Soundings in the Dark

From Gwadar to Mauritius, China’s ‘research’ ships are forcing a reckoning with India in the Indian Ocean.

Recently, satellite and AIS data revealed the familiar choreography of four Chinese ‘research’ ships - Lan Hai 101, Lan Hai 201, Shen Hai Yi Hao and Shi Yan 6 - fanning out across waters that India and its partners consider strategically intimate. While Beijing insisted these were benign scientific missions, the hardware bolted to their decks suggests otherwise.

The missions were in fact a slow, methodical mapping of the underwater battlespace around India’s maritime periphery. Seabed contours, salinity layers, thermal gradients and acoustic signatures are the currency of modern naval power. They guide submarines, shape anti-submarine warfare and refine missile-tracking algorithms. Whoever owns such data owns the advantage of invisibility.

Oceanographic Archive

Lan Hai 101 was tracked on November 28 heading towards Galle in Sri Lanka, a port that continues to host Chinese research vessels under replenishment arrangements. The waters near Sri Lanka sit astride India’s eastern naval approaches, already among the most closely monitored in Asia. Each port call thickens China’s growing oceanographic archive.

Lan Hai 201 has been engaged in repeated grid-like movements near Diego Garcia, the American military base that anchors the Western alliance’s Indian Ocean presence. Such patterns are the signature of detailed seabed mapping that are useful for academics, invaluable for submariners plotting stealthy routes beneath the thermocline.

Shen Hai Yi Hao, one of China’s crown jewels of underwater exploration, is equipped with a manned deep-sea submersible. Officially spotted west of Indonesia on November 24, its projected track pointed towards the central Indian Ocean. High-precision sampling and underwater inspection blur the line between science and submarine support with remarkable ease.

Meanwhile, Shi Yan 6 was seen steaming towards Port Louis, Mauritius. Ships of its class routinely collect magnetic, seismic and acoustic data - essential inputs not only for marine research but for future submarine deployments and anti-submarine modelling.

None of these vessels flies the colours of the People’s Liberation Army Navy. That distinction fools no one. India and other maritime powers now track Chinese survey ships with the same intensity they devote to warships.

The timing of the operation of these ships is a matter of concern. Their latest dispersal coincided with India’s issuance of a NOTAM declaring a vast no-fly zone of nearly 3,500 kilometres off the coast of Visakhapatnam, home to India’s Eastern Naval Command and its nuclear submarines. The airspace restriction bore the unmistakable signature of a long-range ballistic missile test, likely linked to the K-series sea-launched programme.

This is too familiar a coincidence. In the past, Chinese tracking vessels - from the Yuan Wang fleet to specialised survey ships - have loitered near Indian missile-test corridors with suspicious punctuality.

Undersea Dominance

China’s use of ‘scientific’ platforms for strategic maritime reconnaissance is not a novelty of the Xi Jinping era. As far back as the 1970s, under Mao, Beijing treated oceanography as an instrument of national power, laying the intellectual foundations for what would later become its undersea dominance strategy. The pattern became unmistakable after 2008, when Chinese survey ships began appearing regularly in the Bay of Bengal following India’s Agni missile tests. In 2014, the dual-use fiction collapsed entirely when a Chinese attack submarine docked in Colombo under the guise of an anti-piracy deployment - an episode that jolted New Delhi into recognising how seamlessly science, commerce and coercion now blend in China’s maritime statecraft.

Hambantota’s 99-year lease, Gwadar’s militarisation, Kyaukpyu’s deep-water access and the steady normalisation of Chinese port calls across the Indian Ocean have supplied Beijing with the logistical skeleton its survey fleet now flesh out with data. What satellites record today is merely the visible edge of an accumulation that has been under way for nearly two decades.

From Sri Lanka to Diego Garcia, from Mauritius to Southeast Asia’s maritime gateways, the four ships now sketch a quiet quadrilateral of Chinese presence in the Indian Ocean. Individually, each mission looks harmless. Collectively, they amount to an expanding hydrographic shadow around India’s neighbourhood.

What unsettles Indian planners most is the cumulative logic of these deployments. China is quite methodically constructing a living ‘oceanographic library’ of the Indian Ocean that will only grow richer with every so-called survey mission. From acoustic fingerprints of the seabed to temperature layers that bend sonar, this invisible data will outlast ships and outlive political thaws. The recent easing of tensions along the Line of Actual Control does little to dilute the hard reality at sea which is that maritime power is built in peacetime, not crisis.

Indian security agencies today treat Chinese ‘research’ missions as part of a broader pre-positioning strategy, tied to Beijing’s growing access to ports from Gwadar and Hambantota to Kyaukpyu and now, more tentatively, to footholds in Mauritius and the Maldives. Yet awareness is not the same as readiness. India’s submarine numbers remain thin, its construction timelines are slow and its undersea deterrent still a work in progress.

Sun Tzu warned that war is “a matter of life and death, a road either to safety or to ruin.” In the Indian Ocean today, that road is being quietly surveyed by Chinese ships that insist they are merely studying the sea. India would be wise to study them just as closely.

(The author is a retired Naval Aviation Officer and a defence and geopolitical analyst. Views personal.)