Attack submarines are arguably the decisive weapons in high-intensity warfare between foes separated by oceans. Mobile, stealthy and heavily armed, they can sink invasion flotillas, bottle up enemy combat fleets, cut supply lines and strangle economies by throttling trade.
And that’s why the dire condition of the submarines in some of the most important free countries is so troubling. The United States, the United Kingdom and Australia are all struggling to maintain their attack boats at precisely the same moment they most need the boats to deter China.
The Australian sub fleet is the most recent to descend into crisis. According to the Australian Broadcasting Corporation, just one of the Australian navy’s six Collins-class subs is fit for combat. The other three are “beset by problems” including corrosion, ABC reported.
Australia plans to replace the 1990s-vintage, diesel-electric Collins with second-hand nuclear-powered boats from the United States starting in the 2030s. New nuclear subs built under the auspices of the AUKUS alliance between Australia, the United Kingdom and the United States would later replace the used vessels.
Nuclear-powered subs present a hugely greater threat than conventional ones, as they can move fast and far while fully submerged. A diesel sub can only go fast and far fully surfaced, and needs to put up a “snort” air-intake mast for long periods at regular intervals to charge batteries when submerged. This places the sub in great danger when operating in an area covered by enemy radar, and a single maritime patrol plane can scan hundreds of miles of sea.
So the new nuclear boats will make the Australian navy a lot more dangerous. But the 3,500-ton Collins class are Australia’s only manned undersea capability for the next six years, if not longer. And while a new class of small robotic sub might complement the Collins, such vessels lack the heavy weaponry – Mark 48 torpedoes and Harpoon anti-ship missiles – that lend the manned subs their punch.
A 2023 war game organised by the Center for Strategic and International Studies in Washington DC underscored what many observers have long assumed – that submarines could be the main line of defence between China and Taiwan in the event the Chinese Communist Party ever makes good on decades of threats and attacks the island democracy.
In that war game, US Navy nuclear attack boats sailing from Guam sank scores of Chinese transports and warships, ultimately defeating the invasion attempt – albeit at the cost of a fifth of the subs. If the US, Australian, British and Japanese fleets – and the Taiwanese fleet, of course – could muster most of their subs, they could present a powerful united front to the Chinese fleet. The nuclear boats could move in to attack Chinese vessels in the Taiwan Strait without worrying overmuch about Chinese air and missile power, and conventional ones might sneak in slowly and carefully
But at present, Taiwan’s friends by and large can’t muster most of their boats. As recently as a year ago, just 60 per cent of the US Navy’s roughly 50 attack subs were ready for combat – significantly short of the Americans’ 80 per cent readiness goal. The Royal Navy has six nuclear attack boats, and plans to base one of them in Australia from 2027. But more than once in recent years, there have been zero British boats at sea.
If there’s a silver lining in this maintenance storm, it’s that the powerful Japanese sub flotilla – 24 diesel-electric attack boats – is in good shape. The Taiwanese navy’s two 1980s-vintage diesel-electric attack boats are also in reasonably good condition. But they couldn’t make much of an impact on their own in wartime, and it could be more than a decade before Taipei acquires all eight new subs it has planned.
Overall, the Western allied undersea fleet is in trouble. There are lots of subs, but too many of them are too old or worn out. It might take scores of submarines to defeat China at sea. Can the allies sail enough subs on short notice – and keep them in action long enough to win a war?
It’s hard to say. But it’s telling that Admiral Lisa Franchetti, the US Navy’s top officer, has prioritised the maintenance of existing ships over the construction of new ones. “We will continue to prioritise readiness, capability and capacity – in that order,” she wrote, tacitly acknowledging that the US fleet has a maintenance problem, and needs to solve it immediately.
That’s easier said than done, and not just for the Americans. The industrial side effects of the Covid pandemic, challenges associated with maintaining any skilled workforce, budgetary constraints and the overall advanced age of Western submarines owing to the “peace dividend” of the 1990s – during which many democracies built very few new subs – represent huge hurdles to near-term readiness.
Allied navies need to get their attack boats in shape. Whether they can, and how quickly, could mean the difference between victory and defeat in any coming Pacific war.
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The free world’s most potent weapons against China have been crippled