In the contested waters of the Indo-Pacific, strategic power is increasingly being shaped not by the aggressive manoeuvring of warships, but by the quiet, deliberate movement of survey vessels. In the South China Sea, China’s hydrographic expeditions are mapping every contour and feature of the seabed, driving Beijing’s expansive maritime claims in contested waters. In places like Spratlys Islands and Paracel Islands, data gathered through seabed surveys drives Beijing’s legal claims to sovereignty — claims that bolster strategic infrastructure development and enable the precise deployment of naval and paramilitary forces. The message is clear: whoever maps the sea, masters it.
China’s survey ambitions are no longer confined to the Pacific. Its research and hydrographic vessels have been sighted with increasing frequency in the Indian Ocean — off the coasts of Sri Lanka, the Maldives, and even Myanmar. Last month, a French maritime intelligence firm flagged a Chinese research vessel operating in the Bay of Bengal, raising concerns in New Delhi. Ostensibly conducting scientific research, such vessels are widely known to be collecting bathymetric data in strategic channels and exclusive economic zones where China holds no sovereign stake. For regional navies, the pattern is hard to ignore: hydrography is no longer a benign, technocratic pursuit for China. It is, in fact, an enabler of maritime influence, a precursor to a wider strategic presence.
Strategic utility of maritime survey
China’s growing deployment of survey vessels in the Indian Ocean underscores a reality long evident to naval practitioners, but only recently acknowledged in the wider strategic discourse: hydrography is geopolitical currency. It provides the means to assert maritime jurisdiction, to enable safe navigation, and — crucially — to shape the legal and physical architecture of maritime space. In a maritime environment increasingly defined by low-end competition and grey-zone operations, the ability to chart waters and build marine capacity is increasingly vital to influence-building.
China’s maritime activism has been noted in India, whose own approach rests on very different foundations. Where Beijing’s maritime forays raise concerns of covert surveillance and unilateralism, New Delhi’s outreach is shaped by transparency, partnership, and a deepening of trust. Over the past two decades, India has leveraged its hydrographic and meteorological expertise to become a sought-after partner in the Indian Ocean Region (IOR) — not through the assertion of hard power, but by enabling littoral states to unlock their maritime potential.
Mauritius offers a compelling case in point. With India’s assistance, the island nation recently completed a hydrographic survey of more than 25,000 square nautical miles — a quiet but consequential step toward strengthening maritime infrastructure, planning coastal development, and managing marine resources sustainably. Indian survey ships have also undertaken multiple missions in the waters of Seychelles, covering key areas around the nation’s three main islands: Mahé, La Digue, and Praslin. Under a 2015 MoU, India provided hydrographic data, training, and chart-making support, which culminated in a 2020 survey whose updated nautical charts are now helping drive Victoria’s blue economy initiatives. In the Maldives, too, Indian hydrographic ships were active in mapping regional seas until the current administration blocked the renewal of a pact for joint surveys. Crucially, for New Delhi, collaborative efforts with Sri Lanka are helping define fishing zones, easing maritime tensions, and promoting shared stewardship of the seas.
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India’s hydrography endeavours
At the heart of India’s cartographic diplomacy is the Indian Navy’s hydrographic department — an arm that has rarely drawn headlines but has steadily worked to extend India’s influence. Naval survey ships, operating across the waters of the Indian subcontinent and the east coast of Africa, have carried out precision mapping of littoral zones, handing over modern, navigable charts to partner nations. Crucially, they have done so without triggering the anxieties that often accompany the presence of foreign vessels. There is no ambiguity in India’s intent; no dual-use argument cloaked in scientific jargon. The credibility of these missions lies in their open, collaborative character.
The commissioning of INS Sandhayak — the first in its class of next-generation survey ships — in February 2024 has given this capability a significant boost. The vessel marks a technological leap in India’s maritime mapping efforts, featuring advanced sonar systems, digital processing suites, and enhanced operational endurance. It also marks a shift in mindset, with India now viewing hydrography not merely as a support function, but as a frontline tool of engagement and influence.
Another consequential aspect of India’s maritime engagement is human capital development. As of June 2024, over 800 professionals from 41 countries, the vast majority from IOR states, have received training at India’s National Institute of Hydrography in Goa. These are not mere technical apprenticeships; they are genuine capacity-building initiatives that empower countries to independently survey, map, and safeguard their maritime spaces. Notably, India offers these capabilities without hidden costs — freely sharing tools, with no licensing fees or political quid pro quos.
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No longer a backstage discipline
For all its strategic utility, hydrography remains under-recognised in India’s maritime imagination. Still seen by many as a technical support function, it lacks the gravitas of more visibly combat-oriented missions. That mindset needs to change. As maritime competition shifts toward peacetime shaping and strategic presence, rather than force projection alone, the ability to map, monitor, and interpret the marine environment will be a decisive enabler of influence.
Undersea survey may lack the sheen of combat, but it is fast becoming central to maritime credibility, enabling presence where it matters, when it matters, in quiet and persistent ways. In the years ahead, India’s leadership in the Indian Ocean will hinge less on the firepower of its warships and more on the precision of its technocratic engagement. More often than not, that journey will begin with a map.
Abhijit Singh is a retired naval officer and former head of the Maritime Policy Initiative at ORF, New Delhi. Views are personal. He tweets @abhijit227.
(Edited by Aamaan Alam Khan)