Kamikaze drones call for a coordinated response
As the drone threat at sea evolves, India and other regional states must work alongside more capable partners.
It’s open season for Houthi militants in the Red Sea and Gulf of Aden. A spate of missile and drone attacks on merchant ships in the region has sent tremors rippling across global capitals. Worryingly, in at least four instances in recent weeks, the attacks have occurred either on ships with Indian crews or in waters close to India. In the latest incident on January 17, a Marshall Island-flagged merchant vessel, the MV Genco Picardy, reported a drone attack in the Gulf of Aden. For the second time in less than a month, the Indian Navy responded with alacrity to a call for assistance, dispatching the INS Visakhapatnam, a guided missile destroyer, to the scene of the incident. An explosive ordnance team from the warship boarded the vessel to inspect the damaged area and rendered the area safe for further transit after a thorough inspection.
The uncanny consistency with which these drone attacks have occurred in the western Indian Ocean is perplexing. It is compounded by the fact that the source of these attacks remains unknown. When the Chem Pluto incident occurred a few weeks ago, naval investigators discovered that the debris at the scene matched parts of an Iranian suicide drone, ostensibly Shahed-136. US intelligence is reported to have corroborated that finding, and Indian external affairs minister S Jaishankar raised the issue with Iranian leaders during his recent visit to Tehran, although not publicly. He may have been dissuaded by the fact that evidence of Iranian involvement, though persuasive, was far from explicit.
Shahed-136 is a kamikaze or suicide drone. A “loitering munition” that wanders over a predesignated area before hitting a target, it is a favourite of non-State actors such as the Houthis, not merely on account of its ease of usage but also because it is known to leave a thin trail of evidence. While slow-moving and vulnerable to air defence, Shahed can be silently lethal, especially when used against merchant ships with no anti-drone sensors and weapons.
Shahed-136 was used for the first time in September 2020 in Yemen, and since then has been frequently deployed by the Houthis against merchant ships, including in the attack against the tanker MT Mercer Street in July 2021 and the Chem Pluto in December 2023. Experts point out that the Shahed’s versatility stems in part from the fact that it is both programmable and self-guided. The drone uses inertial guidance and waypoint navigation in the initial phase and then switches over to onboard sensor guidance in the terminal phase, much like a missile. It is this feature that makes it difficult to counter.
Even so, a loitering drone is unlikely to be able to target a moving ship without human intervention. The fact that several of the recent attacks have been on merchant ships in transit suggests that the drones were launched not from Iranian land, as alleged by US intelligence, but from a vessel operating near the targeted vessel. Iran is claimed to have converted many merchant container ships into drone carriers.
What lends credence to the claim is the fact that the drone attacks on merchant vessels in recent weeks have been in areas that are normally unmanned. The bridge of the ship, arguably the most attractive target for a drone strike, seems to have been spared in most attacks. The militants appear keen not to inflict injury on the crew, but rather to showcase capability and resolve. More to the point, if drones are being steered to hit select spots on a moving ship, the involvement of a human operator can’t be denied.
Of course, the presence of a human in the drone control loop has no bearing on the naval mission of detection and defence against unmanned threats. Anti-drone warfare is inherently complex, and few navies have the means to combat air and sea-borne drones effectively. The only technologies for defence against aerial drone attacks are jamming and spoofing, but these are unavailable to merchant ships. Directed energy weapons such as laser systems and high-power microwave weapons are expensive and out of reach for most regional navies. What is more, many anti-drone techniques are not known to work well in particular weather conditions.
It is worth noting that the tactics of anti-drone warfare at sea are still evolving, and some methods of targeting drones are reportedly not as effective as commonly believed. In the past few weeks, the US and the UK claimed to have shot down 21 drones and missiles launched by Yemen’s Houthi rebels over the southern Red Sea. It is yet unknown what weapons were used, but a UK defence official claimed that long-range guns and sea viper missiles were used. Arguably, overcoming the Houthi challenge in the Red Sea requires operational coordination and a high order of interoperability, which the US Navy and the Royal Navy have consistently ensured when operating together.
The Indian Navy is no stranger to integrated operations. It has a fine record of operating alongside other navies in the Gulf of Aden and recently joined the US-led combined maritime forces in the western Indian Ocean. Yet, like many other regional navies, the Indian Navy isn’t part of the US-led Operation Prosperity Guardian in the Red Sea. It also lacks the anti-drone systems needed to combat airborne unmanned platforms effectively.
As the drone threat at sea evolves, India and other regional states must work alongside more capable partners. Regional maritime forces need more than surveillance and reconnaissance capability to counter armed drones. They need the kinetic means to tackle drone attacks. Above all, regional navies need operational coordination and new engagement protocols to keep up with evolving threats in the littorals.
Abhijit Singh is head of the Maritime Policy Initiative at the ORF, New Delhi. The views expressed are personal