Australia extends combat system support for Collins-class submarines with Raytheon.

Australia’s Defence Department extended Raytheon Australia’s contract to sustain the Collins-class submarine combat system for three years and nine months, valued at more than A$270 million. The move preserves current fleet availability and aligns AN/BYG-1 software and hardware updates with the AUKUS Optimal Pathway to nuclear-powered boats.

Australia has renewed Raytheon Australia’s role as combat system manager for the Collins-class submarines, a three-year-and-nine-month extension worth more than A$270 million, according to Defence and company statements. Officials cast the decision as a continuity play, keeping AN/BYG-1 sustainment and upgrades on track while Australia builds toward SSN-AUKUS under the Optimal Pathway unveiled in March 2023.
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An Australian  Collins-Class submarine heading out to sea from Fleet Base West (Picture source: Australian MoD)

As integrator, Raytheon Australia continues the evolution of the Submarine Combat System AN/BYG-1, delivering software updates, hardware refreshes, and alongside support. The scope covers design assurance, deployable technical support, and spares. The Department of Defence oversees this work to preserve coherence between sensors, data links, and effectors while reducing interface risks. The combat system, designated AN/BYG-1(v)8, stems from an Armaments Cooperative Program (ACP) between the Australian and US navies and provides data fusion, fire control, and heavy-weapon management.

Designed for two-ocean surveillance requirements, the Collins class descends from five generations of submarines developed for the Swedish Navy. Among the first boats designed entirely with computer-aided tools, they feature an optimised hull, high levels of automation, low indiscretion rates, reinforced shock resistance, efficient weapons handling, and a design provision allowing integration of air-independent propulsion (AIP) if adopted in fleet policy. Based at HMAS Stirling in Western Australia, they remain a central element of national maritime defence.

Collins boats run silently on new-generation lead-acid batteries recharged by three onboard diesel generator sets. The Scylla sonar suite, with bow, flank, and towed arrays, feeds AN/BYG-1 for firing-solution computation and multi-track pursuit. Armament is centred on Mk 48 Mod 7 CBASS heavyweight torpedoes, employed through six 533 mm tubes, with a handling system designed to shorten reload times.

This architecture fits a systems-of-systems approach aimed at maintaining a Recognised Maritime Picture/Common Operating Picture (RMP/COP). The Royal Australian Navy seeks to manage concurrent software and hardware changes and to make verification, testing, and acceptance more reliable while preserving acoustic discretion. Strict Electromagnetic Emission Control (EMCON) governs snorkelling phases and energy management, while thermal layers exploited by the towed array improve long-range classification. In choke points and coastal waters, the combination of discretion, sensors, and torpedoes constrains adversary manoeuvre, whether surface groups or conventional submarines. In blue water, the Collins class conducts sea denial, undersea barrier operations, and intelligence tasks that contribute to the joint RMP/COP.

The industrial approach preserves Australia’s defence industrial and technological base (BITD). Keeping a single Australian prime for architecture, verification, and support helps manage offset and supply-chain risks. Continuity of AN/BYG-1 between Collins and future nuclear-powered platforms lowers requalification demands for fire-control and combat-system integration teams and supports interoperability with US and UK partners. Investment targeted at repeatable availability rather than headline technology leaps aims for practical operational effects: more predictable deployments, faster turnaround, and closer alignment between fleet performance and range-trial results.

The extension anchors continuity of Australia’s undersea presence during the transition to AUKUS. By maintaining a credible conventional fleet, Canberra narrows windows for coercion in the Indo-Pacific, secures sea lines of communication to the Indian Ocean and through Southeast Asian straits, and supports allied posture by contributing to a shared RMP/COP. Convergence around AN/BYG-1, higher interoperability with US and UK navies, and consolidation of the local BITD create momentum: crews, test chains, and combat-system integrators already work on building blocks intended for the future SSN-AUKUS fleet. This capability and industrial coherence help stabilise regional risk calculations pending the arrival of the first nuclear-powered units.