Explained: What Is The Underwater Bomb That Ukraine Used To Blow Up Crimea Bridge; Can India Build One Too?

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New Delhi: A quiet splash. A dark current. And then, chaos. Concrete cracking. Steel shattering. Russia’s mighty Crimean Bridge, once a symbol of unbreakable control, was torn. Not by fighter jets. Not by missiles. But by bombs, sleeping silently beneath the waves.

On June 3 morning, Ukraine’s security service SBU claimed responsibility for a jaw-dropping underwater strike on the Kerch Bridge, an important supply line between Russia and the occupied Crimean Peninsula. The attack, which reportedly used 1,100 kg of explosives, targeted the bridge’s underwater pillars – crippling its foundation without firing a single bullet above the surface.

The SBU said the mission took months of planning, involving the stealthy planting of explosives beneath the bridge. At exactly 4:44 a.m., the bombs were triggered. No warnings. Just impact. Russian authorities scrambled to shut down traffic twice that day. By evening, a temporary fix was in place but the damage had been done, both physically and psychologically.

“God loves the Trinity. The SBU always sees things through. We never do the same thing twice,” said SBU chief Vasyl Malyuk, referencing this being their third successful strike on the bridge.

A chilling message and a direct blow to Vladimir Putin, who had personally inaugurated the $3.7 billion structure after annexing Crimea.

What Exactly Is an Underwater Bomb?

Think of it as a torpedo without the motion. These devices, designed for stealth and shock, are planted on or near underwater structures. Often placed by divers, underwater drones, or submersibles, they are programmed to detonate on command or via timed triggers. And unlike airstrikes, they are nearly invisible until they explode.

These are not ordinary explosives. They are built to withstand water pressure, avoid detection by sonar and deliver focused kinetic blasts that cripple foundations from beneath. That is exactly what happened at Kerch.

Does India Have Plans for This?

While India has not publicly revealed plans for underwater bomb programs like Ukraine’s, quiet steps are being taken. According to naval insiders, the Defence Research Development Organisation (DRDO) and the Indian Navy are actively evaluating unmanned underwater systems (UUVs) that could be retrofitted for attack roles, not just surveillance. There is growing chatter around seabed warfare capabilities, especially in the context of defending critical assets like undersea data cables and offshore oil platforms.

The idea is not far-fetched. India’s elite MARCOS commandos are trained in combat diving and sabotage and can plant demolition charges underwater.

What is missing is formal doctrine and deployment at scale. But after watching Ukraine use a silent underwater detonation to rock a $3.7 billion bridge, defence circles in Delhi are asking tougher questions and demanding faster answers.

What’s India’s Naval Response to China’s Threat?

India knows the seas are where the next silent war could unfold. With China’s presence growing in the Indian Ocean, from Gwadar in Pakistan to Hambantota in Sri Lanka, India is no longer taking chances.

There has been a visible ramp-up of maritime surveillance drones and naval exercises with Quad partners and expansion of island radar stations across the Indian Ocean rim.

But it is not just about eyeballing Chinese warships. India is betting big on indigenous tech, and that includes underwater autonomous platforms. INS Arihant and INS Arighat, nuclear submarines built under India’s Advanced Technology Vessel project, are part of a broader long-term response.

But naval minds are also pushing for lighter and stealthier systems like drone swarms below water that can strike before they are seen.

How Do Underwater Drones Operate in Combat?

They move like sea creatures. Slow. Silent. Invisible. Underwater drones or Autonomous Underwater Vehicles (AUVs) operate with pre-programmed coordinates. In combat, they are used for mine detection, surveillance and increasingly for attack missions.

They can glide through the sea like torpedoes, latch onto targets like limpet mines and detonate without warning.

Ukraine has turned them into weapons of disruption. India is figuring out how to turn them into weapons of deterrence. But the blueprint exists, and the timing, in a region where tensions are always bubbling under the surface, could not be more urgent.