Building on its long history ^[1] as a forward operating base, Darwin is ready to support our future submarine operations. Though it’s commonly seen as unsuitable as a home port for submarines, that doesn’t disqualify Darwin from playing a logistic support role to resupply and maintain the boats mid-patrol and rotate out their crew.

A 2016 report ^[2] by the Defence Science and Technology Group contended, ‘The shallowness of the surrounding sea near Darwin that leaves submarines vulnerable to attack, the location of the city on Australia’s northern frontier closest to potential adversaries and the relative lack of industrial infrastructure make Darwin less than idea[l] as a submarine base.’ Let’s consider each point.

In the first instance, it’s hard to argue with geography.

It’s true that the Timor Sea is shallow at an average depth of 200 metres, compared with the 300 to 450 metres at which most submarines operate. Meanwhile, the Arafura Sea is even shallower with a depth of between 50 and 80 metres. That’s just enough for a Kilo-class submarine—with a reported minimum depth requirement of 45 metres—not to scrape the seabed.

On these grounds, some observers have expressed concerns ^[3] about our submarines losing the stealth central to their deterrent effect. But submarine rotations to Darwin present an acceptable level of risk to train submariners to defend our approaches and surface combatants, as they might need to do in wartime.

A second concern is premised on Darwin’s proximity to the front in the Pacific War.

A 2011 Department of Defence report ^[4] on future submarine basing options stated that Darwin wasn’t assessed partly because, as ‘Australia’s northern most capital city, it is believed to be inherently more vulnerable to hostile attack than any other city’. This would make chilling reading for people in Darwin who haven’t forgotten repeated air raids during World War II on our city, but we should reflect dispassionately on what it means for our national defence.

If Darwin was ever in such a dire situation again, contemporary weapons systems could likely bring Fleet Base West and all of our bases north of Tasmania within range. In today’s world, an enemy no longer needs to be at the gates to attack our cities, northern or southern. Geography is therefore a flimsy reason for not rotating submarines in Darwin.

Current strategic trends are increasing the value of Darwin as a forward operating base. If our cities were being targeted by long-range weapons, without intermediate-range missiles of our own and with our F-111s retired, the Attack-class submarine could present the most potent and maybe only means to counter attempted coercion. In this scenario, 10 days’ extra fuel could be tactically decisive in our ability to sustain a submarine forward presence to defeat a long-range threat.

Finally, let’s consider our local defence industry.

Some have argued that Darwin Harbour is inadequate for our future submarines because there’s only one entrance. But with the exception of Fleet Base West, all options assessed in the 2011 report—Sydney, Jervis Bay, Newcastle and Brisbane—also have only one entrance. What some ports gain in strategic depth they lose by being a very long way from anywhere our submarines might need to patrol or loiter.

It’s true that Darwin still lacks the skilled workforce to sustain submarine operations. Learning from our Collins-class recruitment woes, it makes eminent strategic sense to homeport future submarines on the densely populated east coast. For the foreseeable future, Darwin won’t contest the place of other larger cities in supporting our submarine industry.

Darwin’s comparative advantage is to serve as a forward operating base—a role which other capitals don’t want and can’t play. Darwin has solid logistical, airport and housing infrastructure to sustain a skilled local workforce to perform light maintenance, leaving the much trickier and longer full-cycle docking in South Australia or Western Australia.

In this connection, I salute the announcement by Rear Admiral Wendy Malcolm at the Pacific 2019 exposition in Sydney this month that Defence was moving towards a new model of regional maintenance centres in Darwin, Cairns, Perth and Sydney. Her presentation to industry confirmed that Darwin was considered important to sustain the navy’s operations, which will require a skilled local workforce rather than one working on a fly-in, fly-out basis. This will make it even more operationally attractive to rotate future submarines through Darwin.

Currently, when submarines visit Darwin from being ‘up top’, they tie up to the submarine buoy in the middle of Darwin Harbour. They’re not there for long, taking about a day to resupply. Ongoing redevelopment of facilities at HMAS Coonawarra to build a wharf structure and berthing dolphins will allow our future submarines to be even more quickly and effectively refuelled and resupplied. But we can do much more.

The 2011 Defence Department report concluded that ‘Darwin as a forward operating base for FSM [future submarine] operations will enhance FSM capabilities.’ One obvious way in which this will be true is the added range and presence Darwin will give our submarine operations. Diesel-electric submarines need more pit stops than their nuclear-powered cousins, making Darwin vital to any extension of their operational range. The upcoming strategic review of the 2016 defence white paper should explicitly note Darwin’s value in this regard.

Finally, Darwin’s enhanced profile as one of the navy’s key regional maintenance centres won’t be of use to just our own forces. Some speculate ^[5] that Darwin could in future accommodate ships as large as a Nimitz-class aircraft carrier.

If that’s true, we’ll see more than Australian submarines frequenting Darwin to protect these high-value assets. And we’ll also need to step up our inbound port visits and naval exercises with Indonesia and other ASEAN partners for Darwin to continue to play its role as a crown jewel of our defence diplomacy.