How many submarines? (part 1)
8 Jan 2014|

Vision of HMAS Farncomb sitting on the sea floor is relayed back to the ROV (Remotely Operated Vehicle) control module onboard ADV Ocean Shield during Ex Black Carillon 2013.

In my earlier post ‘Why submarines for Australia?’ I flagged the Chief of Navy’s emphasis on criticality of the maritime environment for Australia’s prosperity, the impact of growing regional maritime power, need to look for capabilities that will give future Australian Governments’ options to cope in this emerging situation and hence the requirement for long range, long endurance, survivable submarines.

I take this as the starting point for this discussion of how many submarines Australia needs, to provide sufficient ‘strategic impact’ to make a potential aggressor avoid a military confrontation with Australia, given the ‘interesting’ strategic circumstances ahead of us.

It’s worth re-iterating that the submarine’s most fundamental, key feature is its stealth. Given this attribute, a well-handled submarine is able to operate without causing fuss in areas where sea and air control isn’t assured, and to gain access to areas denied to other platforms. Large submarines, such as Collins, are able to operate at long range for weeks, carrying a flexible payload of sensors, weapons and specialist personnel. A capable submarine force is probably our most potent anti-submarine weapon system, perhaps their most demanding role. A potent submarine capability creates great uncertainty for an adversary: countering them is difficult, expensive and can’t be guaranteed.

Given the unfolding strategic landscape, my starting assumption is that our submarine force must be capable of operating and surviving north of the archipelago, throughout the South China Sea, able to observe, report and if necessary strike. As I argued in my post almost a year ago, this is the high payoff area, where their impact is greatest and unique amongst ADF assets.

To be able to exploit the initiative gained from their stealth, Australia’s submarines must be able to covertly reach sensitive areas throughout our region with sufficient mobility, endurance and payload for the long duration missions involved, frequently in or through demanding tropical waters.

Against this setting how many submarines does Australia require? Before turning to the number crunching I’ll make two points based on practical observation that are unlikely to change for the next generation submarine.

The first is the ‘rule of three’. Like aircraft and helicopters, submarines operate under a strict maintenance regime, and are designed to provide a high level of serviceability at sea and to avoid catastrophic failure of a key system (and in the worst case, loss of the submarine). Given sufficient qualified personnel, this regime determines submarine availability; from three submarines, typically one will be in maintenance/refit, one will be training/preparing for a deployment and one will be available for deployment or deployed. Submarines come in threes.

The second observation is that a force of six submarines, ie typically with three or four available or at sea (under the rule of three) will struggle to achieve sufficient sea days to generate enough of the highly skilled/long training time personnel such as commanding officers, engineers and senior technicians to man the four to five crews and provide the essential shore supervisory staff in the Submarine Squadron and policy areas. In support of this contention I’d cite the perennial shortages in these categories across the Oberon and now the Collins submarine force for the 40+ years I’ve been working in or observing it.

My modelling of these training pipelines demonstrates that a force of at least nine submarines, ie typically six at sea is the minimum to achieve a sustainable critical mass of specialist/experienced personnel. The RAN has survived hitherto by lateral recruiting qualified personnel from other navies—not a reliable basis for manning a core capability.

Turning to the maths, this calculation starts with the requirement. Geography is a major factor; it’s 2,900–3,000 nautical miles from HMAS Stirling in Perth to the southern end of the South China Sea via the three to five choke points on a typical transit route for a conventional submarine. Without being specific about the scenario, it’s therefore likely that Australia will wish to be capable of maintaining a deterrent submarine presence at very long ranges, say 3,500 nm.

For practical deterrence I suggest that Australia should be able to sustain at least two submarines in this area, to offset the risk that a single submarine could be effectively neutralised as a deterrent by its mobility restrictions in the event of counter-detection by adversary forces. This would provide maximum strategic effect at lower risk. Concurrently, Australia would also wish to provide submarines closer to home in support of Task Force operations, for special force missions or training own ASW units.

The issue of concurrent roles and an allowance for attrition of own submarines employed on offensive operations are additional factors to the calculation of the force structure required to achieve the strategic effects. So how many submarines does Australia require for a strategic impact given this geography? Tomorrow I’ll finish off this simple estimate by bringing in some practicalities of submarine design.

Peter Briggs is a retired RAN submarine commanding officer and past President of the Submarine Institute of Australia. Image courtesy of Department of Defence.