82-655: USS Drexler (DD-741) , an Allen M. Sumner -class destroyer , was named for Ensign Henry Clay Drexler , a Medal of Honor recipient. The Drexler was launched on 3 September 1944 by Bath Iron Works Corp., in Bath, Maine ; sponsored by Mrs. L. A. Drexler, the mother of Ensign Drexler; and commissioned on 14 November 1944. Sailing from Norfolk on 23 January 1945 to escort Bon Homme Richard to Trinidad , Drexler then sailed on to reach San Diego on 10 February. Three days later she got underway for Pearl Harbor for antiaircraft and shore bombardment exercises until
164-685: A museum ship in South Carolina. The first ship was laid down in May 1943, while the last was launched in April 1945. In that time, the United States produced 58 Allen M. Sumner -class destroyers. The Allen M. Sumner class was an improvement of the previous Fletcher class , which were built from 1941 until 1944. In addition to three twin 5-inch/38 caliber gun mounts replacing the Fletcher s' five single mounts,
246-417: A 35–40 lb (16–18 kg) cone-shaped steel drum on a 5 ft (1.5 m) shaft, intended to be thrown at a submarine. Firing Lyddite shells, or using trench mortars , was tried. Use of nets to ensnare U-boats was also examined, as was a destroyer, HMS Starfish , fitted with a spar torpedo . To attack at set depths, aircraft bombs were attached to lanyards which would trigger their charges;
328-462: A comparable WW2 submarine; in addition, they recharged their batteries using a snorkel and could complete a patrol without surfacing. This led to the introduction of longer-ranged forward-throwing weapons, such as Weapon Alpha , Limbo , RBU-6000 , and of improved homing torpedoes. Nuclear submarines , even faster still, and without the need to snorkel to recharge batteries, posed an even greater threat; in particular, shipborne helicopters (recalling
410-403: A device intended for countermining , a "dropping mine". At Admiral John Jellicoe 's request, the standard Mark II mine was fitted with a hydrostatic pistol (developed in 1914 by Thomas Firth & Sons of Sheffield) preset for 45 ft (14 m) firing, to be launched from a stern platform. Weighing 1,150 lb (520 kg), and effective at 100 ft (30 m), the "cruiser mine"
492-410: A large role. The use of nuclear propulsion and streamlined hulls has resulted in submarines with high speed capability and increased maneuverability, as well as low "indiscretion rates" when a submarine is exposed on the surface. This has required changes both to the sensors and weapons used for ASW. Because nuclear submarines were noisy, there was an emphasis on passive sonar detection. The torpedo became
574-407: A large, modern submarine fleet, because all had fallen in the grip of Mahanian doctrine which held guerre de course could not win a war. At the beginning of the conflict, most navies had few ideas how to combat submarines beyond locating them with sonar and then dropping depth charges on them. Sonar proved much less effective than expected, and was no use at all against submarines operating on
656-703: A long tail boom (fixed-wing aircraft) or an aerodynamic housing carried on a deployable tow line (helicopters). Keeping the sensor away from the plane's engines and avionics helps eliminate interference from the carrying platform. At one time, reliance was placed on electronic warfare detection devices exploiting the submarine's need to perform radar sweeps and transmit responses to radio messages from home port. As frequency surveillance and direction finding became more sophisticated, these devices enjoyed some success. However, submariners soon learned not to rely on such transmitters in dangerous waters. Home bases can then use extremely low frequency radio signals, able to penetrate
738-642: A meeting with their American counterparts in June 1917. In October 1918, there was a meeting in Paris on "supersonics", a term used for echo-ranging, but the technique was still in research by the end of the war. The first recorded sinking of a submarine by depth charge was U-68 , sunk by Q-ship HMS Farnborough off County Kerry , Ireland 22 March 1916. By early 1917, the Royal Navy had also developed indicator loops which consisted of long lengths of cables lain on
820-544: A museum ship. The Argentine Navy acquired four Sumners as a more capable adjunct to their previously acquired Fletcher class destroyers. While one was merely to provide spare parts to keep the rest of the fleet serviceable, the other three would go on and serve through the Falklands War , in which they would take a minor role. Soon after the conflict, they were stricken and disposed of. externalities Antisubmarine warfare Anti-submarine warfare ( ASW , or in
902-592: A quadruple 40 mm gun mounting and additional radar for the radar picket mission. 33 ships were converted under the Fleet Rehabilitation and Modernization II ( FRAM II ) program 1960–65, but not as extensively as the Gearing s. Typically, FRAM Allen M. Sumner s retained all three 5-inch/38 twin mounts and received the Drone Anti-Submarine Helicopter (DASH), two triple Mark 32 torpedo tubes for
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#1733085033345984-561: A ram with which to sink submarines, and U-15 was thus sunk in August 1914. During June 1915, the Royal Navy began operational trials of the Type D depth charge, with a 300 lb (140 kg) charge of TNT ( amatol , as TNT supplies became critical) and a hydrostatic pistol, firing at either 40 or 80 ft (12 or 24 m), and believed to be effective at a distance of 140 ft (43 m);
1066-466: A result, in the latter half of 1943, US subs were suddenly sinking Japanese ships at a dramatically higher rate, scoring their share of key warship kills and accounting for almost half of the Japanese merchant fleet. Japan's naval command was caught off guard; Japan had neither the anti-submarine technology or doctrine, nor the production capability to withstand a tonnage war of attrition , nor did she develop
1148-594: A semi-autonomous oceangoing unmanned naval vessel. Today some nations have seabed listening devices capable of tracking submarines. It is possible to detect man-made marine noises across the southern Indian Ocean from South Africa to New Zealand. Some of the SOSUS arrays have been turned over to civilian use and are now used for marine research. Several countries developed anti-submarine missiles including United States , Russia , China , South Korea , Japan and India . Anti-submarine missiles give flexibility in terms of
1230-560: A ship by an underwater vehicle are generally believed to have been during the American Revolutionary War , using what would now be called a naval mine but what was then referred to as a torpedo. Even so, various attempts to produce submarines had been made prior to this. In 1866, British engineer Robert Whitehead invented the first effective self-propelled torpedo, the eponymous Whitehead torpedo ; French and German inventions followed soon thereafter. The first submarine with
1312-499: A similar idea was a 16 lb (7.3 kg) guncotton charge in a lanyarded can; two of these lashed together became known as the Depth Charge Type A. Problems with the lanyards tangling and failing to function led to the development of a chemical pellet trigger as the Type B. These were effective at a distance of around 20 ft (6.1 m). Perhaps the best early concept arose in a 1913 RN Torpedo School report, describing
1394-706: A torpedo was Nordenfelt I built in 1884–1885, though it had been proposed earlier. By the outbreak of the Russo-Japanese War , all the large navies except the Germans had acquired submarines. Nevertheless, by 1904, all powers still defined the submarine as an experimental vessel and did not put it into operational use. There were no means to detect submerged U-boats, and attacks on them were limited at first to efforts to damage their periscopes with hammers. The Royal Navy torpedo establishment, HMS Vernon , studied explosive grapnel sweeps; these sank four or five U-boats in
1476-454: Is used for first detecting, then classifying, locating, and tracking a target submarine. Sensors are therefore a key element of ASW. Common weapons for attacking submarines include torpedoes and naval mines , which can both be launched from an array of air, surface, and underwater platforms. ASW capabilities are often considered of significant strategic importance, particularly following provocative instances of unrestricted submarine warfare and
1558-630: The Knox -class frigates (destroyer escorts prior to 1975), which were commissioned 1969–74 and carried a piloted helicopter, typically the Kaman SH-2 Seasprite , and ASROC. After the Allen M. Sumner s were retired from the US fleet, seven were sunk by the US in fleet training exercises and 13 were scrapped, while 29 were sold to other navies (two for spare parts), where they served for many more years. Twelve were sold to
1640-534: The R1 was the first ASW submarine. 211 of the 360 U-boats were sunk during the war, from a variety of ASW methods: This period saw the development of active sonar ( ASDIC ) and its integration into a complete weapons system by the British, as well as the introduction of radar . During the period, there was a great advance due to the introduction of electronics for amplifying, processing, and displaying signals. In particular,
1722-488: The Admiralty . To attack submerged boats, a number of anti-submarine weapons were derived, including the sweep with a contact-fused explosive. Bombs were dropped by aircraft and depth charge attacks were made by ships. Prior to the introduction of dedicated depth charge throwers, charges were manually rolled off the stern of a ship. The Q-ship , a warship disguised as a merchantman, was used to attack surfaced U-boats, while
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#17330850333451804-485: The Fletcher s, with 12 40 mm guns and 11 20 mm guns compared with the 10 40 mm and 7 20 mm complement typical of a late-war standard Fletcher . The initial design retained the Fletcher s' heavy torpedo armament of 10 21-inch (533 mm) tubes in two quintuple mounts, firing the Mark 15 torpedo . As the threat from kamikaze aircraft mounted in 1945, and with few remaining Japanese warships to use torpedoes on, most of
1886-502: The Mark 44 torpedo , and two new single 21-inch torpedo tubes for the Mark 37 torpedo , with all 3-inch and lighter guns, previous ASW armament, and 21-inch torpedo tubes being removed. Variable Depth Sonar (VDS) was also fitted; however, ASROC was not fitted. Ships that did not receive FRAM were typically upgraded with Mk 32 triple torpedo tubes in exchange for the K-guns, but retained Hedgehog and one depth charge rack. In Navy slang,
1968-499: The Republic of China Navy and two were sold to the Republic of Korea Navy . two were sold to the Iran and one was sold to Turkey . One was sold to Greece .two were sold to Venezuela , two to Colombia , two sold to Chile , five sold to Brazil and four to Argentina . Currently, only USS Laffey (DD-724) , located at Patriots Point , Charleston, South Carolina , remains, as
2050-637: The Second World War , the Allies developed a huge range of new technologies, weapons and tactics to counter the submarine danger. These included: Italian and German submarines operated in the Mediterranean on the Axis side while French and British submarines operated on the side of the Allies. The German Navy sent 62 U-boats to the Mediterranean; all were lost in combat or scuttled. German subs first had to pass through
2132-534: The Sumner s had twin rudders, giving them better maneuverability for ASW work when compared to the Fletcher s. The 5-inch guns were guided by a Mark 37 Gun Fire Control System with a Mark 25 fire control radar linked by a Mark 1A Fire Control Computer stabilized by a Mark 6 8,500 rpm gyro. This fire control system provided effective long-range anti-aircraft (AA) or anti-surface fire. The Allen M. Sumner s also had larger set of short-range anti-aircraft armament than
2214-574: The Whiskey and Zulu classes. Britain also tested hydrogen peroxide fuels in Meteorite , Excalibur , and Explorer , with less success. To deal with these more capable submarines new ASW weapons were essential. This new generation of diesel electric submarine, like the Type XXI before it, had no deck gun and a streamlined hull tower for greater underwater speed, as well as more storage battery capacity than
2296-502: The Wolfpack achieved initial success, but became increasingly costly as more capable ASW aircraft were introduced. Technologies such as the Naxos radar detector gained only a temporary reprieve until detection apparatus advanced yet again. Intelligence efforts, such as Ultra , had also played a major role in curtailing the submarine threat and guiding ASW efforts towards greater success. During
2378-524: The blimps of World War I) have emerged as essential anti-submarine platforms. A number of torpedo carrying missiles such as ASROC and Ikara were developed, combining ahead-throwing capability (or longer-range delivery) with torpedo homing. Since the introduction of submarines capable of carrying ballistic missiles , great efforts have been made to counter the threat they pose; here, maritime patrol aircraft (as in World War II) and helicopters have had
2460-491: The postwar era, ASW continued to advance, as the arrival of nuclear submarines had rendered some traditional techniques less effective. The superpowers of the era constructed sizable submarine fleets, many of which were armed with nuclear weapons ; in response to the heightened threat posed by such vessels, various nations chose to expand their ASW capabilities. Helicopters , capable of operating from almost any warship and equipped with ASW apparatus, became commonplace during
2542-479: The "life and death" urgency in the Atlantic. However, US Vice Admiral Charles A. Lockwood pressured the ordnance department to replace the faulty torpedoes; famously when they initially ignored his complaints, he ran his own tests to prove the torpedoes' unreliability. He also cleaned out the "deadwood", replacing many cautious or unproductive submarine skippers with younger (somewhat) and more aggressive commanders. As
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2624-466: The "range recorder" was a major step that provided a memory of target position. Because the propellers of many submarines were extremely loud in the water (though it doesn't seem so from the surface), range recorders were able to gauge the distance from the U-boat by sound. This would allow mines or bombs around that area to be detonated. New materials for sound projectors were developed. Both the Royal Navy and
2706-526: The 1960s. Increasingly capable fixed-wing maritime patrol aircraft were also widely used, capable of covering vast areas of ocean. The Magnetic Anomaly Detector (MAD), diesel exhaust sniffers , sonobuoys and other electronic warfare technologies also became a staple of ASW efforts. Dedicated attack submarines , purpose-built to track down and destroy other submarines, became a key component as well. Torpedo carrying missiles, such as ASROC and Ikara , were another area of advancement. The first attacks on
2788-591: The 23rd, when she sailed on escort duty to Guadalcanal and Ulithi , the staging area for the Okinawa invasion . Drexler departed Ulithi 27 March 1945 bound for Okinawa and duty on a radar picket station. On 28 May at 07:00, two kamikazes attacked Drexler and Lowry . The first was downed by the combined fire of the two destroyers and planes from the combat air patrol. The second tried to crash onto Lowry but missed, hitting Drexler instead and cutting off all power and starting large gasoline fires. Despite
2870-607: The Allied merchant convoys and strategic shipping lanes to any degree that German U-boats did. One major advantage the Allies had was the breaking of the Japanese "Purple" code by the US, so allowing friendly ships to be diverted from Japanese submarines and allowing Allied submarines to intercept Japanese forces. In 1942 and early 1943, US submarines posed little threat to Japanese ships, whether warships or merchant ships. They were initially hampered by poor torpedoes, which often failed to detonate on impact, ran too deep, or even ran wild. As
2952-463: The First World War. A similar approach featured a string of 70 lb (32 kg) charges on a floating cable, fired electrically; an unimpressed Admiral Edward Evans considered any U-boat sunk by it deserved to be. Another primitive technique of attacking submarines was the dropping of 18.5 lb (8.4 kg) hand-thrown guncotton bombs. The Lance Bomb was developed, also; this featured
3034-553: The Navy developed and introduced the Kyushu Q1W anti-submarine bomber into service in 1945. The Japanese depth charge attacks by its surface forces initially proved fairly unsuccessful against U.S. fleet submarines. Unless caught in shallow water, a U.S. submarine commander could normally escape destruction, sometimes using temperature gradients ( thermoclines ). Additionally, IJN doctrine emphasized fleet action, not convoy protection, so
3116-771: The Pacific, mainly against coastal shipping. In the immediate postwar period, the innovations of the late war U-boats were quickly adopted by the major navies. Both the United Kingdom and The United States studied the German Type XXI and used the information to modify WW2 fleet boats, the US with the GUPPY program and the UK with the Overseas Patrol Submarines Project. The Soviets launched new submarines patterned on Type XXIs,
3198-621: The Type D*, with a 120 lb (54 kg) charge, was offered for smaller ships. In July 1915, the British Admiralty set up the Board of Invention and Research (BIR) to evaluate suggestions from the public as well as carrying out their own investigations. Some 14,000 suggestions were received about combating submarines. In December 1916, the RN set up its own Anti-Submarine Division (ASD), from which came
3280-409: The U.S. Navy fitted their destroyers with active sonars. In 1928, a small escort ship was designed and plans made to arm trawlers and to mass-produce ASDIC sets. Several other technologies were developed; depth sounders that allowed measurement by moving ships were a new innovation, along with a greater appreciation of the properties of the ocean that affected sound propagation. The bathythermograph
3362-433: The US submarine menace was slight in the beginning, Japanese commanders became complacent and as a result did not invest heavily into ASW measures or upgrade their convoy protection to any degree to what the Allies in the Atlantic did. Often encouraged by the Japanese not placing a high priority on the Allied submarine threat, US skippers were relatively complacent and docile compared to their German counterparts, who understood
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3444-506: The aircraft carrier HMAS Melbourne , and never repaired. After the war most of the class (except some of the light minelayers) had their 40 mm and 20 mm guns replaced by up to six 3-inch/50 caliber guns (76 mm), and the pole mast was replaced by a tripod to carry a new, heavier radar. On most ships one depth charge rack was removed and two Hedgehog mounts added. One of the two quintuple 21-inch (533 mm) torpedo tube mountings had already been removed on most to make way for
3526-487: The best ships and crews went elsewhere. Moreover, during the first part of the war, the Japanese tended to set their depth charges too shallow, unaware U.S. submarines could dive below 150 feet (45m). Unfortunately, this deficiency was revealed in a June 1943 press conference held by U.S. Congressman Andrew J. May , and soon enemy depth charges were set to explode as deep as 250 feet (76m). Vice Admiral Charles A. Lockwood , COMSUBPAC , later estimated May's revelation cost
3608-413: The class had the aft quintuple 21-inch torpedo tube mount replaced by an additional 40 mm quadruple mount for 16 total 40 mm guns. The Allen M. Sumner s achieved a 20% increase in 5-inch gun armament and almost a 50% increase in light AA armament on a hull the same length as a Fletcher , only 15 inches (38 cm) wider, and about 15 inches (38 cm) deeper in draft. The increase in standard displacement
3690-646: The class were transferred to the Naval Reserve Force (NRF), with a partial active crew to train Naval reservists. The ships served in the US Navy into the 1970s. DASH was withdrawn from anti-submarine warfare (ASW) service in 1969 due to poor reliability. Lacking ASROC , the Allen M. Sumner s were left without a standoff ASW capability, and were decommissioned 1970–73, with most being transferred to foreign navies. The FRAM Sumners were effectively replaced as ASW ships by
3772-519: The early part of the Pacific War, Japanese subs scored several tactical victories, three successful torpedo strikes on the US fleet carriers Yorktown (CV-5), USS Saratoga and USS Wasp (CV-7), The Saratoga survived the attack and was repaired, while the Yorktown and Wasp were both abandoned and scuttled as a result of the attack. The USS North Carolina (BB-55) received a single torpedo in
3854-399: The end of World War II . While dipping hydrophones appeared before war's end, the trials were abandoned. Seaplanes and airships were also used to patrol for submarines. A number of successful attacks were made, but the main value of air patrols was in driving the U-boat to submerge, rendering it virtually blind and immobile. However, the most effective anti-submarine measure was
3936-440: The endurance of small submarines. Previously the emphasis had been largely on deep water operation but this has now switched to littoral operation where ASW is generally more difficult. There are a large number of technologies used in modern anti-submarine warfare: In modern times forward looking infrared (FLIR) detectors have been used to track the large plumes of heat that fast nuclear-powered submarines leave while rising to
4018-517: The fact a submarine of the day was often on the surface for a range of reasons, such as charging batteries or crossing long distances. The first approach to protect warships was chainlink nets strung from the sides of battleships , as defense against torpedoes . Nets were also deployed across the mouth of a harbour or naval base to stop submarines entering or to stop torpedoes of the Whitehead type fired against ships. British warships were fitted with
4100-409: The heavy damage, she kept firing, aiding in shooting down two planes which attacked immediately after the crash. At 07:03 she was hit by another aircraft, a twin-engined "Frances" P1Y1 bomber , and the impact rolled her on to her beam ends, causing her to sink in less than 50 seconds" at 27°6′N 127°38′E / 27.100°N 127.633°E / 27.100; 127.633 . Because of
4182-497: The helicopter has been used solely for sensing and rocket delivered torpedoes used as the weapon. Surface ships continue to be an important ASW platform because of their endurance, now having towed array sonars. Submarines are the main ASW platform because of their ability to change depth and their quietness, which aids detection. In early 2010 DARPA began funding the ACTUV programme to develop
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#17330850333454264-405: The highly defended Straits of Gibraltar , where nine were sunk, and a similar number damaged so severely they had to limp back to base. The Mediterranean is calmer than the Atlantic, which made escape for U-boats more difficult and was ringed with Allied air bases. Similar ASW methods were used as in the Atlantic but an additional menace was the use by Italians of midget submarines. Operating under
4346-637: The introduction of submarine-launched ballistic missiles , which greatly increased the lethality of submarines. At the beginning of the twentieth century, ASW techniques and submarines themselves were primitive. During the First World War , submarines deployed by Imperial Germany proved themselves to be a capable threat to shipping, being capable of striking targets even out in the North Atlantic Ocean. Accordingly, multiple nations embarked on research into devising more capable ASW methods, resulting in
4428-555: The introduction of escorted convoys , which reduced the loss of ships entering the German war zone around the British Isles from 25% to less than 1%. The historian Paul E. Fontenoy summarised the situation as: "[t]he convoy system defeated the German submarine campaign ." A major contributing factor was the interception of German submarine radio signals and breaking of their code by Room 40 of
4510-457: The introduction of practical depth charges and advances in sonar technology; the adoption of the convoy system also proved to be a decisive tactic. After a lull in progress during the interwar period, the Second World War would see submarine warfare and ASW alike advance rapidly, particularly during the critical Battle of the Atlantic , during which Axis submarines sought to prevent Britain from effectively importing supplies. Techniques such as
4592-502: The largest and longest range vessels of their type and were armed with the Type 95 torpedo . However, they ended up having little impact, especially in the latter half of the war. Instead of commerce raiding like their U-boat counterparts, they followed the Mahanian doctrine, serving in offensive roles against warships, which were fast, maneuverable and well-defended compared to merchant ships. In
4674-409: The main weapon (though nuclear depth charges were developed). The mine continued to be an important ASW weapon. In some areas of the ocean, where land forms natural barriers, long strings of sonobuoys, deployed from surface ships or dropped from aircraft, can monitor maritime passages for extended periods. Bottom mounted hydrophones can also be used, with land based processing. A system like this SOSUS
4756-456: The modified destroyers were called "FRAM cans", "can" being a contraction of "tin can", the slang term for a destroyer or destroyer escort. Many Allen M. Sumner s provided significant gunfire support in the Vietnam War . They also served as escorts for Carrier Battle Groups (Carrier Strike Groups from 2004) and Amphibious Ready Groups (Expeditionary Strike Groups from 2006). From 1965, some of
4838-473: The navy as many as ten submarines and 800 crewmen. Much later in the war, active and passive sonobuoys were developed for aircraft use, together with MAD devices. Toward the end of the war, the Allies developed better forward-throwing weapons, such as Mousetrap and Squid , in the face of new, much better German submarines, such as the Type XVII and Type XXI . British and Dutch submarines also operated in
4920-472: The ocean's surface, to reach submarines wherever they might be. The military submarine is still a threat, so ASW remains a key to obtaining sea control. Neutralizing the SSBN has been a key driver and this still remains. However, non-nuclear-powered submarines have become increasingly important. Though the diesel-electric submarine continues to dominate in numbers, several alternative technologies now exist to enhance
5002-561: The older form A/S ) is a branch of underwater warfare that uses surface warships , aircraft , submarines , or other platforms, to find, track, and deter, damage, or destroy enemy submarines. Such operations are typically carried out to protect friendly shipping and coastal facilities from submarine attacks and to overcome blockades . Successful ASW operations typically involved a combination of sensor and weapon technologies, along with effective deployment strategies and sufficiently trained personnel. Typically, sophisticated sonar equipment
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#17330850333455084-459: The organizations needed (unlike the Allies in the Atlantic). Japanese antisubmarine forces consisted mainly of their destroyers, with sonar and depth charges. However, Japanese destroyer design, tactics, training, and doctrine emphasized surface nightfighting and torpedo delivery (necessary for fleet operations) over anti-submarine duties. By the time Japan finally developed a destroyer escort , which
5166-680: The same attack with the USS Wasp, causing it to miss critical naval actions of the Guadalcanal campaign. Once the US was able to ramp up construction of destroyers and destroyer escorts , as well as bringing over highly effective anti-submarine techniques learned from the British from experiences in the Battle of the Atlantic , they would take a significant toll on Japanese submarines, which tended to be slower and could not dive as deep as their German counterparts. Japanese submarines, in particular, never menaced
5248-428: The same clear-water conditions in the Mediterranean – such that British submarines were painted dark blue on their upper surfaces to make them less visible from the air when submerged at periscope depth – the Royal Navy, mostly operating from Malta , lost 41 submarines to the opposing German and Italian forces, including HMS Upholder and HMS Perseus . Japanese submarines pioneered many innovations, being some of
5330-514: The seabed to detect the magnetic field of submarines as they passed overhead. At this stage, they were used in conjunction with controlled mines which could be detonated from a shore station once a 'swing' had been detected on the indicator loop galvanometer . Indicator loops used with controlled mining were known as 'guard loops'. By July 1917, depth charges had developed to the extent that settings of between 50–200 ft (15–61 m) were possible. This design would remain mainly unchanged through
5412-589: The ships actually monitoring the enemy submarine. Submerged submarines are generally blind to the actions of a patrolling aircraft until it uses active sonar or fires a weapon, and the aircraft's speed allows it to maintain a fast search pattern around the suspected contact. Increasingly anti-submarine submarines, called attack submarines or hunter-killers, became capable of destroying, particularly, ballistic missile submarines. Initially these were very quiet diesel-electric propelled vessels but they are more likely to be nuclear-powered these days. The development of these
5494-414: The ships' range. The Allen M. Sumner s served on radar picket stations in the Battle of Okinawa , as well as other duties, and had several losses. Cooper , Meredith , Mannert L. Abele , and Drexler were lost during the war, and Hugh W. Hadley was so badly damaged by a kamikaze attack that she was scrapped soon after the war ended. In addition, Frank E. Evans was split in half in a collision with
5576-480: The speed with which she sank, casualties were heavy: 168 dead and 52 wounded. The captain was one of the wounded. Drexler received one battle star for World War II service. [REDACTED] This article incorporates text from the public domain Dictionary of American Naval Fighting Ships . The entry can be found here . Allen M. Sumner class destroyer The Allen M. Sumner class
5658-408: The successive generations of Allied airborne radar. The first generation of Allied airborne radar used a 1.7 meter wavelength and had a limited range. By the second half of 1942 the " Metox " radar detector was used by U-boats to give some warning from airborne attack. During 1943, the Allies began to deploy aircraft equipped with new cavity magnetron-based 10-centimeter wavelength radar (ASV III), which
5740-444: The surface, as U-boats routinely did at night. The Royal Navy had continued to develop indicator loops between the wars but this was a passive form of harbour defense that depended on detecting the magnetic field of submarines by the use of long lengths of cable lain on the floor of the harbour. Indicator loop technology was quickly developed further and deployed by the US Navy in 1942. By then, there were dozens of loop stations around
5822-609: The surface. FLIR devices are also used to see periscopes or snorkels at night whenever a submariner might be incautious enough to probe the surface. Satellites have been used to image the sea surface using optical and radar techniques. Fixed-wing aircraft, such as the P-3 Orion & Tu-142 provide both a sensor and weapons platform similar to some helicopters like the Sikorsky SH-60 Seahawk , with sonobuoys and/or dipping sonars as well as aerial torpedoes . In other cases
5904-491: The term "Asdic", but relations with the BIR were poor. After 1917, most ASW work was carried out by the ASD. In the U.S., a Naval Consulting Board was set up in 1915 to evaluate ideas. After American entry into the war in 1917, they encouraged work on submarine detection. The U.S. National Research Council , a civilian organization, brought in British and French experts on underwater sound to
5986-513: The world. Sonar was far more effective and loop technology for ASW purposes was discontinued shortly after the conflict's end. The use and improvement of radar technology was one of the most important elements in the fight against submarines. Locating submarines was the first step in being able to defend against and destroy them. Throughout the war, Allied radar technology was much better than their German counterparts. German U-boats struggled to have proper radar detection capabilities and keep up with
6068-572: Was a group of 58 destroyers built by the United States during World War II . Another twelve ships were completed as destroyer minelayers . The class was named for Allen Melancthon Sumner , an officer in the United States Marine Corps . Often referred to as simply the Sumner , this class was distinguished from the previous Fletcher class by their twin 5-inch/38 caliber gun mounts, dual rudders, additional anti-aircraft weapons, and many other advancements. The Allen M. Sumner design
6150-518: Was also a potential hazard to the dropping ship. During the First World War , submarines were a major threat. They operated in the Baltic, North Sea, Black Sea and Mediterranean as well as the North Atlantic. Previously, they had been limited to relatively calm and protected waters. The vessels used to combat them were a range of small, fast surface ships using guns and good luck. They mainly relied on
6232-526: Was deployed by the US in the GIUK gap and other strategically important places. Airborne ASW forces developed better bombs and depth charges , while for ships and submarines a range of towed sonar devices were developed to overcome the problem of ship-mounting. Helicopters can fly courses offset from the ships and transmit sonar information to their combat information centres . They can also drop sonobuoys and launch homing torpedoes to positions many miles away from
6314-573: Was extended 14 feet (4.3 m) amidships to become the Gearing class , which was produced in larger numbers but did not see significant service in World War II. Completed in 1943–45, four Sumners were lost in the war and two were damaged so badly they were scrapped, but the surviving ships served in the US Navy into the 1970s. After being retired from the US fleet, 29 of them were sold to other navies, where they served many more years. One still exists as
6396-674: Was invented in 1937, which became a common fixture amongst ASW ships within only a few years. There were relatively few major advances in weapons during the period; however, the performance of torpedoes continued to improve. During the Second World War , the submarine menace revived, threatening the survival of island nations like Britain and Japan which were particularly vulnerable because of their dependence on imports of food, oil, and other vital war materials. Despite this vulnerability, little had been done to prepare sufficient anti-submarine forces or develop suitable new weapons. Other navies were similarly unprepared, even though every major navy had
6478-508: Was more economical and better suited to convoy protection, it was too late; coupled to incompetent doctrine and organization, it could have had little effect in any case. Late in the war, the Japanese Army and Navy used Magnetic Anomaly Detector (MAD) gear in aircraft to locate shallow submerged submarines. The Japanese Army also developed two small aircraft carriers and Ka-1 autogyro aircraft for use in an antisubmarine warfare role, while
6560-476: Was only 150 tons, about 7.5%. Thus, the Allen M. Sumner class was a significant improvement in combat power at a small increase in cost. See also the Robert H. Smith -class destroyer minelayer (DM), twelve of which were built on hulls originally intended as Allen M. Sumner s. The Gearing -class destroyers were of the same design, modified with a 14-foot (4.3 m) midship extension to carry more fuel to extend
6642-582: Was strongly influenced by the duel between HMS Venturer and U-864 . A significant detection aid that has continued in service is the Magnetic Anomaly Detector (MAD), a passive device. First used during the Second World War, MAD uses the Earth's magnetosphere as a standard, detecting anomalies caused by large metallic vessels, such as submarines. Modern MAD arrays are usually contained in
6724-600: Was undetectable by "Metox", in sufficient numbers to yield good results. Eventually the "Naxos" radar detector was fielded that could detect 10-cm wavelength radar, but it had a very short range and only gave a U-boat limited time to dive. Between 1943 and 1945, radar equipped aircraft would account for the bulk of Allied kills against U-boats. Allied anti-submarine tactics developed to defend convoys (the Royal Navy 's preferred method), aggressively hunt down U-boats (the U.S. Navy approach), and to divert vulnerable or valuable ships away from known U-boat concentrations. During
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