Stealth Sub

programmes  —  Deep Wreck Mysteries Series Two  —  Stealth Sub

Stealth Sub – In August 1944, during the 2nd World War, four Allied ships are mysteriously destroyed without warning off the coast of Southern England. Sixty years later, in the English Channel, 20 kilometres south west of the Isle of Wight, 55 metres down, the sea reveals a 2nd World War German submarine unlike any found before. Using revolutionary investigative techniques, a team of underwater detectives discover a story of invention and heroism, and a secret stealth technology. Identified as U-480, it was the first U-boat to go into successful action with a special coating that made it invisible to sonar. But not even this could save the submarine from a fatal trap set by the Allies.

The most effective submarine detection device the wartime Allied Navy develops is ASDIC. It sends out pulses of sound and listens for echoes from the thick steel hull of U-boats. As the war progressed, this and other techniques meant that U-boats from being the hunters became the hunted and the Germans began to lose the submarine war. To regain the upper hand, in August 1944, the Germans dispatch a very special submarine U-480 to lie in wait under the main shipping lanes that cross the English Channel. 4 ships, totalling 14,000 tonnes and including the Canadian warship, HMCS Alberni and the British minesweeper HMS Loyalty were sunk without warning. But how in one of the most heavily-patrolled sectors of the English Channel was the submarine able to make its fatal attacks completely undetected?

Dives down to the submarine 60 years later reveal it is covered in a strange rubber coating. Is this responsible for the submarine remaining undetected? Remarkably a crewmember of the U-480 survived the war and talks about life in the submarine and what he thought was the secret of its success.

But the Allies had a plan to deal with these troublesome submarines. Only now do previously Top Secret files reveal the devious traps they laid and how they enticed the Germans to fall into them. Close examination of the hull of the U-boat shows how she was sunk – with all hands. The secret history of U-480 is followed from the revolutionary invention of the special coating that rendered her invisible, all the way to her brutal demise 55 metres down – and the only survivor finally hears what happened to his ship and shipmates.

As a quick reference positional reporting system, The Kriegsmarine made a map of the world showing all the operation areas of the sea and ocean divided up into squares. The U Boat commanders referred to these squares in their log books or KTBs. For example the place where U 480 sank the HMS Alberni was square BF 3247 - she sailed from Brest BF 5222 and after her missions she docked in Trondheim Norway in AF 8341. During World War 2, the German Navy used a special system to define positions on sea. It did not use the normal longitude and latitude system which is used today but its own system - the so called Marinequadratkarte . This was done to cover the real location of a ship and to find an efficient and short way to report positions via radio transmissions. For example, U-boats had to shadow allied convoys and transmit their position and course quite often to enable other U-boats to get in contact with the convoy and do a simultaneous attack by several boats.

All the U Boats had a mascot or emblem painted on their conning tower. These the U480 has black panther jumping across a four leafed clover. Another Alberich boat the the U 1105 also had a Black Panther. The U 325 had Puss in Boots . Guenther Prien's U Boat the U-47 featured the Snorting Bull and the U-96 and the emblem for the 9th Flotilla at Brest was the Laughing Sawfish. The U 995 preserved at Laboe germany has "fang den Hut" "catch the hat" To learn more about some of these emblems try these links or google further!

As a late war boat the U480 was equipped with a snorkel. Amongst other things his was essential to avoid detection by Allied aircraft especially in the English Channel where the U 480 operated right under the noses of the Allies.The snorkel was introduced to allow the U boats to remain underwater but still make use of their diesel engines. Like everything else on a U Boat, using the snorkel was a fine art. One of the things that could go wrong was if the U Boat went to deep whilst snorkelling and caused the valve to close. If that happened the diesel engines would immediately start using the crew's air from inside the U -Boat. The commander would immediately have to shit down the diesels or get the snorkel going again or the crew would have no air to breathe.

As well as planning his successful attacks Oblt zur .See Hans Joachim Foerster was responsible for every aspect of life on board the U 480. One of the things that most concerned was keeping the boat clean and getting rid of rubbish. From his log book we can read what methods he adopted to do this: Extract from page 46 Ships Log or Kriegstagebuch U 480 2. Unternehmung 8.7.1944 - 4.10.1944 "In an operational area like the English Channel a prerequisite is : Strict on board boat discipline, complete minimisation of any superfluous activity to save air. Two meals per day, hot meal between 23h00 till 02h00 (according to Snorkelling time and attitude of boat) and cold meal at 12h00, no other meals. Stets kleine Wache aufgezogen, any kind of lights in the boat to be extinguished except for 3 or 4 lamps used to control operations and bilges. In order to continually maintain boat in perfect clean state, waste is to be compacted and using flooding procedure later to be flushed out of tube five as "rubbish firing" Foodwaste is disposed of using the air pressure WC. This operation would be impossible with the WC."

The type seven was the most common type of U Boat in the Second World War. around 700 were built in various variations of the same design. According to Gordon Williamson's book Kriegsmarine U Boats 1939 - 1945 (1) "...around 1365 enemy ships were sunk, that total including 190 warships. From the total of just over 700 Type VIIs that were built, over 400 were sunk by enemy action. In the great majority of these cases, the boats were lost with all hands. "

According to Gordon Williamson's book Kriegsmarine U Boats 1939 - 1945 (1) "Of the total of approximately 30,000 U-Boat men who lost their lives in the Second World War around 22,000 or 73 percent were serving on the Type VII."

For people who want to find out what is under the sea around Britain this is a vital port of call. By its own admission the UKHO has been charting the waters around Britain and further afield for 200 years.

Born in 1924 Horst Bredow served during WW2 onboard the U-288. He was not onboard when this submarine was lost with all hands in the Barents Sea. Since the end of the war, Horst has made it his business to commemorate the lives of his former shipmates and all U Boat men by the creation of the Deutsche U-Boote Museum Archiv. Located in Cuxhaven Germany, Horst now in his eighties is now semi-retired but with the help of volunteers maintains a museum and a library of documents covering the history of the men and vessels of the German U Boat Service. The library contains a unique collection of document photographs and letters relation to almost all the thousand plus U Boats that operated in WW2 as well as extensive files on the Imperial German Navy U Boats of WW1.

Deutsche Werke in Kiel built 61 U Boats between 1935 and 1945 as well as the U 480 she built other Alberich boats including the the U 486, the last submarine built at the yard during the wartime. The U 486, also covered in an Alberich rubber skin sank the troopship the SS Leopoldville on Christmas Eve 1944 with a loss of life of over 740 people. After the war in 1955 the Deutsche Werke amalgamated with HDW . That firm is still building ships including U Boats to this day.

Today more known for its engines in trucks, trains and industry the Maschinenfabrik Augsburg Nuernberg or MAN claims to be the home of the diesel engine. In the Second World War MAN engines were fitted to many U Boats. Side by side in the engine room, a central aisle allowed the crewmen to pass between them but not much other room spare.

The U 480 commanded by Oberleutnant sur Zee Hans Joachim Foerster used various torpedoes to sink four ships in the English Channel in the summer of 1944. HMS Alberni single T5 torpedo at 1000m, HMS Loyalty single T5 torpedo 2500m, SS Fort Yale a T3 LUT torpedo and SS Orminster a T5 fired from 3000m range. In common with other navies the early torpedoes used by the Germans were propelled by steam engines driven by compressed air. Development of new models continued through the 1930s and 1940s . The T3 and T5 torpedoes fired by Captain Foerster had electric motors. They therefore left no tell take wake of bubbles. These all found their targets acoustically, hwoever the one which accounted for the SS Fort Yale was T5/LUT or Lageunabhaengige Torpedo. Otherwise known as a pattern runner, this torpedo once fired would turn to the left and to the right at predetermined intervals. The idea was that this by zigzagging in this way it would have a greater chance of hitting a target. Another pattern runner in the German arsenal was the FAT or Flaechen Ab..Torpedo. The FAT capability was typically incorporated within a T5 torpedo. The U Boat firing this weapon no longer needed to be pointing at the ship it wanted to sink as once it started to run the torpedo would steer itself towards the target.

The Alberich coating used to cover the hull of the U480 was made from artificial rubber produced by IG Farben, the consortium of the German Chemical Industry. As an alternative to natural rubber obtained from plantations in places like Malaysia German chemists lead the field in the development of synthetic rubber named Buna S. This scientific knowledge was the starting point for the production of the compounds which would be used to make Alberich. The twin 20 mm rubber sheets ready for fitting to U Boats like U 480 were manufactured by Hoechst in conjunction with German tyre companies Semperit and Continental. Alberich also incorporated an artifical compound called Oppanol developed by BASF in Ludwigshafen. Oppanol is still in use today. It is used for cable insulation and in chewing gum amongst other things.

Due to the danger of detection by Allied forces, German U Boats operating in the English Channel in the second half of 1944 would often spend the daytime lying on the seafloor . After nightfall they would rise up and attempt to sink ships from the many targets that were passing overhead between Britain and France. While lying on the bottom an Alberich covered boat like the U 480 or the U486 would encounter the problem of bottom currents. Pushed by the current they would sometimes be scraped along the bottom and the crew would hear a screeching scraping sound. On top of the noise, sometimes sections of Alberich would be torn off necessitating repairs once the U Boat returned to base.

HMCS Alberni was commissioned on February 4th 1941. She was a Flower Class Corvette and she was named after the Canadian City of Port Alberni on Vancouver Island. The Alberni was one of the first Corvettes built by the Canadian shipyards during World War II. HMSC Alberni escorted convoys and participated in a desperate fight around Convoy SC-42. During this fight 15 merchantmen were sunk and U-501 was destroyed by two other Flower Class Corvettes, HMCS Chambly and HMCS Moose Jaw. During 1942, HMCS Alberni was based in Londonderry and made a name for herself by rescuing over 145 torpedoed merchant seamen on two occasions.

ASDIC, which is now known as sonar, was a secret device for detected submerged submarines by using sound waves. An electric sound transmitter and receiver was housed in a metal dome on the ships hull and sent out high frequency beams were sent out that were audible as “pings” and would bounce back when the hit a submarine. The time taken for the echo was received determined how far away the submarine was and the pitch of the echo would tell the operator which direction the submarine was moving in. A highly trained operator was required to use the ASDIC equipment, however, as the war progressed and the technology improved the ASDIC became easier to operate.

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With Special Thanks to
Royal Naval Historical Branch
DMB Marine Memorial & U995 Laboe
Möltenort Submarine Memorial
Deutsches U-Boot Museum-Archiv
National Codes Centre, Bletchley Park
UK Hydrographic Office
HMCS Sackville / The Canadian Naval Memorial Trust
Ian Taylor - Skin Deep
Steve Brown
Jonathan Watts
James Yates


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