Action of 9 February 1945
Encyclopedia
The Action of 9 February 1945 refers to the sinking of the German
U-boat
U-864 in the North Sea
off the Norwegian
coast during the Second World War
by the Royal Navy
submarine
HMS Venturer
. This action is the first and so far only incident of its kind in history where one submarine has intentionally sunk another submarine while both were fully submerged.
, which aimed to deliver highly sensitive technology to Germany's wartime ally, the Empire of Japan
. She also carried a number of Japanese experts; these were Tadao Yamoto (Japanese acoustic torpedo expert) and Toshio Nakai (Japanese fuel expert). Also included were two Messerschmitt
engineers, Rolf von Chlingensperg and Riclef Schomerus. On 6 February 1945, U-864 passed through the Fedja area without being detected. During this voyage the normally quiet engine started to make an abnormally loud and rhythmic noise that could be easily detected by any ASW
equipment in the area. Since there were many Allied (primarily British) ASW ships, submarines and aircraft in the area, U-864s commander, Ralf-Reimar Wolfram
, decided to return to the pens at Bergen
to repair the problem.
By this stage of the war the German naval code, Enigma, had been broken by British mathematician Alan Turing
and his cryptanalytics team at Bletchley Park
using a device called the Bombe
. The German naval command was unaware of the fact that the British were reading communications sent to the U-boat fleet and were aware of Operation Caesar
. Wanting to avoid giving the Japanese any advantage that might allow them to extend the duration of the war in the Pacific, Royal Navy submarine command dispatched Venturer to intercept and destroy U-864.
HMS Venturer was now on her eleventh patrol out of the British submarine base at Lerwick
in the Shetland Islands
. Under the command of 25-year-old Jimmy Launders
Venturer had sunk thirteen German vessels during ten patrols over the previous 12 months, including the destruction of the Type VIIc U-Boat U-771
off the Lofoten Islands on 11 November 1944, 7 nautical miles (13 km) east of Andenes
.
Launders received a brief message from Royal Navy Submarine Command as to the estimated whereabouts of U-864, that she was somewhere near the island of Fedje
, off Norway's southwest coast, just north of the pens at Bergen, along with instructions to destroy her. Launders set about the task, making one risky but calculated decision: he decided to switch off Venturers ASDIC (ASDIC being the British term for sonar
). They would rely solely on Venturer's hydrophone
, a common and long-used, though far less sophisticated underwater acoustic detection device than ASDIC, to try to detect U-864 along the course that the Enigma-encoded traffic suggested.
ASDIC/Sonar is an active echo location system; it can quickly provide enough data on range and course for a target's speed and bearing to be calculated, and a firing solution for a weapon to be arrived at, even against a vessel taking evasive action. It is also quite a directional system - akin to a headlight's beam. Its classic use in World War II was on surface vessels hunting submarines, giving off its characteristic 'ping'. However - the ping can be heard by the target as well, and the ping can be heard much further away than the returned echo that indicated a target. Hydrophones however are passive devices, simply very sensitive underwater microphones that in basic terms can tell an operator where a noise is coming from; working out distance and speed are much more difficult, especially if a vessel takes evasive action. It also requires the hunting vessel to move quite slowly to as not to mask out any external noises by its own sound signature.
Launders' choice was to hide and see if he could hear the U-Boat in the area. It is like being in a dark hall, looking for someone dressed in black. For Launders, using his ASDIC would have been like using a small torch; if he was very lucky the target would be close, and he might just be looking in the right direction to see his target by the glow of his torch. However the target could not fail to notice the torch being lit, and then take action against their hunter. Launder's plan was to listen for the U-Boat's footsteps and stalk her.
The Engima intercepts led Launders' commanders to direct him to search for the U-864 near Fedje; however U-864 had already left the area on her mission to Japan. Wolfram's decision to return for repairs at the U-Boat pens
at Bergen to fix the abnormal engine noise problem brought U-864 back past Fedje and the area where HMS Venturer was patrolling.
operator noticed a strange sound which they could not identify. The hydrophone operator thought that the noise sounded as though some local fisherman had started up a boat's diesel engine. Launders decided to track the strange noise. Then the officer of the watch on Venturer's periscope noticed what they thought was another periscope above the surface of the water. However it is highly likely that what was seen was the snorkel of the U-Boat. The snorkel device was still a new device, at that time only used by U-Boats; it was probably unknown to Launders and his crew, which is why it was thought to be a periscope. The snorkel was a rigid tube raised to the surface to allow the U-Boat to run on her diesels while submerged, saving precious battery life. It allowed air to enter both for the engines and the crew, plus was also used as an outlet for exhaust fumes. Thicker and bulkier than a periscope, it also limited the U-Boats speed and depth. For Launders' hydrophone operator to hear diesel noises from a submerged U-Boat, the snorkel would have had to be in operation. In addition, the diesel noise made the U-Boats own hydrophones much less useful so it is doubtful the German hydrophone operator will have heard Launders running slowly on his electric motors.
Combined with the hydrophone reports of the strange noise, which he determined to be coming from a submerged vessel, Launders surmised that they had found U-864. Launders tracked U-864 by hydrophone, hoping it would surface and allow a clear shot. But U-864 remained submerged, and as the hydrophone plot emerged, was seen to be zigzagging. This made U-864 quite safe according to the assumptions of the time.
Launders continued to track the U-Boat. After several hours it became obvious that she was not going to surface, but he needed to attack it anyway - his batteries had only limited life. It was theoretically possible to compute a firing solution in all four dimensions - time, distance, bearing and target depth - but this had never been attempted in practice because it was assumed that performing the complex calculations would be impossible, plus there were unknown factors that had to be approximated.
In most torpedo attacks, the target would have been visually acquired; the target's angle relative to the attacker and its bearing would be observed, then various range finding devices used to establish distance to target; from this speed could be derived, and a basic mechanical computer would offset the aiming point for the torpedo. In addition, torpedo depth had to be set based on target identification. Too deep and the torpedo would pass under the keel, too shallow and it would not do as much damage especially if it was a warship with an armoured belt at the waterline. Launders could only estimate the depth of his target - and even then his torpedoes could go over or under the U-Boat's hull. In terms of a challenge, this was far outside what they had trained for, as they tried to manoeuvre into a firing position without giving their own position away by creating excessive noise, or exhausting their own batteries.
Nevertheless, Launders and his crew made the necessary calculations, made assumptions about U-864s defensive manoeuvres, and ordered the firing of all torpedoes in the four bow tubes (as a small, fast-attack boat, Venturer was equipped with only four tubes in the bow, none in the stern, and carried a full complement of only eight torpedoes), with a 17.5 second delay between each shot, and at variable depths. U-864 attempted to evade as they heard the torpedoes coming, but the Type IXD2 boats were big and not as quick to dive or turn as Launders' own type of attack boat; additionally time would have been needed to drop the snorkel, call the crew to action stations, disengage the diesel, and start the electromotors. The fourth torpedo struck the target. U-864 instantaneously imploded with the loss of all hands.
U-864 sank 31 nautical miles (57 km) from the relative safety of the U-Boat pens in Bergen. The attempt of U-864s crew to avoid enemy ASW detection by repairing the noise problem is what put them and their vessel in harm's way, as it brought her back through the waters around Fedje, where Venturer was lying in wait. Launders was awarded a bar to his DSO
for this action, while several of Venturers crew were decorated by the Royal Navy. Launders' career in the Navy continued well after the war. U-864 was the last U-Boat sunk as the result of enemy action prior to the end of the war on 8 May 1945. The action was also the first and so far only battle ever to have been fought entirely under water.
The wreck of U-864's was discovered in 2003, lying in 460 feet (140.2 m) of water 2.2 nautical miles (4.1 km) west of the island of Fedje. The wreck is classed as a War Grave
, and all maritime operations relating to the wreck, including environmental clean-up efforts, must adhere strictly to the international protocols dealing with treatment of such sites.
Nazi Germany
Nazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...
U-boat
U-boat
U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...
U-864 in the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
off the Norwegian
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
coast during the Second World War
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
by the Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...
submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
HMS Venturer
HMS Venturer (P68)
HMS Venturer was a Second World War British submarine.-Construction:Venturer was the lead boat of the British V class submarine, a development of the successful U-class...
. This action is the first and so far only incident of its kind in history where one submarine has intentionally sunk another submarine while both were fully submerged.
Background
The U-864 was a Type IX U-Boat, designed for long ocean-going voyages far from home ports with limited re-supply. She was on a highly-sensitive, long-range, covert mission codenamed Operation CaesarOperation Caesar
Operation Caesar was a secret mission carried out by Germany in World War II to supply Germany's faltering ally, Japan, with advanced technology to fuel their war machine...
, which aimed to deliver highly sensitive technology to Germany's wartime ally, the Empire of Japan
Empire of Japan
The Empire of Japan is the name of the state of Japan that existed from the Meiji Restoration on 3 January 1868 to the enactment of the post-World War II Constitution of...
. She also carried a number of Japanese experts; these were Tadao Yamoto (Japanese acoustic torpedo expert) and Toshio Nakai (Japanese fuel expert). Also included were two Messerschmitt
Messerschmitt
Messerschmitt AG was a famous German aircraft manufacturing corporation named for its chief designer, Willy Messerschmitt, and known primarily for its World War II fighter aircraft, notably the Bf 109 and Me 262...
engineers, Rolf von Chlingensperg and Riclef Schomerus. On 6 February 1945, U-864 passed through the Fedja area without being detected. During this voyage the normally quiet engine started to make an abnormally loud and rhythmic noise that could be easily detected by any ASW
Anti-submarine warfare
Anti-submarine warfare is a branch of naval warfare that uses surface warships, aircraft, or other submarines to find, track and deter, damage or destroy enemy submarines....
equipment in the area. Since there were many Allied (primarily British) ASW ships, submarines and aircraft in the area, U-864s commander, Ralf-Reimar Wolfram
Ralf-Reimar Wolfram
Ralf-Reimar Wolfram was a German Korvettenkapitän during World War II. During his career he commanded two U-boats for a total of 118 days at sea spanning four patrols. During his third patrol he successfully sunk the , an American liberty ship...
, decided to return to the pens at Bergen
Bergen
Bergen is the second largest city in Norway with a population of as of , . Bergen is the administrative centre of Hordaland county. Greater Bergen or Bergen Metropolitan Area as defined by Statistics Norway, has a population of as of , ....
to repair the problem.
By this stage of the war the German naval code, Enigma, had been broken by British mathematician Alan Turing
Alan Turing
Alan Mathison Turing, OBE, FRS , was an English mathematician, logician, cryptanalyst, and computer scientist. He was highly influential in the development of computer science, providing a formalisation of the concepts of "algorithm" and "computation" with the Turing machine, which played a...
and his cryptanalytics team at Bletchley Park
Bletchley Park
Bletchley Park is an estate located in the town of Bletchley, in Buckinghamshire, England, which currently houses the National Museum of Computing...
using a device called the Bombe
Bombe
The bombe was an electromechanical device used by British cryptologists to help decipher German Enigma-machine-encrypted signals during World War II...
. The German naval command was unaware of the fact that the British were reading communications sent to the U-boat fleet and were aware of Operation Caesar
Operation Caesar
Operation Caesar was a secret mission carried out by Germany in World War II to supply Germany's faltering ally, Japan, with advanced technology to fuel their war machine...
. Wanting to avoid giving the Japanese any advantage that might allow them to extend the duration of the war in the Pacific, Royal Navy submarine command dispatched Venturer to intercept and destroy U-864.
HMS Venturer was now on her eleventh patrol out of the British submarine base at Lerwick
Lerwick
Lerwick is the capital and main port of the Shetland Islands, Scotland, located more than 100 miles off the north coast of mainland Scotland on the east coast of the Shetland Mainland...
in the Shetland Islands
Shetland Islands
Shetland is a subarctic archipelago of Scotland that lies north and east of mainland Great Britain. The islands lie some to the northeast of Orkney and southeast of the Faroe Islands and form part of the division between the Atlantic Ocean to the west and the North Sea to the east. The total...
. Under the command of 25-year-old Jimmy Launders
Jimmy Launders
James "Jimmy" S. Launders DSO & Bar, DSC & Bar was an officer in the British Royal Navy during and after World War II. He retired from the service in 1962, but continued to serve in an unofficial capacity on training programs until his death in 1988...
Venturer had sunk thirteen German vessels during ten patrols over the previous 12 months, including the destruction of the Type VIIc U-Boat U-771
German submarine U-771
German submarine U-771 was a Type VIIC U-boat of the German Kriegsmarine during World War II. She was ordered on 21 November 1940, and was laid down on 21 August 1942 at Kriegsmarinewerft, Wilhelmshaven, as 'werk 154'...
off the Lofoten Islands on 11 November 1944, 7 nautical miles (13 km) east of Andenes
Andenes
is a town and former municipality in Vesterålen district in Nordland county, Norway.Andenes was separated from Dverberg January 1, 1924. It was merged with Dverberg and Bjørnskinn to create the new municipality of Andøy January 1, 1964....
.
Launders received a brief message from Royal Navy Submarine Command as to the estimated whereabouts of U-864, that she was somewhere near the island of Fedje
Fedje
Fedje is an island municipality in the county of Hordaland, Norway. Fedje was separated from Austrheim on 1 January 1947.The main island of Fedje is surrounded by about 125 smaller islands and rocks mostly north of the main island, and the name Fedje applies both to the main island, and to all the...
, off Norway's southwest coast, just north of the pens at Bergen, along with instructions to destroy her. Launders set about the task, making one risky but calculated decision: he decided to switch off Venturers ASDIC (ASDIC being the British term for sonar
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...
). They would rely solely on Venturer's hydrophone
Hydrophone
A hydrophone is a microphone designed to be used underwater for recording or listening to underwater sound. Most hydrophones are based on a piezoelectric transducer that generates electricity when subjected to a pressure change...
, a common and long-used, though far less sophisticated underwater acoustic detection device than ASDIC, to try to detect U-864 along the course that the Enigma-encoded traffic suggested.
ASDIC/Sonar is an active echo location system; it can quickly provide enough data on range and course for a target's speed and bearing to be calculated, and a firing solution for a weapon to be arrived at, even against a vessel taking evasive action. It is also quite a directional system - akin to a headlight's beam. Its classic use in World War II was on surface vessels hunting submarines, giving off its characteristic 'ping'. However - the ping can be heard by the target as well, and the ping can be heard much further away than the returned echo that indicated a target. Hydrophones however are passive devices, simply very sensitive underwater microphones that in basic terms can tell an operator where a noise is coming from; working out distance and speed are much more difficult, especially if a vessel takes evasive action. It also requires the hunting vessel to move quite slowly to as not to mask out any external noises by its own sound signature.
Launders' choice was to hide and see if he could hear the U-Boat in the area. It is like being in a dark hall, looking for someone dressed in black. For Launders, using his ASDIC would have been like using a small torch; if he was very lucky the target would be close, and he might just be looking in the right direction to see his target by the glow of his torch. However the target could not fail to notice the torch being lit, and then take action against their hunter. Launder's plan was to listen for the U-Boat's footsteps and stalk her.
The Engima intercepts led Launders' commanders to direct him to search for the U-864 near Fedje; however U-864 had already left the area on her mission to Japan. Wolfram's decision to return for repairs at the U-Boat pens
Submarine pen
A submarine pen is a bunker which is designed to protect submarines from air attack.The term is generally applied to submarine bases constructed during World War II, particularly in Germany and the occupied countries which were also known as U-boat pens .-Background:Amongst the first...
at Bergen to fix the abnormal engine noise problem brought U-864 back past Fedje and the area where HMS Venturer was patrolling.
Action
As Venturer continued her patrol of the waters around Fedje, her hydrophoneHydrophone
A hydrophone is a microphone designed to be used underwater for recording or listening to underwater sound. Most hydrophones are based on a piezoelectric transducer that generates electricity when subjected to a pressure change...
operator noticed a strange sound which they could not identify. The hydrophone operator thought that the noise sounded as though some local fisherman had started up a boat's diesel engine. Launders decided to track the strange noise. Then the officer of the watch on Venturer's periscope noticed what they thought was another periscope above the surface of the water. However it is highly likely that what was seen was the snorkel of the U-Boat. The snorkel device was still a new device, at that time only used by U-Boats; it was probably unknown to Launders and his crew, which is why it was thought to be a periscope. The snorkel was a rigid tube raised to the surface to allow the U-Boat to run on her diesels while submerged, saving precious battery life. It allowed air to enter both for the engines and the crew, plus was also used as an outlet for exhaust fumes. Thicker and bulkier than a periscope, it also limited the U-Boats speed and depth. For Launders' hydrophone operator to hear diesel noises from a submerged U-Boat, the snorkel would have had to be in operation. In addition, the diesel noise made the U-Boats own hydrophones much less useful so it is doubtful the German hydrophone operator will have heard Launders running slowly on his electric motors.
Combined with the hydrophone reports of the strange noise, which he determined to be coming from a submerged vessel, Launders surmised that they had found U-864. Launders tracked U-864 by hydrophone, hoping it would surface and allow a clear shot. But U-864 remained submerged, and as the hydrophone plot emerged, was seen to be zigzagging. This made U-864 quite safe according to the assumptions of the time.
Launders continued to track the U-Boat. After several hours it became obvious that she was not going to surface, but he needed to attack it anyway - his batteries had only limited life. It was theoretically possible to compute a firing solution in all four dimensions - time, distance, bearing and target depth - but this had never been attempted in practice because it was assumed that performing the complex calculations would be impossible, plus there were unknown factors that had to be approximated.
In most torpedo attacks, the target would have been visually acquired; the target's angle relative to the attacker and its bearing would be observed, then various range finding devices used to establish distance to target; from this speed could be derived, and a basic mechanical computer would offset the aiming point for the torpedo. In addition, torpedo depth had to be set based on target identification. Too deep and the torpedo would pass under the keel, too shallow and it would not do as much damage especially if it was a warship with an armoured belt at the waterline. Launders could only estimate the depth of his target - and even then his torpedoes could go over or under the U-Boat's hull. In terms of a challenge, this was far outside what they had trained for, as they tried to manoeuvre into a firing position without giving their own position away by creating excessive noise, or exhausting their own batteries.
Nevertheless, Launders and his crew made the necessary calculations, made assumptions about U-864s defensive manoeuvres, and ordered the firing of all torpedoes in the four bow tubes (as a small, fast-attack boat, Venturer was equipped with only four tubes in the bow, none in the stern, and carried a full complement of only eight torpedoes), with a 17.5 second delay between each shot, and at variable depths. U-864 attempted to evade as they heard the torpedoes coming, but the Type IXD2 boats were big and not as quick to dive or turn as Launders' own type of attack boat; additionally time would have been needed to drop the snorkel, call the crew to action stations, disengage the diesel, and start the electromotors. The fourth torpedo struck the target. U-864 instantaneously imploded with the loss of all hands.
Aftermath
Distinguished Service Order
The Distinguished Service Order is a military decoration of the United Kingdom, and formerly of other parts of the British Commonwealth and Empire, awarded for meritorious or distinguished service by officers of the armed forces during wartime, typically in actual combat.Instituted on 6 September...
for this action, while several of Venturers crew were decorated by the Royal Navy. Launders' career in the Navy continued well after the war. U-864 was the last U-Boat sunk as the result of enemy action prior to the end of the war on 8 May 1945. The action was also the first and so far only battle ever to have been fought entirely under water.
The wreck of U-864's was discovered in 2003, lying in 460 feet (140.2 m) of water 2.2 nautical miles (4.1 km) west of the island of Fedje. The wreck is classed as a War Grave
War grave
A war grave is a burial place for soldiers or civilians who died during military campaigns or operations. The term does not only apply to graves: ships sunk during wartime are often considered to be war graves, as are military aircraft that crash into water...
, and all maritime operations relating to the wreck, including environmental clean-up efforts, must adhere strictly to the international protocols dealing with treatment of such sites.