The science of stealth
Making the world’s quietest ASW frigate
The Global Combat Ship - Australia (GCS-A) will be a refined design of the UK Royal Navy’s Type 26 Global Combat Ship, a vessel designed specifically for Anti-Submarine Warfare (ASW), and designed and built by BAE Systems.
The Type 26 Global Combat Ship’s (Type 26) hull form and propulsion system operates with an exceptionally low underwater-radiated noise, thereby providing the best possible platform to detect and avoid detection in the theatre of submarine
When compared to the mechanical power and propulsion systems of the ANZAC class frigate, a hybrid-powered Type 26 will have significantly reduced underwater radiated noise contributing to a significantly enhanced ASW performance.
In excess of 5,000 work years of engineering design have gone into developing the Royal Navy’s Type 26 which will be the world’s most potent ASW platform.
A range of engineering design features will contribute to making the Type 26 the quietest ASW vessel in the world. These include optimizing the hull form for low noise during high-end ASW operations, and addressing the power and propulsion
system which is traditionally a significant contributor to underwater radiated noise.
"By 2030, it is expected that half of the world’s submarines will be in Australia’s broader strategic region. A high-end ASW capability will be required to combat these threats."
The Type 26 will feature a hybrid power and propulsion system which aims to improve underwater radiated noise performance in a number of ways:
- The propulsion system is a combination of electric and mechanical propulsion drive, made possible by the most power dense gas turbine (GT) in the world, Rolls-Royce’s MT30 engine. The MT30 is proven at sea, having been in-service
since 2008. Producing 36MW of power at 38ºC, the MT30 will take the vessel to full speed in a matter of minutes and release the ship’s electrical generation capacity to the ship’s weapon systems.
- When at cruising speed or engaged in submarine operations, the ship relies on four Rolls-Royce MTU diesel generators to power its shaft-wound main motors, thereby eliminating main gearbox noise. In this ultra-quiet diesel electric propulsion
configuration, BAE Systems’ Type 26 will out perform the noise signature of the UK T23 Frigate, the ‘ghost ship’, widely recognised as the benchmark for ASW capability and low underwater-radiated noise signature.
- Electric motors enable the use of fixed-pitch propellers which, when compared to controllable pitch propellers typically used on mechanical systems, can be quieter from a hydrodynamic perspective.
- Since the majority of submarine hunting operations are performed at 9-12 knots, a hybrid platform will run on the electric motors whilst de-clutched from the gearbox. This removes the gear meshing noise as well as noise from the gearbox’s
auxiliary systems (eg: the cooling system) that would normally emanate from a mechanical platform running on main propulsion diesels.
- Power for the electric motors is provided by enclosed and resiliently mounted diesel generators. At such a low speed and thus power requirement, it is foreseeable that only two diesel generators would be required during ASW and these could
be physically located higher in the ship to reduce underwater radiated noise. This was the approach that was used by the Royal Navy on the Type 23 and will be used on the Type 26 which started production in the UK earlier this year.
"The MT30 will take the vessel to full speed in a matter of minutes and release the ship’s electrical generation capacity to the ship’s weapon systems."
By 2030, it is expected that half of the world’s submarines will be in Australia’s broader strategic region and so a high-end ASW capability will be required to combat these threats. The Federal Government could look to leverage
its partner Navies’ investments and capabilities in ASW and to establish itself at the forefront of developing the next generation of ASW.
To address a broader range of threats, including missile defence, the Federal Government recently announced that the Future Frigates will be equipped with the AEGIS combat system. As a new and fully digital design, the GCS-A has substantial
growth margin to ensure a seamless integration of AEGIS without compromise to its ASW capability.
Rolls-Royce has been actively working with South Australian industry and Government to identify and engage with local South Australian companies for the manufacture of Rolls-Royce products for the GCS-A.
This includes the MT30 gas turbine enclosure and auxiliary systems, stabilisers and steering gear, propellers, mission bay handling equipment and moveable high points to enable replenishment at sea.
If BAE Systems is successful in its bid for SEA 5000, South Australian companies selected to manufacture products for the GCS-A will join the Rolls-Royce supply chain helping to ensure a sovereign support capability for the vessel, through
life maintenance requirements and opening up export opportunities.
South Australian companies have previously been engaged with Rolls-Royce technology for manufacture of the stabilisers for the ANZAC Class Frigate fleet and the largest ship lift in the Southern Hemisphere at the Osbourne Ship Building Facility,