Defense Technology International - April 2008 - (Page 41) ENGINEERING SUBMARINE VITAL SIGNS Australian sub program targets propulsion technologies ABRAHAM GUBLER•DARLING HARBOR, AUSTRALIA he Royal Australian Navy is developing designs for a new generation of diesel-electric submarines that will replace its six Collins-class boats beginning in 2020. The specifications will be very di erent from those of conventional submarines now in use around the world. They will include high transit speeds, long endurance in difficult environments and greater acoustics processing—capabilities associated with nuclear attack submarines (SSN). The program will be the costliest ever undertaken by the Australian military— the price has been put at A$25 billion ($23 billion) to build, equip and operate the submarines. Royal Australian Navy (RAN) designers have a wealth of technology to choose, mostly in propulsion and energystorage systems. Ongoing developments in these areas have the potential to yield diesel-electric submarines that are fast, quiet, energy-e cient and able to operate e ectively anywhere in the world. RAN classifies the Collins boats as guided-missile submarines (SSG) to differentiate them from the more common T hunter-killer diesel-electric subs (SSK). Unlike navies with SSKs, Australia’s SSG subs face very long-range transits to reach patrol areas. SSKs usually have patrol areas co-located with their home bases or at most 1,000 naut. mi. away. Australia’s SSGs transit at least 1,600 naut. mi. to reach the Timor Sea and 4,500 naut. mi. to reach the Persian Gulf or Sea of Japan. The SSGs are consequently much bigger than SSKs, with features like larger crew spaces, three diesel generators rather than two and full-time air-conditioning. Collins-class subs displace 3,050 tons (surfaced), 1.7 times that of Germany’s Type 209/1500 SSK, 1.4 times Canada’s Victoria-class SSK and 1.3 times Russia’s Project 636 SSK (NATO designation Kilo). Australia’s future submarine program will emerge through a rigorous procurement model starting around 2010 that will see a new design compete with a commercial off-the-shelf (COTS) design for construction by an alliance of government and industry. The Australian Defense Dept. calls the project “Sea 1000: The Future Underwater Warfare System.” The COTS option will be based on Collins-class design and technology, with enhancements for changing requirements like littoral and land-attack operations and, if space and weight allow, a secondary air-independent propulsion (AIP) system. The Australian Defense Dept.’s Capability Development Group is fleshing out the design. Experts say it will continue the limitations of the Collins-class boats, in particular their slow transit speed. Collins was specified with a submerged transit speed of 16 kt. over 10,000 naut. mi. This was reduced to 10 kt. over 9,000 naut. mi. due to the limitations of technology at the time (the first-of-class boat entered service in 1996). When a conventional submarine transits, it spends about 70% of each day running on the battery and the other 30% “snorting,” or recharging with the snorkel. Transit speed is determined by the battery’s stored energy, the power needed to run the motor and the submarine’s ability to generate electricity while sustaining transit speed. Most SSKs maintain 8 kt. submerged. New technology in electric motors, generators and energy storage makes the original transit speed achievable. The high-power-density electrical systems will boost sprint and tactical speeds and meet the need for hotel power to run combat management systems (CMS) and improve habitability. The development and fielding of hightemperature superconductors (HTS) has enabled production of electric motors and generators that are at least 20-35% the weight and less than half the volume of legacy motors and generators. HTS motors are significant for submarines because they are 3-4 times ROYAL AUSTRALIAN NAVY HMAS Collins puts to sea for fleet training. Her replacement is due in 2020, with greater endurance and speed. AviationWeek.com/dti APRIL 2008 DEFENSE TECHNOLOGY INTERNATIONAL 41 http://AviationWeek.com/dti
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