The boats cost R5.3 billion in 1999 and are built around a processor-rich combat management system (CMS) that allows the boat to “float, move and fight”.
The boats are SA's first true submarines, built to be more at home underwater than on the surface. The navy's previous French-built Daphne-class vessels were submersibles for which the reverse was true.
Unlike surface ships, where at least some of the crew can directly observe their environment, a submerged submarine is totally blind and utterly dependent on its sensors and the CMS's interpretation of the data gathered for even the most rudimentary of manoeuvres.
The Modjadji's builder says the boat will depart German waters in April and join her sisters at Simon's Town in May.
The CMS selected for the three South African submarines, the Manthatisi, Charlotte Maxeke and Queen Modjadji, is the German Atlas Elektronik Integrated Sensor Underwater System (ISUS) 90, a proven architecture designed for use onboard conventional submarines. The German company says 10 navies are currently using the ISUS 90, including that of SA and Germany.
Atlas Elektronik says the ISUS 90 forms the heart of the Combat Information Centre (CIC) from where the captain and his officers control every aspect of the vessel. “It ensures optimum support for the operator and command team alike. Sensor management, fire and weapon control, navigation and support functions are all implemented with a high degree of automatic control and comprise an advanced man-machine interface,” the company's Web site says.
ISUS incorporates data from a variety of acoustic, electronic and optronic sensors. “This information is then displayed in order to assist the crew with the detection, analysis, classification and tracking of… numerous targets,” the state arms agency Armscor's in-house journal said in a 2006 article.
The submarine's primary optronic sensor is an advanced Zeiss non-hull penetrating optronic mast, with improved bearing measurement and passive range finder accuracy, as well as optical clarity. The binocular eyepiece has built-in displays for bearing, range target height and periscope height above water. The mast – controlled from the ISUS console using a joystick – replaces the traditional second search or observation periscope.
The optical attack periscope mast has an integrated electronics warfare system and GPS antenna.
The submarine CIC is also fitted with a communications suite that enables the transmission and reception of signals across the radio frequency spectrum. It also enables communication with both the operational command, and the international maritime frequencies.
The boat's acoustic system is built around an Atlas 90-45 integrated sonar system consisting of a cylindrical hydrophone array, passive ranging sonar, intercept sonar, flank array sonar and own noise monitoring system (a mine detection system is optional). Then senior officer of submarines captain Malcolm Farre told reporters in April 2006 the flank array was new to the SA Navy and would take some years to fully master. He quoted a period of five to seven years. Its purpose is to detect acoustic transient noises in the lower acoustic frequencies.
Farre added that the Navy opted not to exercise an option for a towed array sonar (pulled behind the submarine). Other Type 209 operators had advised its capabilities were only marginally better than the flank array sonar, but at quite a price in cost and efficiency – as the system is clumsy.
Although largely fitted with German IT and electronics, the submarines do contain some local content. Cape-based C²I² Systems did some software work for the CMS “to allow for the integration of weapons and combat suite equipment selected specifically by the SA Navy, as well as the relevant human-machine interface software implementing the SA Navy's warfighting doctrine,” a 2001 press release says.
“The latter will be done in the Ada 95 software high-level language while the former will be done in C and C++.”
Tellumat Defence is another South African company involved in Project Wills, and manufactured and tested CMS consoles, electronic cabinets and printed wiring assemblies – known as the "dry-end" of the submarine CMS. DefenceTech, a division of the CSIR, supplied sonar hydrophones and transducers at the so-called "wet-end" of the CMS.
Also fitted is a Grintek Avitronics UME100 electronic warfare processor with omnidirectional radar warning receiver with integrated GPS antenna and an electronic emissions direction finding antenna fitted with a second integrated GPS antenna and an I-band surface search radar.
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