Suspicious buoy drop highlights Asian submarine tensions

Chinese People’s Liberation Army–Navy (PLA-N) ships earlier this week dropped a number of mysterious buoys around a group of islands in the East China Sea, and although Beijing says they are to monitor ocean conditions, suspicions abound.

The islands are the disputed string called Senkaku by Japan and Diaoyu by China and have for many years been the centre of an increasingly nationalistic tussle between the two powers.

Multiple military planes and ships belligerently traverse the area, inflaming tensions, but submarines have mainly been overlooked.

The buoys may really be for a scientific experiment, as Chinese foreign ministry officials claim, but it is more likely they are part of an expanding system of submarine detectors or sonobuoys China is using to monitor Japanese submarines.

Some were dropped just 300m from Japanese-controlled waters.

While surface tension and conflicts are featured in the news media, beneath the waves submarines are almost forgotten. 

Submarines more active

Submarine detection is difficult in the noisy and shallow waters typical of the South China Sea and the East China Sea. Acoustic energy from passive and active sonar technology is more likely to reflect off the seabed than in deeper waters, such as in the Philippine Sea.

Both countries have a number of different classes of submarines but the Chinese diesel-electric vessels are noisier than Japan’s more advanced similarly powered craft.

But the PLA-N’s newest Jin-class nuclear-powered ballistic missile submarines (SSBNs) are a mighty addition to Chinese undersea capabilities. While only two are assumed to be operational, and China is struggling with nuclear power at sea, they add serious firepower to its fleet.

And they may soon be equipped with JL-2 nuclear-tipped ballistic missiles, which, according to initial estimates, can reach the United States, meaning America's nuclear deterrence strategy would be undermined.

A submarine’s stealth makes it ideally suited for operating in restricted or sensitive waters, making them ideal for the tense waters around the Senkaku/ Diaoyu islands.

The reason for such tension becomes very clear on a map. Geographically, they occupy an extremely strategic position for both Japan and China.

They are a gateway for China into the greater Western Pacific. Controlling them would effectively allow the PLA-N to break out of the claustrophobic South China Sea, a result they desperately desire. 

Likewise, keeping them in Tokyo’s hands would help Japan pen China into their territorial waters and put a temporary lid on Beijing’s expansionist dreams.

Beijing's strategy

China’s development of a world-class submarine fleet is in its infancy, but even now Beijing can quietly project power a significant distance from its shores.

This is why the outcome of the Senkaku/Diaoyu islands dispute is so important for both nations. Controlling them would give Chinese submarines unfettered access to the Western Pacific and increase Beijing’s strategic options in the Eastern Pacific.

It would also open up the rest of the Pacific for exploration by its submarines, possibly sailing with nuclear-tipped ballistic missiles.

Only the US and Russia possess similar capabilities. Adding a third nation to the list will radically alter the strategic nuclear leverage America has enjoyed in the Pacific since the end of the Cold War.

Ultimately, Tokyo will not end its submarine patrols around the disputed islands, despite the Chinese sonobuoy drop. Submarines are an integral part of the monitoring of major sea routes to Japan.

With heightened military movements in the region the chance of an accident inceases. And with so much firepower in close proximity should the US become involved – along with widespread and popular nationalism in both Japan and China – the need to tread carefully to avoid escalating hostilities is paramount.