Major differences between French submarines American-British submarines

Australia canceled a significant submarine contract with France worth $90 billion last month, choosing instead to work with the United States and the United Kingdom.

Australia’s decision to rip up its $90 billion agreement with France for 12 diesel-powered submarines, and opt instead to build nuclear-powered vessels with Britain and the US, is a landmark moment for Asia-Pacific geopolitics and the global defence industry.

The new submarines will be much more capable than the original planned fleet, and could mean a bonanza for defence contractors in the UK and America.

Propulsion: diesel vs nuclear

The key difference between the French-built and the proposed new submarines is the propulsion technology they will use. The vessels from France – based on that country’s own nuclear-powered Barracuda class – were to have had electric motors charged by diesel engines.

One of the advantages is that diesel-electric submarines tend to be smaller and can be run silently by turning off the diesel motor and relying on battery power. A disadvantage, however, is that the boats need to resurface regularly to run their diesel engines so that the batteries can be recharged – an operation known as “snorting”.

Royal navy nuclear submarine
Royal navy nuclear powered submarine

Nuclear-powered submarines, on the other hand, are built for endurance. They have a reactor that generates electricity that powers electric motors and drives the propeller; alternatively, heat from the reactor is used to create steam that turns the turbines.

Australia originally opted for diesel-electric submarines to replace its own fleet of conventionally powered Collins-class boats.

Defending Australia’s decision this week, Scott Morrison, Australia’s prime minister, said he had told French president Emmanuel Macron in June there were “very real issues about whether a conventional submarine capability” would address Australia’s strategic security needs in the Indo-Pacific. French officials say Paris offered that month to convert the submarines into nuclear-powered ones as it has the technology but was met with silence.

Opting to go down the nuclear route, however, will not be without its challenges given Australia’s lack of critical infrastructure.

“The whole nuclear infrastructure you need is very expensive – the people, the safety arrangements and the docking facilities, just to name a few,” said Trevor Taylor from the UK’s Royal United Services Institute, a think tank.

Stealth and detection

The biggest benefit of nuclear-powered submarines is that they can stay submerged and remain stealthier for much longer. Conventionally powered vessels do not have the same range without exposing themselves to detection by coming to the surface. Nuclear-powered submarines can carry enough fuel for up to 30 years of operation and only need to return to port for maintenance and supplies.

US Navy Ohio class nuclear powered subamrine
US Navy Ohio class nuclear powered subamrine

Nuclear-powered submarines are the “most complex machines that humans make, even more so than the space shuttle”, according to one defence expert. “You have a nuclear reactor at the back, high explosives at the front and in the middle, a hotel, where people live, and the whole thing goes underwater for months at a time.”

It is not yet clear what type of design Canberra will choose. However, it is likely to be based either on Britain’s Astute submarines, built by BAE Systems, or the US navy’s equivalent, the Virginia class, built by America’s General Dynamics Electric Boat and Newport News Shipbuilding.

One of the key questions will be how much of the silent running and sonar technology of their fleets the British and Americans are going to give the Australians.

Weapons capability

Australia will also boost its weapons capabilities significantly under the tripartite agreement.

Richard Fontaine, head of the Centre for a New American Security, said Australia would deploy conventional missiles on the submarines, which had larger payloads than the weapons that would have been on the French vessels.

The decision to acquire Tomahawk missiles – which can be fired from either ships or submarines – also marks a major addition to Australia’s capabilities.

Tomahawks transform a surface navy ship into a strategic asset that can target military facilities ashore from a thousand miles away. This new payload will significantly upgrade the conventional strike power of the Australian navy,” said Eric Sayers, a defence expert at the American Enterprise Institute.

Sayers said the move continued the trend of Canberra adopting common munitions with the US, including anti-ship weapons such as the MK48 torpedo and the LRASM, a missile that can be launched from an F18 fighter jet.


French navy Barracuda-class nuclear attack submarine
French navy Barracuda-class nuclear attack submarine

The Tomahawks would give Australia more capability to hit targets in China in any conflict, which is important because the US and its allies would have fewer military assets off the coast of China than the Chinese military.

“The Tomahawk opens the door to long-range strikes against land targets like taking down integrated air and missile-defence systems or aircraft hangars,” Sayers said.

Who will build them?

British prime minister Boris Johnson may have talked up the potential impact on UK industry but defence executives said it is too early to say what the agreement could mean for the country’s contractors. Nevertheless, there should be some benefits.

Sash Tusa, analyst at Agency Partners, said a “$50 billion-plus defence equipment programme, even spread over, say, 20 years, should produce some winners, especially given how tied Australia becomes to the US and UK. It has no nuclear industry of its own, and so will require many decades of heavy support, including direct supplies of nuclear fuel.”

BAE, which builds submarines for the Royal Navy at its Barrow-in-Furness site in Cumbria, northwest England, is seen to be in prime position. The company is already building a version of its Type-26 frigates for the Australians at a new shipyard in Adelaide. Rolls-Royce, which provides the propulsion systems for Britain’s submarines, could build reactors for Australia’s fleet.

Rusi’s Taylor points out that despite Britain’s own problems with the Astute programme, which was hampered by delays and rising costs at the start, the submarines are cheaper than their US counterparts.

Duration of construction

Australia’s Morrison said this week he expected the first nuclear subs to be built in Adelaide by 2040. A lot can still go wrong; the construction of submarines is a mammoth undertaking and most programmes are notorious for being late and over-budget.

Britain’s new Astute submarines may be cutting-edge but their procurement is a sobering reminder that things will take longer – and cost more – than originally expected. – Copyright The Financial Times Limited 2021

Source: irishtimes

Leave a comment

Your email address will not be published. Required fields are marked *