009 could clarify the circumstances of the end of U 480, the discussion arising from it has nourished again the my German “Stealth” U-boats and their contribution to the armada of alleged German “Wonder Weapons”. Well, as a starter, the use of the designation “Stealth” is misleading, since it is clearly linked to anti Radar techniques only.
Also, one should be very careful to put “Alberich” to the range of so-called “Wonder Weapons” of the Third Reich. Without any doubt, “Albrich” was a pioneering development and it can prove some success in combat. However, the technique was much too complex for any application, and it was too prone to fail in combat missions, when even light damage to the rubber coating resulted immediately in almost complete loss of the intended camouflage. Consequently, it has never been pursued in submarine construction after the war. Noteworthy, even the Kriegsmarine has never intended to fit their new type XXI “Electro U-boats” with “Alberich” rubber coatings, although this was to be the main weapon system hoped for a technical-operational breakthrough at the end of the war. Therefore, project “Alberich” has been an episode and it was undoubtedly a remarkable engineering achievement, but it was not pursued further, after all. Also, neither the Royal Navy nor the US Navy of the victorious Allies have taken on the idea of rubber coating as a basis for own developments after they had examined the “Alberich” U-boat U 1105 taken over in May 1945. Nowadays, underwater protection of submarines against Sonar detection is achieved by the shape of the hull and an outer skin smoothed by special material. And, as a last argument, “Alberich” U-boats have been detected by Allied anti submarine forces nevertheless, and that by an opponent, who is responsible for more than 40 % of the losses of German U-boats: The aircraft, against any anti Sonar equipment of U-boats does not help very much in the first place.
Sources:
- Deutsches U-Boot-Museum
- Naval Historic Branch Ministry of Defence UK – FDSN1/89
- Eberhard Rössler: “Geschichte des deutschen Ubootbaus”, Volume 1, Bernhard & Graefe, 2nd Edition, Koblenz 1986