The accidental discovery of a previously undocumented U-boat wreck by sports divers in 1998 led to its immediate identification as U-480 and the historical correction of the boat's demise. U-480 was previously recorded sunk by depth charges from the HMS Duckworth and HMS Rowley on 24 February 1945. The maritime archeological investigation led by Dr. Innes McCartney proved it was sunk by an underwater magnetic Brazier mine of the D2 minefield that was placed 30 feet off the bottom. The relatively easy identification of U-480 was made through its unique Alberich coating.
The discovery of U-480 provided an accurate assessment of the cause of its sinking, however, it led to a series of incorrect historical conclusions that U-480 was the first operational Alberich coated U-boat employed during the war. That statement is incorrect as U-470 claims that title. U-480 was in fact the first Schnorchel retrofit U-boat equipped with Alberich.
One fact simply often ignored in postwar literature and television documentaries is that Alberich's wartime deployment was directly subordinated to the employment of the Schnorchel. You cannot discuss Alberich without discussing the Schnorchel, as the Schnorchel gave a U-boat the ability to stay submerged and utilize its new acoustic camouflage. Once a U-boat breached the surface, the acoustic camouflage offered no defense from radar or visible location. This meant that as long as a U-boat had to surface to recharge its batteries or maintain pursuit of a convoy while operating as part of a Wolfpack, Alberich was not that useful against its main enemy--radar equipped aircraft. The fate of U-470, a non-Schnorchel equipped U-boat demonstrated this effectively. It was located surfaced in the North Atlantic and sunk on 16 October 1943 by an Allied aircraft. Alberich did not give protection from airborne radar.
Alberich was an ingenious and transformative step forward in the realm of acoustic camouflage that started a path toward anechoic tiles in the postwar period. However, if a U-boat surfaced, Alberich offered no protection, which is why its development was halted in late 1943. It was not seriously considered again until the Schnorchel became operational within the U-boat fleet in the early part of 1944, and the Kriegsmarine realized it could offer added protection as U-boat patrols shifted to exclusively submerged operations. U-boats coated with Alberich could enjoy a reduction of sonar returns by as much as 20% if it operated at the appropriate depth the coating was “tuned”. The various 2mm and 5mm hole patterns differed extensively as to where the Alberich was applied on the U-boat and to what depth the U-boat was going to operate. All Alberich applied to U-boats after U-470 was tuned to shallow water operations.
It must be noted that U-boats operated successfully in the shallow waters around England without the use of acoustic camouflage. They were only equipped with a Schnorchel. U-boats operating in coastal waters utilized a variety of late war tactical procedures to obfuscate their location underwater without the use of Alberich. They hid below thermoclines, varying density layers and even bottoming near existing wrecks to mask themselves acoustically. Alberich enhanced these acoustic camouflage techniques when employed. This is certainly the case for U-480 as its tactical procedures were codified and supplied to all U-boats operating in shallow coastal waters. It should be remembered that there was a limited number of U-boats that received the coating, and an even smaller number that actually conducted a combat patrol with Alberich.
While U-480 was not the first operational U-boat coated with acoustic camouflage, it was the first operational U-boat equipped with both a Schnorchel and Alberich. Its experiences during three war patrols helped inform thinking at BdU on employment and technical development. The tactical procedures adopted by the U-boat's commanding officer, Oberleutnant Hans-Joachim Förster, became the basis of important Experience Messages, as noted below. Another interesting first for U-480 is that it is likely one the first U-boats to receive a Type II snorkel mast. Its conversion from the original Type I taking place in Brest. This also demonstrates that a Type II snorkel installs were retrofit in French ports, a fact also supported by period documents. This understanding is relevant from a maritime archeological perspective as it demonstrates that sunken U-boats located in European waters that are identified with a Type II snorkel may have originated from French, as well as German or Norwegian ports at the time of their sinking.
U-480 was commissioned on 6 October 1943 under the command of Oberleutnant Förster. The Alberich coating was applied between October 1943 and January 1944 while it was assigned as an "experimental boat" in Kiel. This was followed by a Type I Schnorchel install during April, also at Kiel. It received a Ball Float with no Wesch anti-radar coating. After routine training and work ups in the Baltic it returned to Kiel then deployed to Arendal, Norway.
While at Arendal U-480 was assigned as one of the 10 anti-invasion U-boats on standby in Norway. Förster conducted 14 days of Alberich testing out in the Skagerrak starting 20 May. An Ultra intercept received by US Navy's OP-20G noted that U-247 and U-480 would both participate in experiments with the "Communications Experimental Command" followed by a discussion onboard the Minelayer Wullenwever in Arendal Harbor. While the intercept did not disclose the nature of the experiments, they were in actuality ASDIC simulation runs that involved the Alberich coated U-480, and the non-Alberich coated U-247 and U999. The "Communications Experimental Command" had its own cover name known as "Sultan", later identified as such by OP-20G. As per the U-480 KTB, it was assigned to UAG-Schall (Unterseebootsabnahmegruppe Schall) that translates to "U-Boat Acceptance Group – Sound" and NVK-U (Nachrichtenmittelversuchskommando) that translates to "Communication Experimental Command", which had a section for sonar known as U for Unterwasserschall. OP-20G had no inclination what was actually occurring during the tests. The purpose was to conduct sonar runs against a U-boat with acoustic camouflage and one without. During the tests, which apparently proved successful, several issues were identified:
In the course of this testing it was determined by UAG-Schall, that the port propeller at depths over A-20 meters [= 140 meters] and RPM over 170 emits a strong sound. The sound is loud enough to be heard with the naked ear in the boat. At AK the tone disappears, however reappears when the RPM is reduced to 220. Diver examination shows that both propellers are in perfect condition.
During deep dive attempt to depth 1A +20 meters [= 200 meters] snorkel round-dipole antenna flooded.
After the experiments U-480 arrived at Bergen on June 9th for repairs. Four days earlier the Allied invasion of Normandy had begun. The repairs were identified in the boat's log book (KTB) as being a screw change, snorkel round-dipole replacement and supplementary repair of the equipment. The repairs were quick, being completed in 24hrs, but apparently not effective. U-480 departed immediately for the invasion area the next day at 2000hrs on 10 June, and Förster noted in the KTB on the 11th that the Schnorchel round-dipole cable that led into the sound room began to leak a lot of water. As a result, the cable was cut and the conduit sealed.
On the way out from Norway U-480 was attacked by a Catalina while surfaced at 0401 in the morning of 13 June. The Catalina of No. 162 Squadron had departed Wick, England at 2200 on the 12th to patrol the North Sea when it received a flash signal in the early morning hours of the 13th that a U-boat was spotted west of Trondheim. Several Ultra intercepts on the 10th and 12th noted the departure of U-480 from Bergen and its route west, which likely generated the flash report to the Catalina as it was not equipped with radar and Förster had sent no wireless messages that could be triangulated by direction-finding. Förster's alert crew engaged the Allied aircraft with the 3.7cm deck gun scoring a hit despite being staffed and enduring a near miss by a bomb that exploded 20 meters off the starboard side of the U-boat.
After this incident Förster began snorkeling on the night of 15 June for one hour to charge batteries. However, time was of the essence as the invasion of Normandy was well underway. On 17 June BdU ordered U-971, U-715, U-480, U-678, U-423 and U-243 (all VIICs) to proceed to the invasion area "at highest maintainable speed, surfaced as much as possible and on the shortest route", "cruise submerged using snorkel after crossing, approximately, the latitude and longitude of SQ Green YW 80 ((AM 77: 51.27N – 15.15W 'B')). Approach unobserved." There was concern about the snorkel retrofit process, and in the same message transmitted on 19 June BdU added "in case snorkel is out of order, U-boat's report ((the fact)) with passage report."
On 22 June BdU sent another message reiterating "All U-boats report if Schnorchelapparatus is not in order. Give precise data on technical disturbances." In the midst of the Normandy invasion and bitter fighting raging at sea along the invasion route, BdU took the time to notify Förster that his daughter was born that day. He unfortunately would not be given the chance to meet her.
On 1 July Förster noted in the KTB that the Schnorchel seized again. The hydraulic lift for the Schnorchel was leaky and sea water had entered trough he seals. The seals were removed, cleaned and hydraulic lubricant added. The next day BdU ordered U-212, U-243, U-480, U-678, and U-309 to "discontinue outbound cruise; put into Brest." U-480 arrived in Brest on 7 July.
That same day, Förster sent a short report to the 9th U-Flotilla. He noted he did not go into the invasion area in the Channel because he was redirected to Brest. Only a portion of the transmission was intercepted through Ultra. The portion intercepted noted the Catalina attack and other contacts during the passage south but was cut off before further mention of any damage. However, Ultra did intercept the follow-on report passed by 9th U-Flotilla to BdU that same day, which included the damage assessment. It stated "Telemotor Schnorchel cylinder of U-480-Förster is caulked by only two sleeves, completely rusted, severe derangement of periscope apparatus. Pre-combustion chamber stuffing box needed for Brest Front." U-480 went immediately into dry-dock.
During this next four weeks it received an overhaul of the periscopes, the Schnorchel's hydraulic system, installation of a new pressure-air toilet and spring clutch for the port diesel. Most notably it received a complete replacement of the Schnorchel installation. This is important to note, because the only known photo of U-480 that shows its Schnorchel clearly depicts a Type II (non-flange) snorkel install after completing its second cruise. Given how important the Alberich covered U-480 was to BdU, it likely received one of the earliest Type II snorkel installations, replacing its original Type I. Based on all available evidence, German ports only began retrofitting Type II masts in the late summer and early fall. The wreck site clearly reveals that it was equipped with a Ball Float that again had no Wesch anti-radar coating.
On 3 August U-480 departed Brest on its historic cruise into the English Channel's Normandy invasion zone. It was the first Alberich and Schnorchel equipped U-boat with orders to deploy into shallow confined waters and sink Allied vessels. An interesting intercept was recorded by Ultra upon U-480's departure during a routine message from 9th U-Boot Flotilla to BdU. Unfortunately, 165 characters were garbled so the entire message was not read, but it concluded with "snorkel with spring couplings altered on one side." It is not entirely clear what this could mean, other than suggesting that the replacement snorkel for U480 was different than its original and worthy of note to command.
Förster immediately dove after departing Brest and did not surface again for nearly six weeks. BdU sent only two messages to U480 during that time. One on 11 August assigning its patrol area to the north of 50.5N and another on 25 August informing U-480, U-413, U-764, and U-736 to "return to Norway immediately." This latter order was given due to the Allied breakout from Normandy and the isolation of the French U-boat bases.
The first time U-480 surfaced in nearly six weeks was on 12 September at 0503 to send a situation report. Förster noted in his KTB the type of issues expected when a U-boat operates exclusively underwater for more than a month:
Boat stinks bestially of decay and rot. Boat is completely covered with phosphorescent particles. Every step on the bridge stands out shining. If one strokes his hand against the bridge plating, the hand track appears as a bright, shimmering light trace. The upper deck, snorkel recess and all flooding slits phosphoresce [glow] very strongly.
Because of the heavy sea (bridge is constantly awash from astern seas) the men cannot hold on to the slippery wood, I cannot exchange or dismount the weapons. Shields for the twins cannot be folded out. Malfunctions cannot be repaired in the darkness, nor can the cause be determined, apparently the hinges are firmly rusted. The 3.7cm platform is not manned because of the sea state.
Because under these circ*mstances boat would have to proceed on the surface with inoperative weapons, I decide to dive to send my situation message and to plan to continue submerged transit with the use of the snorkel until favorable weather conditions free of rough sea, surfacing during the day or during a bright night for a short time in order to exchange, or dismount, the antiaircraft weapons to allow their repair in the boat. I want to surface for the first time during the day because of the strong phosphorescence to be able to get a picture of the outward condition of the boat.
What Förster documented was how corrosive sea water was on a U-boat submerged for a month. What he noted, specifically, the rusted and inoperable deck guns, became commonplace with Schnorchel equipped U-boats. As in U480's case, many U-boat commanders chose to remain submerged knowing that if they were caught on the surface they would be defenseless.
Förster sent a message at 0522 that read:
Traffic BF 3270 as in Operations Order 7c. Loaded steamer convoys only at night, empty by day. Always many landing craft. Strong surveillance. Search groups, "explosive detection". During depth charge pursuit 5 meters above the bottom. "Alberich very well ". 17-days in the operations area. Sank: 14000 GRT, two frigates, after Lut-triple detonation at 9 min, 20 seconds. 40 days submerged. Anton Lucie 68.
Förster's message was intercepted. OP-20G made a note about the term "Alberich". The note read "Alberich, in German mythology, King of Dwarves, whose Kingdom is under the Rhine. Meaning unknown, but may be cover name for some type of underwater procedure." At the time, the British Admiralty knew of the rubberized coating from the sinking of U-536 and U-470, but the codename "Alberich" was not known by them so there was still no connection made between the rubberized coating and the code word by Allied intelligence.
On 20 November 1943 U536 was sunk by depth charges from the HMS Nene, northwest of Portugal, on its return to France after a patrol in the Gulf of St. Lawrence. Survivors were interrogated. One crewman revealed the existence of "Schwarzes" (Black) U-boats. The same prisoner stated "that there is at present much rumor of a U-boat which can absorb all Radar beams, known as a "Schwarzes (Black) U-boat. He did not believe that trials of this type would be completed before the end of the war." Admiralty Naval Intelligence noted in the interrogation report that "Prisoners from "U-470" also made some mention of a "Schwarzes U-boat". "U-470" was stated to be rubber covered and painted black. She was stated to have carried out trials at Sönderborg, Denmark (N. of Kiel Bay) with this covering for over a year. Such trials are considered unlikely to be successful against ASDIC or Radar." Allied intelligence only made the first tentative connection between Alberich and its anti-ASDIC property on 17 February 1945. In an attempt to understand a variety of German marine mimes, OP-20G noted "that Alberich, reported by U480 ((Foerster: 0401/12 Sept 4)) is King of Dwarfs in same legend and possessor of mantle of invisibility. Alberich almost certainly is anti-ASDIC rubber skin." It was noted that Alberich as well as other unique testing was done in the "Sultan" Group, which was a cover term for the Communications Experimental Group based out of Arendal, Norway.
Admiral Dönitz responded to both Förster and Matuschka in U-482 at 0946 stating "In recognition of your outstanding achievements I award you the German Cross in Gold." Förster's sinking claims were surprisingly very accurate considering how difficult it was to confirm targets while remaining submerged, often without the benefit of even a view from a periscope. On U-480's sortie into the invasion area Förster sunk the Canadian Corvette HMCS Albemi (925 GRT) on 21 August, the British minesweeper HMS Loyalty (850 GRT) on the 22nd, British flagged steamer Fort Yale (7,134 GRT) on the 23rd and British flagged steamer Orminster (5,712 GRT) on the 25th for a total of 14,621 tons. U-480 put into its assigned bunker in Trondheim on 10 October. Eight days later, Hans-Joachim Förster was awarded the Knights Cross to the Iron Cross for his achievements. Dönitz broadcast the award on 19 October to all U-boats:
The Führer has awarded the Knights Cross to Oberleutnant zur See Förster, Commander of U-480, in recognition of his unlimited readiness to serve and his distinguished performance in combat shown during a Channel war cruise. Oberleutnant Förster sank on his cruise 2 Frigates, 2 ships totaling 14,000 tons, and torpedoing another ship.
Förster's final report on his second patrol was detailed and of great interest to BdU. It became the basis of a future Experience Message to the rest of the U-Boat force.
In conclusion, lessons learned are reported:
1) Balancing boat routine.
In an operations area like the Channel is precondition: Tighten discipline within the boat, completely limiting all superfluous activity to conserve air.
2 meal times a day: hot meal at 23.30 hours up to 02.00 hours (depending on snorkel time and depth keeping characteristics). Cold meal at 12.00 hours, otherwise no meals.
A small guard watch was always set, in the boat every light turned off except for 3 to 4 lamps for operation and bilge monitoring.
Waste pressed into boxes and ejected through the "decoy launcher", later now and then also by a "garbage shot" from tube V kept the boat in perfectly clean condition at all times. Food waste was ejected through the compressed air-WC. Without the WC, such a patrol would hardly be possible.
2) Snorkel Lessons Learned:
On the basis of previous snorkel the experiences, which the crew has, as well as good snorkel discipline the snorkel ran perfectly and without difficulties at all times. Personnel difficulties due to excessive strain on the engine personnel did not occur, despite the decrease in the Technical Division by 1 E stoker, 1 diesel stoker and 1 control room leading seaman (current Flotilla Orders), since with the normal submerged transit only small watch was set. Malfunctions and failures were repaired quickly and safely by the staff.
Snorkeling conducted in the operations area was the Brest charging condition (driving diesel 240 RPM, charging diesel 400 RPM. 2000 Amperes battery charging.) Average loading time 2 to 2-1/2 hours. The disadvantage is the large vacuum in the boat which averaged 150 to 180 mb. Even with short undercutting the float valve on again coming free [of the water] tended to stick, so that several times snorkeling had to be interrupted. The reason for the sticking can be found in the large vacuum, which presses against the valve seat so firmly that the weight of the float is no longer sufficient to cause an opening on coming free. This sticking was only observed in a glassy sea, in heavy seas the sticking no longer occurred; probably because then the sea striking against the float causes it to open.
Also the large vacuum resulted in carrying away the battery acid. On 2 September the boat snorkeled in a head sea, sea state 5-6, with Brest charging condition. The boat settled very badly and often cut under. After measuring the batteries one hour after snorkeling began the acid-level of the cells had fallen about 15 to 20 mm. Snorkeling was interrupted. After one hour the old acid level was restored in most cells again or reduced by approximately 5 mm. The acid was for the most part siphoned and ran back again into the cells. The acid wells were all completely filled with acid.
Depth keeping presented no problems in the operations area, because completely calm weather ruled. Most unfavorable are short seas and next to that seas from ahead, then boat is difficult to hold and makes large depth fluctuations. With higher driving speed the boat lies quieter. Experience during this patrol shows that the snorkel speed must not be limited to one or two driving conditions but must be driven in each case by the prevailing conditions. Therefore, after starting the return transit, as long as the situation permitted, to conserve the battery and to avoid a large vacuum, particularly in rough seas, only charged with normal load, equals 1600 Ampere. The driving diesel ran at 240, 270 or 320 RPM according to sea state.
Experienced Speed Levels:
Driving Diesel Charging Diesel Charging per battery
240 RPM 400 RPM 2000 Ampere / hour --
270 RPM 350 RPM 1600 Ampere / hour --
320 RPM 240 RPM 800 Ampere / hour //
320 RPM - - - - 500 Ampere / hour //
Integrated charging
The charging of the battery could be always be completed until the battery was full. The lowest acid level measured in the operations was specific gravity 1.1 at 35 mm and about 30 degrees Centigrade = 6000 ampere hour remaining capacity. To conserve current, lighting and driving current were sharply limited.
Förster's summary does little justice to the overall tactical success he achieved in shallow water operations. U-480 snorkeled daily after midnight and was never detected. Förster bottomed over 40 times during the cruise, utilizing the surrounding thermoclines and rocky conditions to his advantage, enhancing the sound absorption qualities of Alberich. U-480 was overrun by Allied destroyers or frigates using active sonar at least a dozen times but was never detected once. He even used "bottoming" to rest his crew as he did on 24 September at 0606: "Put the boat on the bottom, depth 70 meters. Intention: Because crew is quite exhausted and due to continual unusual knocking [sounds] in the operations area, [they are] quite under a strain. Will remain 1 whole day on the bottom to rest."
Another account from U-480’s log is worth recounting. [U-480] was passed over by convoy FTM 74 on 25th, from which Förster sank a straggler—SS Orminster—with a T5 torpedo. In response to the sinking U480 was hunted for seven hours but escaped his pursuers an account of its acoustic camouflage.
" . .. 25.8.44. 1508. After the previous [sinking], quickly rising sound bearing from turbine propellers, 7 depth charges, seemingly well placed, light damage. Went to depth 45-48 meters and ran off with the easterly current. Boat was pursued by 4 U-boat hunting vessels, 2 with piston engines, 2 turbine powered. 1 piston and 1 turbine powered U-boat hunter with Asdic. 1 turbine powered vessel seemed to specialize in throwing depth charges, in each case starting from 5 to 10 minutes after a pause, throws depth charge series and with the last depth charge deploys the "saw". The last piston powered vessel apparently listened, was observed running at slow RPM. Especially good sound conditions prevail today.
2140. Beginning of dusk. Pursuit lasts until 2200, during which time we have covered five miles over the ground. I have stopped the gyro and refrain from using the hydrophones. I maintain my depth by shifting the crew. One of the A/S vessels frequently lies directly above us with her engines just ticking over, when the least sound aboard her is clearly audible and ASDIC impulses are extremely loud. In these circ*mstances, any boat with a mechanical fault which causes the smallest noise must, at all costs, locate and rectify it. The depth-charge dropper, which has lately been lying stopped, approaches and drops five or six depth-charges, at intervals. These cause such trivial damage that I am convinced that the enemy is unable to locate us by ASDIC and so is without an accurate range. He has merely a hydrophone contact which, because of the absence of noise in the boat, is bound to be vague. I attribute the enemy's failure to locate me, mainly to the protection afforded by Alberich."
U-480's shallow water performance and use of Alberich became something communicated out to other U-boats only in written orders. OP-20G intercepted three wireless messages, one for U-300 sent on 19 January, one for the Alberich coasted U-486 sent on 6 April and one for U-764 sent on the 26th of that month. In each message the following was stated in Paragraph 3: "OP Order 57 in effect. Take along OP Order Kanal Nr 2 and extract from Log of U-480. Equipment for shallow water operation." [Author's emphasis] What this meant remains unclear, but strongly suggests these boats were being issued U-480's 3rd patrol experience from the English Channel as tactical guidance for shallow water operations in conjunction with the use of theGHG Balkon. If so, then the guidance was likely related to the extensive tactic of bottoming that Förster practiced during its patrol.
U-480 remained in Trondheim for two months. This lengthy time in port was most likely due to the cleaning and overhaul required after being submerged for over a month. It is also likely that its Alberich required repairs. U-480's third and final patrol began on 6 January as it left Trondheim for the English Channel. After reaching a point to the west of Ireland, Förster received his orders from BdU on the 19th to head to "your old operational area", according to British intercepts and the BdU KTB. What happened next can only be determined through a maritime archeological examination of the sunken U-boat wreck. A site survey conducted in the 1990s revealed the signs of an external explosion caused by a submerged British mine.
The discovery of U-480 generated much discussion among naval historians and enthusiasts about the role of Alberich as an early "stealth" technology, yet very little about the Schnorchel or new tactics employed with the shift to shallow water operations.
This U-480 case study provides a clear example of the mutually supportive, yet distinct roles of maritime archeology and archival research. A careful assessment of the wreck site revealed the rubber covering that led to its identification, while the observed external damage was linked to the existence of the submerged minefield placed there by the Royal Navy. Yet, the lack of published data about the period of "Total Undersea War" caused a misinterpretation of U-480’s historical context. The critical factor to Alberich's success was the developmental link between the Schnorchel and the acoustic camouflage. While two distinct technical developments, they both served to make the U-boat "invisible". The shift in operations caused by the introduction of the Schnorchel was the catalyst to re-introduce Alberich into the U-boat force. However effective Alberich was, good tactical use of thermoclines and bottoming to hide from Allied ASDIC proved as effective. The tactic of bottoming practiced extensively by Förster became prevalent throughout the U-boat fleet as a result.
