Mine Warfare and Clearance Diving Forces
The offensive mine warfare capabilities of the ADF as of 2000 were in the form of air dropped mines, while a submarine launched mining capability was under development. Six Huon class coastal minehunters were entering service at that time. These units hunt for mines by means of a high definition sonar and remote controlled underwater vehicles. The Huon class also have a limited minesweeping capability. They are designed to possess the smallest possible acoustic and magnetic signature to reduce their vulnerability to mines actuated by these methods. Two smaller Rushcutter class inshore minehunters possessed similar capabilities, although their smaller size and lower speed meant that they were more limited in their operational flexibility. Craft of opportunity, converted tugs, fishing vessels and other small craft, can also be used to tow devices to clear minefields or confirm that areas are clear of threats.
The activities of all these units are controlled by a Mine Warfare Command Support System, a mobile shore command facility which is organised to plan and coordinate mine clearance operations and which can be moved rapidly around the country to the area under the greatest threat.
Clearance Diving Teams assist with the identification and rendering safe of devices, particularly in shallow water and in ports and harbours. They can also conduct clandestine hydrographic surveys of beaches for amphibious operations and clear mines or obstacles. Other elements within Clearance Diving Teams can conduct underwater battle damage repair of fleet units, as well as support tasks involving the fitting and repair of underwater fittings. The rendering safe and disposal of all explosive ordnance including improvised explosive devices is a core skill of all Clearance Diving Team elements.
The sea mine has been used in Australian waters forboth offensive and defensive purposes. Minefields were an important part of port defences during the colonial era and, during World War II, they were used to seal off many of the passages through the Great Barrier Reef. In both world wars, German surface raiders laid offensive minefields that sank a number of Allied merchant ships in Bass Strait and off the east coast. The Japanese also conducted a limited offensive mining campaign in Australian waters. During 1942-43, their submarines laid mines off Darwin and Brisbane, and in the Torres Strait. Most of the fields consisted of moored contact mines that required a ship to physically strike the chemical horn in the mine. Off Brisbane, however, the Japanese laid influence ground mines that detonated in response to either the noise or magnetic field produced by a passing ship. Fortunately, the Japanese fields were all cleared before they could claim a victim.
During World War II, RAN minesweeping squadronswere based at Sydney, Melbourne, Hobart, Adelaide, Fremantle, Darwin, Brisbane and Newcastle. HMAS Bathurst (I) was the first of sixty Australian minesweepers, commonly known as corvettes, built during World War II in Australian shipyards as part of the Commonwealth Government's wartime shipbuilding program. Twenty (including Bathurst (I)) were built on Admiralty order, but were manned and commissioned by the RAN. Thirty-six were built for the RAN and four for the Royal Indian Navy. Australia also had a mining capability with the HMAS Bungaree, which laid approximately 10,000 mines in Australian and New Zealand waters during the war. Additional minefields were laid to defend the main Australian ports.
After the war, the RAN's minecounter-measures capabilities were engaged in clearing mines from Australian and regional coastal areas continuously from 1945 until 1950. In 1950, with the clean up complete, the RAN operationof mine counter-measures vessels effectively ceased, although the Clearance Diving Branch was established in 1951 with officers and sailors of from the Render Mine Safe Branch.
It was not until 1962 that the RAN re-acquired asurface-ship mine counter-measures force, with six Ton-class minesweepers of which two were converted into mine-hunters. These ships were capable of mechanical and influence sweeping, a speed of 16 knots, an armament of 40/60 Bofors (two prior to 1968), radar and sonar. They served as patrol vessels in the Indonesian Confrontation in 1964 and were decommissioned in 1990.
With an on-going requirement for a surface-ship minecounter-measures capability, the RAN explored innovative ways in which to maintain it. Two key projects in the mid-1980s were the Mine Hunter Inshore (MHI) and the Craft of Opportunity. MHIs, HMAS Rushcutter and Shoalwater were commissioned in 1986 and 1987 respectively. Built to a catamaran design for operations in sheltered waters and with a displacement of 170 tons, they were not suitable for mine-hunting operations beyond the immediate area of ports and waterways. The ships also fulfilled a vital training role, maintaining practical mine-warfare skills in the RAN, thereby retaining a core-level of expertise on which tobuild when the coastal mine hunters were introduced. The two MHIs were decommissioned in August 2001.
The two Mine Sweeper Auxiliaries, Bandicoot and Wallaroo, were originally built in 1982 as commercial tugsand operated in Singapore. The RAN acquired both vessels in August 1990 to support visits to Australia by nuclear-powered warships on the eastern seaboard and provide an auxiliary mine counter-measures capability. Both vessels had a ship's complement of 10 personnel and, apart from the technical sailors onboard, were crewed predominantly by mine warfare sailors. These ships provided an excellent capability in their primary role of support to visiting nuclear warships from Hobart to north Queensland ports. Both vessels also had a secondary role as mine-sweeping platforms, towing mechanical and influence sweeps; they were also used as training mine-sweeping vessels; and they occasionally conducted route survey operations. They were limited byspeed and weather (less than sea state four) and, due to age, were removed from the RAN inventory.
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