In naval warfare, an acoustic mine is defined as one being equipped with a hydrophone that functions as a listening device. This hydrophone listens for particular noises made by any ship or vessel's machinery (propellers). It can also detects structural sounds from the hull of a passing ship. An acoustic mine is mainly operated by a sensitive diaphragm located inside the hydrophone.
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Equipment for countermeasures consist of mechanical mine-hunter MDL-2R, makeshift electromagnetic/acoustic mine hunter PEAM-1 and explosive mine hunter AEL. The Neštin-class is powered by two Torpedo B-539RM/2 engines 121 kW each.
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He was then charged with designing a magnetometer to measure a ship's magnetic field, but he realised that magnetic mines were useless against German E-Boats (motor torpedo boats) that were built with wooden hulls. So he started work on an acoustic mine that worked on the sound emitted by a ship's propeller. He had made a prototype and started testing it when Commander Brown called him in and told him to get back to the magnetometer. He ignored the order and, "with improved security", continued the development of the acoustic mine.
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On 26 September, an acoustic mine detonated under Strahans stern while the corvette was pursuing Chinese pirates. Her rudder was damaged, and she had to be towed into Hong Kong Harbour by sister ship . She was repaired, and returned to Australia. In November, Strahan visited her namesake town.
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For the later two actions, Goldsworthy was awarded the George Medal which was published in a supplement to the London Gazette on 14 April 1944, before receiving a Mention in Despatches in August of the same year. He then engaged in a series of recoveries between 12 June 1943 and 10 April 1944, during which time he defused four German ground mines, three magnetic mines and one acoustic mine. During the defusal of the acoustic mine, which had lain in the water off Milford Haven Wales for two and a half years, Goldsworthy struck his head on the foot of a ladder while underwater and injured his back while trying to get clear.
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The crews of Wild Swan and Beagle, both new to North Atlantic convoy operations, were criticised for keeping a poor lookout.Blair 2000, pp. 208–209.Smith 1985, pp. 112, 114. On 23 December, Wild Swan was departing Liverpool in company with the destroyer when Warwick set off an acoustic mine, and was badly damaged, with the engine room flooded and the ship settling low in the water.
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HMS Elgin was built by the William Simons & Company at their shipyard in Renfrew. She was originally to be named Troon, but was renamed before launch to avoid possible misunderstandings of having vessels named after coastal locations. Elgin was mined on 4 May 1944, 9 miles east of the Isle of Portland, by an acoustic mine. She was towed to Portsmouth and later scrapped.
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The wartime need for oil tankers was so great that only vessels unfit for convoy work were available to Agar. The very poor mechanical condition of these ships hampered the enterprise. Bad weather or mechanical breakdowns forced cancellation of the first attempts. The last attempt seemed set to be successful until the command ship with Agar aboard, , a Hunt class destroyer, hit an acoustic mine mid-Channel and was severely damaged.
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HMS Veteran was damaged by an acoustic mine and required repair. At this time she had her weaponry upgraded with the fitting of 20mm Oerlikon cannons for short range anti-air defence. At the end of September, HMS Veteran was transferred to the Western Approaches Command and based out of Londonderry for Atlantic convoy defence. She escorted several convoys outbound and inbound until involved in a collision with HMS Verity in January 1941.
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While there, her bridge was adorned with a huge stuffed hippopotamus head, acquired by Broome from Formby Golf Club during a spree ashore. Broome also acquired a German torpedo, which had missed its target and run onto the shore of a fjord. Suitably covered in German graffiti, it was eventually handed to the authorities in Rosyth. After the end of the Norwegian campaign, Veteran was assigned to counter a threatened German invasion, and was damaged by an acoustic mine.
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On the night of 7/8 October, an acoustic mine damaged an escorting destroyer with Agar on board; the convoy scattered and the destroyer limped home. Plans were made for another attempt in early November but by then Hitler had postponed Operation Sealion and the Admiralty correspondingly postponed Operation Lucid. The plan was revived in the spring of 1941 but never put into action. War Nawab continued in service as an oil hulk until being broken up in 1958.
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An acoustic mine is a type of naval mine which monitors audio activity in its vicinity. Depending on its design, it will either passively listen to its environment, depending only on the noise that is made by passing ships or actively send out audio pulses, not unlike a sonar, listening to the lapse in time in which the echo returns to it. The mine may freely drift, be moored at a certain location and depth, or lie at the bottom of the ocean floor.
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HQ, A and C Squadrons of 43rd (Wessex) Reconnaissance Regiment were aboard the troopship Derrycunihy, which arrived off Sword Beach on the evening of 20 June. High seas and enemy shelling prevented unloading for three days and it was decided to move to Juno Beach for disembarkation. As the ship started engines it detonated an acoustic mine, splitting the ship in two, and the after part, packed with sleeping men of 43rd Recce Regiment, sank rapidly. Worse still, an ammunition lorry caught fire, and oil floating on the water was set alight.
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Kawasaki also began licensed production of its RTM322 engines during 2005. A specialised mine sweeping and transport model, designated as MCH-101 by the Japan Defense Agency, was produced for the Japan Maritime Self-Defense Force. Special features include the automated folding of the rotor and tail. For the mine-hunting role, the MCH-101 has been outfitted with Northrop Grumman's AQS-24A airborne mine-hunting system and AN/AES-1 Airborne Laser Mine Detection System (ALMDS) for a complete surface-to-bottom mine detection capability, as well as Mk-104 acoustic mine sweeping gear.
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When the Norwegian destroyer was hit by a torpedo on D-Day, despite orders not to abandon the position or to launch lifeboats, he allowed Swift to drift towards the survivors, and was thus able to rescue 80 members of its crew. On 23 June, returning from a night patrol hunting some E-boats, Swift bumped into an acoustic mine that exploded and sank the ship in shallow water. For his actions during the Normandy campaign, Gower was awarded the Distinguished Service Cross. His next command was the destroyer , a ship belonging to the 17th Flotilla of Home Fleet.
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In October 1940, Hambledon was selected to participate in Operation Lucid, a plan to use fire ships to attack German invasion barges in ports in northern France, but bad weather forced the Royal Navy to abort the operation on several occasions and it was never carried out. On 7 October 1940, during operations related to Lucid, she suffered major damage to her after structure from the explosion of an acoustic mine in the English Channel off South Foreland at position , losing one rating killed and two injured. The destroyer towed her to Sheerness, and she was taken to Chatham Dockyard for repairs, which lasted until May 1941, and the installation of Type 285 fire-control radar for her armament.
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Leonard Verdi Goldsworthy, (19 January 1909 – 7 August 1994), known as Leon Goldsworthy, was a distinguished Australian bomb and mine specialist in the Second World War and a recipient of the George Cross, the highest gallantry award for actions which are "not in the face of the enemy" that can be awarded to people of British or Commonwealth nations. He was awarded the GC for defusing four German ground mines, three magnetic mines and one acoustic mine under harrowing circumstances over a period of ten months. By the end of the war, Goldsworthy had achieved the rank of lieutenant commander and was Australia's most highly decorated naval officer. He returned to his home in Perth, Western Australia and became involved in an electrical sign business.
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Japanese MCH-101 The Japan Maritime Self-Defense Force (JMSDF) ordered 14 aircraft in 2003 to use in both the airborne mine countermeasures (AMCM) and transport roles. The AW101 was modified by Kawasaki Heavy Industries, and the Japan Defense Agency designated the model MCH-101. Special features include the automated folding of the rotor and tail. For the mine-hunting role, the MCH-101 has been outfitted with Northrop Grumman's AQS-24A airborne mine-hunting system and AN/AES-1 Airborne Laser Mine Detection System (ALMDS) for a complete surface-to-bottom mine detection capability, as well as Mk-104 acoustic mine sweeping gear.Kawasaki Heavy Industries Showcasing MCH-101 Mine Warfare Helicopter – Navyrecognition.com, 14 June 2017 In 2002, AgustaWestland, Kawasaki and Marubeni entered a general agreement for cooperation; Kawasaki began the assembly of both the CH-101 and the MCH-101 in 2003. Kawasaki also began licensed production of the RTM322 engines in 2005. In a separate agreement between Marubeni and AgustaWestland, a supply depot was established in Japan to support the MCH-101 and CH-101 fleets.
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