What should Australian submarines do? – Response to Brian Toohey

Oct 21, 2020

Brian Toohey’s challenging post (19 October) concerns what we want our submarines to do. In light of the recent Defence Strategic Update, the ADF needs to build a force capable of deterring an attack by a major power.

Because of a submarine’s stealth and ability to act as a force multiplier, it is probably the most important military asset in an ADF structured around deterrence. This is particularly the case where a middle power like Australia needs assets that best provide the wherewithal to deliver an asymmetric strategy for countering the potential ambitions of a great power like China.

Contemporary naval doctrine suggests a submarine’s deterrent effect will be best realised if it operates in an offensive role ‘up threat’. This doctrine is reflected in the Commander of the US Submarine Force’s statement of the role of the nuclear-powered submarines under his command: “to hold the adversary’s strategic assets at risk from the undersea — their homeland, SSBNs on patrol, carriers, critical undersea infrastructure, cyberspace, strategic ports and chokepoints, and submarines”.

The Force Commander has also revealed that the US has concluded a protocol with Australia whereby the two countries work together in anti-submarine warfare (ASW) operations. It seems clear these would occur in and around the South China Sea. So we can conclude that Australian submarines work together with their American counterparts to detect and track the PLA Navy’s submarines and, no doubt, other naval assets as well. They could only do this with access to America’s extensive and highly expensive command, control, communications and intelligence (C3I) system. The RAN’s role is likely to be similar in many ways to that of the Royal Navy in the North Atlantic during the Cold War. Like the RN, we can also assume that, for reasons of sovereignty, the RAN would retain operational control over Australian submarines, which would be subject to very carefully defined rules of engagement.

A major difference is that on these missions Australia deploys conventionally powered submarines, which the British withdrew from front line operations against the Soviet Union forty years ago. This means that with a six submarine force and a distance of 3,500 nautical miles to our primary area of operations, we can maintain one submarine on station for only half the time. Although they still have some advantages in terms of their acoustic signature, which are reducing over time as SSNs become ever quieter, conventional submarines are particularly vulnerable because of both their periodic need to snort and their low sustainable speed.

Toohey says these joint operations are dangerous, which they are, and are becoming increasingly so as ASW detection technologies improve and the PLA Navy invests in more and more assets that deploy them. Perhaps the greatest danger, however, is if the strategic objectives of the US and Australia diverge and a RAN submarine was on station when, by accident or design, a kinetic event developed in the South China Sea and triggered a wider conflict between the PRC and America. If the Australian government had no intention of going to war, could we withdraw from such a conflict in time and detach our force in good order?

Toohey’s solution is for Australian submarines to operate around the archipelagic chokepoints in a defensive posture, presumably to intercept a hostile fleet on its way to attack Australia. This is problematic for a number of reasons. First, we would need a lot of submarines – Hugh White says between 24 and 32 – to cover all the possible chokepoints. (Q: If it takes us 40 years to acquire 12 submarines, how long would it take to procure 32? How long would it take to recruit the required number of submariners?) Secondly, the enemy may not come through the chokepoints at all. They may instead stand a long way off and attack Australia with long-range bombers or missiles. Thirdly, if the enemy deployed nuclear-powered submarines to the chokepoints in advance of a planned attack, they could loiter around and sink our conventional boats on patrol when they came up to snort.

But the main reason that Toohey’s solution is unconvincing is that submarines, particularly conventional submarines, have never performed well in delivering a defensive strategy. For example, there were 40 German U-boats – seven of them with the latest snorkel equipment – deployed to attack the Allied invasion fleet in June 1944 and their failure was comprehensive. Yet the size of the theatre off Normandy was far smaller than the one we are considering to the north and west of Australia.

But I certainly agree that the timetable for deploying the Attack class is totally inadequate and the capability eventually to be delivered not cost-effective. For an outlay of $90bn, we will be waiting for over thirty years before we can guarantee that one slow and vulnerable submarine will be on station in its primary area of operations at any time. Since the submarine would be highly vulnerable, we would also have to reckon on a material level of attrition. Whether the Attack class would be fit for purpose in terms of both effectiveness and survivability is therefore open to serious doubt.

The inconvenient truth is that if Australia wants to operate submarines so as to deter any potential adversary in the future, not just China, they will need to be nuclear-powered, each with a capacity to deploy several Un-crewed Underwater Vehicles (UUVs). Even in the event the Americans do go home, the deterrent effect of our submarines will be maximised if they continue to operate in an offensive role ‘up threat’ and, in line with US doctrine, “penetrate adversary defensive perimeters to deny safe haven, reduce defences, and exploit opportunities created by being inside their fence line”.

It would be handy if the Americans left their C3I infrastructure in place if they withdraw, but Australia may be able to re-create some of its essential elements. A nuclear-powered submarine force could also develop more flexible operational strategies by taking advantage of their greater speed and evolving new technologies, such as autonomous vehicles and cyber.

For example, if Australia deployed nuclear-powered submarines in the absence of US support, they could operate ‘up threat’ by standing further out to sea than may currently be the case and deploying UUVs for destructive operations closer inshore. In addition, their speed and lethality would also offer other avenues to denying an adversary access to our approaches in and beyond the air-sea gap – avenues that would not be available to a conventional submarine because of its limited speed and vulnerability. If necessary, for instance, Australian SSNs could rapidly execute an offensive chokepoint strategy by re-deploying to waters further north in the approaches to the archipelago.


Jon Stanford gratefully acknowledges the contribution to this post of Submarines for Australia and comments by members of its reference group.

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