A Brief History
On May 31, 1942, the Japanese Imperial Navy commenced an attack on the harbor (harbour for you British types) at Sydney, Australia, using three Ko-hyoteki-class midget submarines. With a 2-man crew and armed with a pair of torpedoes, the little subs had the potential to create tremendous damage to any ship afloat. Japan was not the only country to employ midget submarines during World War II, and midget subs were just one of many truly innovative attempts to adapt weapons for special purposes during that war that spawned so much in the way of technological progress. Today we list some of those weapons that strike us as particularly interesting with nifty technology, though you, as always, are welcome to nominate other weapons you believe belong on such a list.
(See our many articles about World War II)
Midget Submarines (Japan, Germany, Italy, UK)
Dangerous duty to the point of being almost a suicide mission, brave men in one or two man tiny submarines (crews would number as many as 5 men) could be used to place explosives on anchored ships (limpet mines), fire torpedoes, or gather up close first hand intelligence about harbors or beaches. Midget subs could be launched from a larger submarine, or even from a surface vessel. Sometimes, the midget sub was nothing more than a man guided torpedo, meant to be a suicide mission. Only Japan employed such a weapon during the war. Called the Kaiten, the suicide torpedo was a measure of desperation by Japan, and combat results are disputed, with generally minimal success attributed to the manned torpedo. Some sources claim an American tanker ship, landing craft and destroyer escort were sunk by Kaitens, with the loss of 187 American lives. Kaiten crewmen killed in action numbered 106. Notable uses of midget submarines included the infamous Pearl Harbor attack on December 7, 1941, when one of the 5 Japanese midget subs deployed managed to torpedo the American battleship West Virginia. In other actions, Japanese midget subs torpedoed the British battleship Ramillies and sank a British tanker. The British used midget subs against the German battleship Tirpitz, sister ship of the Bismarck, while Tirpitz was hiding in a Norwegian fjord. The X-class British sub, with a 3 man crew, managed to mine the giant battleship and cause disabling damage, putting the ship out of commission for a year. Italy made good use of midget submarines in their attack on British ships at the harbor of Alexandria, Egypt in 1941. The manned torpedo Italian midget subs called by their crews “pigs” snuck into the harbor hiding below British ships entering the safety (apparent) of the port, and attached mines to several ships. The mines successfully detonated and sunk 2 British battleships and a Norwegian tanker, while damaging another British destroyer. Most modern navies today field some sort of midget submarines in their fleets.
Guided “Smart” Weapons (US, Germany, Japan)
World War II was indeed a technology war, with measures and counter-measures of all sorts encompassing every part of combat and weapons systems, including, but not limited to, radar and sonar, encoding and code breaking, the earliest computers, jet and rocket engines, metallurgy, proximity fused explosive ordnance, squash head and shaped charge anti-armor weapons, navigation beacons, and exotic systems to keep submarines submerged longer. Among the priorities of scientists and engineers on all sides was to create remotely guided weapons to achieve pin-point accuracy in the delivery of ordnance. Using a manned torpedo or a manned airplane designed to be flown directly into an enemy target was a suicide mission and not really a technological advance, though those were indeed “guided” weapons throughout their entire travel envelope. More sophisticated systems included the German Fritz X, a guided unpowered glide bomb controlled by radio from the bomber aircraft that dropped it and then guided the bomb into the ship or other target aimed at. The Germans used Dornier Do-217 bombers as delivery aircraft and achieved the first known precision guided weapon success by sinking the Italian battleship Roma after the Italians had surrendered to the Allies in 1943. Many other Allied ships were severely damaged by the Fritz X bombs, though the Allies eventually realized the bombs were being guided by the bomber that loitered in the area after dropping the bomb. Thus, the bombers were immediately harassed by whatever antiaircraft fire or interceptors were available in order to disrupt the guidance. Electronic jamming of the radio control signal was also employed to defeat the Fritz X. A rocket powered German guided bomb, the Henschel Hs 293, also achieved some success, sinking or damaging several Allied ships, though it was less successful against land targets such as bridges. Less successful attempts at guided weapons included American efforts to create giant guided bombs by filling heavy bombers with explosives and using remote radio controls to fly them into the target. Unfortunately, the technology was not fully developed, and the flying bombs had to be taken off with a live pilot inside, who would later bail out once the plane was safely on its way and radio control was achieved. Primitive television was also part of the guidance suite. The older brother of John F. Kennedy, later President of the United States, Joseph Kennedy, was killed along with another naval aviator in such an attempt when his explosive laden B-24 bomber blew up with him still at the controls. The program, called Operation Aphrodite, was run in parallel efforts by the US Navy and US Army Air Force, with no real success. Another unsuccessful US stab at achieving precision ordnance guidance was the wacky idea of using pigeons inside glide bombs. The pigeons were expected to observe a video screen and try to land on the deck of the enemy ship (target) below with electric sensors relaying the attention of the bird guidance to the control surfaces. This plan failed and was canceled, though it was revived for a second go around in 1948! One success the Americans had was with their so called AZON guided bomb, which was used to destroy bridges somewhat successfully. Other American efforts at achieving guided bombs did not bear fruit until after World War II. The German Mistel was another ill-fated attempt at a high-tech weapon, using an explosive laden Ju-88 bomber with no pilot slung underneath a smaller, single engine piloted airplane, usually a fighter such as the Fw-190. The pilot would take off the piggy-back plane arrangement, and then jettison the bomber bomb over the target. Though hits were claimed by pilots, the Allies did not record any successful Mistel attacks. Though the British experimented with radio guided bombs, their program was insignificant compared to that of the Germans. Japanese scientists also got on the radio guided bomb band-wagon, including glide bombs and rocket powered bombs as well as heat guided bombs, though the war ended before the effective version of these weapons were produced. Today we have television guided, IR and heat seeking guidance, laser guided, computer program guided, GPS guided, and other sorts of precision guided weapons that have their historical beginnings in World War II.
(Note: Attempts to design air-to-air guided missiles were not successful during World War II.)
Surface to air guided missile (Germany)
As Germany was increasingly plastered by Allied heavy bombers in 1943, German efforts to design a practical Surface to air guided missile (SAM) became urgent, with the result being the Henschel Hs 117, known as the Schmetterling (Buterfly). Using radio controlled guidance by an operator with a telescopic sight, the Hs 117 was equipped with either a photoelectric or acoustic proximity fuse so that the missile just had to get near (10 to 20 meters) the target plane to blow up and hopefully take the offending aircraft down. The weapon was finally ready for production in January of 1945, but the war conditions had deteriorated so badly for Germany that the project was cancelled. A variant was being developed for use in the air to air mode.
Proximity Fuses (US and Germany)
While not a guided precision weapon, proximity fuses allowed both anti-aircraft artillery and anti-aircraft rockets to perform at a much increased effectiveness over the previous timed fuse airburst or impact fused weapons previously employed. The US led the way in this field, especially in the American 5 inch naval gun anti-aircraft role. Proximity fuse technology also created a new breed of airburst artillery shells that spread their effective kill and wound zone beyond that of ground burst artillery shells. Again, the Americans were leaders in this field.
RADAR (Britain, US, Germany, Japan)
While the discovery of radio waves echoing off distant objects was made around the turn of the 20th Century, by the start of World War II the use of radar to detect incoming airplanes and to locate ships at sea for early warning and distant targeting became common. Advances in the technology of radar quickly followed, with radar used as a navigation device for bombing at night and in poor weather, for weather forecasting, and for finding submarines surfaced at night to replenish their batteries and air supply. Radar jamming, both electronic and with metal chaff, became a major priority, and early attempts to create stealthy reduced radar signature forms and coatings began. Radar detectors also became an important device, especially used against German U-boats utilizing radar for self-defense at night. Radar was used to direct anti-aircraft fire and to accurately establish the altitude of incoming bombers as well as to direct fighter-interceptors. Radar even became an effective anti-mortar and artillery tool, detecting the source of incoming mortar and artillery shells, thus enabling counter-battery fire. Night-fighter aircraft were developed with onboard radar sets to allow for accurate shooting at of enemy planes that could not be seen at night. (Radar gunsights were developed just after World War II based on research started during the war.)
Night vision devices (Germany, United States)
Much as the ability of birds to fly caused men to long for the sky, the ability of cats and other creatures to see in dark made men envious, especially military types. People tried to research night vision ability as early as the late 19th Century, with the first success in infrared night vision enhancement technology coming in the 1930’s courtesy of the Dutch firm Phillips, just in time to be developed for use in World War II. In the US, RCA was also developing first generation night vision technology, though it was left to the German army to be the first to field such a device in 1939, though not until 1943 did night vision devices, based on infrared illumination, become more widely used. The US Army also developed and deployed a cumbersome infrared illuminator and vision scope mounted on the M-1 Carbine for use at night, and the systems was used with some success, especially in the Pacific theater. While World War II night vision systems required an infrared illuminator (a large light not visible to the naked eye) in order to work, later systems were able to intensify light well enough to preclude the need for a separate illuminator and even later thermal vision night vision devices would be able to see in complete darkness. It must be noted that the IR illuminator used on early night vision devices was easily seen by the enemy if the enemy had IR viewing equipment, making the use of such devices dangerous to the user.
Question for students (and subscribers): What is your favorite use of innovative technology from World War II? Please let us know in the comments section below this article.
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For more information, please see…
Brown, Louis. A Radar History of World War II: Technical and Military Imperatives. Institute of Physics Publishing, 1999.
Hogg, Ian. German Secret Weapons of World War II: The Missiles, Rockets, Weapons, and New Technology of the Third Reich. Skyhorse, 2016.
The featured image in this article, a photograph of a Japanese Ko-hyoteki class midget submarine, believed to be the vessel known as Midget No. 14, being raised from the bed of Sydney Harbour, is available from the Collection Database of the Australian War Memorial under the ID Number: 060696. This image is of Australian origin and is now in the public domain because its term of copyright has expired.