Our specifications for environmental conditions are based upon DNV and ABS specifications. [48], Modern examples usually weigh 200 kg (440 lb), including 80 kg (180 lb) of explosives (TNT or torpex). This allowed convoys to be diverted and hunter-killer groups to be targeted on the pack. Some were fitted with a searchlight as well as bombs. A very large chemical mine was designed to sink through ice with the aid of a melting compound. The anchor begins to sink and the mooring cable unwinds until the plummet reaches the sea floor (5). Early mines had mechanical mechanisms to detonate them, but these were superseded in the 1870s by the "Hertz horn" (or "chemical horn"), which was found to work reliably even after the mine had been in the sea for several years. The use of dredging and nets was effective against this type of mine, but this consumed valuable time and resources, and required harbours to be closed. It is slow, but also the most reliable way to remove mines. The US Army Air Forces had the carrying capacity but considered mining to be the navy's job. The helicopter may be solely a weapons carrier or it can have submarine detection capabilities. Following the end of the Russo-Japanese War, several nations attempted to have mines banned as weapons of war at the Hague Peace Conference (1907). [10] It was a watertight keg filled with gunpowder that was floated toward the enemy, detonated by a sparking mechanism if it struck a ship. When the target ship hits the steel cable, the mines on either side are drawn down the side of the ship's hull, exploding on contact. [34] After sweeping for almost a year, in May 1946, the Navy abandoned the effort with 13,000 mines still unswept. Today, most U.S. naval mines are delivered by aircraft. Since World War II, sonar has emerged as the primary method of underwater detection of submarines. Nor does the method change much. The guidance system consisted of four hydrophones placed around the midsection of the torpedo, connected to a vacuum tube-based sound processing array. [citation needed] The whole ship is dangerously shaken and everything on board is tossed around. The models were placed within coils which could simulate the Earth's magnetic field at any location. International law, specifically the Eighth Hague Convention of 1907, requires nations to declare when they mine an area, to make it easier for civil shipping to avoid the mines. These are mines containing a moving weapon as a warhead, either a torpedo or a rocket. Daisy-chained mines are a very simple concept which was used during World War II. The explosion creates a bubble in the water, and due to the difference in pressure, the bubble will collapse from the bottom. Testing of the pre-production prototypes continued on into December 1942, and the US Navy received the first production models in March 1943. However, other Quickstrike versions (MK62, MK63, and MK64) are converted general-purpose bombs. Two mines blew up when the Petropavlovsk struck them near Port Arthur, sending the holed vessel to the bottom and killing the fleet commander, Admiral Stepan Makarov, and most of his crew in the process. Most famously, on 15 May 1904, the Russian minelayer Amur planted a 50-mine minefield off Port Arthur and succeeded in sinking the Japanese battleships Hatsuse and Yashima. A fascinating interview appeared several years ago in the Chinese military magazine 兵工科技 [Ordnance Science and Technology]. On 14 April 1988, USS Samuel B. Roberts struck an Iranian M-08/39 mine in the central Persian Gulf shipping lane, wounding 10 sailors. By contrast, bottom mines are said to be more reliable, harder to find, and much more difficult to sweep. The United States Navy MK56 ASW mine (the oldest still in use by the United States) was developed in 1966. This is frequently the most deadly type of explosion, if it is strong enough. However, opposition from former president John Quincy Adams, scuttled the project as "not fair and honest warfare". Today the weapon firing process is carried out by digital computer with elaborate displays of all relevant parameters. One of the latest anti-submarine weapons, Anti-Submarine ROCkets (ASROCs), SUBROC, the Ikara, the French Malafon, and the Italian MILAS differ from other types of missiles in that instead of having a warhead which the missiles delivers to the target directly and explodes, they carry another anti-submarine weapon to a point of the surface where that weapon is dropped in the water to complete the attack. Mines used in Operation Starvation were supposed to be self-sterilizing, but the circuit did not always work. They can be divided into two main types, the heavyweight, fired from submarines, and the lightweight which are fired from ships, dropped from aircraft (both fixed wing and helicopters) and delivered by rocket.