Russian oil tankers and port terminals are increasingly equipping themselves with anti-drone nets and metal cages to counter Ukraine's relentless attacks on the country's energy infrastructure. Footage captured by shipping analyst Yoluk Isik shows the 28-year-old Kaluso tanker, which is already under EU and UK sanctions, departing the Black Sea and transiting the Bosphorus Strait on Tuesday; the vessel's hull is draped with anti-drone nets and stackable water tanks.

On the battlefields of the Russia-Ukraine war, elaborate anti-drone nets and metal cages have become a key ground defense measure, but such installations had never been seen at sea before. The real-time footage of the Kaluso reveals that the ship's wheelhouse is covered in protective netting, with a metal cage over the top of the cabin. Over the past two months, Ukraine has launched the most intense maritime shipping strikes in history, persistently targeting Russian vessels in the Azov and Black Seas with the aim of cutting off Russia's crude oil export routes.

The defensive measures on these tankers appear more rudimentary and hastily assembled compared to the protective gear on Ukrainian military vehicles on land, many of which are fitted with complex, spiked metal cages. The principle behind these devices is to create a gap between the warhead and the hull, forcing the munition to detonate prematurely, thereby reducing its explosive power. The water tanks attached to the exterior of the hull draw on the defensive approach of Russian tanks, intended to buffer the impact of aerial and maritime strikes.

Samir Madani, co-founder of shipping monitoring site Tankertrackers.com, said the crew of the Kaluso not only covered the bridge with netting but nearly completely sealed off the wheelhouse, adding that "the fear is palpable." The Black Sea is a critical route for Russian oil exports as well as a vital corridor for Ukrainian grain shipments. In retaliation for the frequent maritime attacks, Russia has also targeted Ukraine's grain transportation routes.

Data from commodity pricing agency Argus shows that shipping freight rates in the region have surged dramatically. Hill Bhattacharjee, head of European freight pricing at Argus, stated, "The successive attacks have caused a large number of shipowners to hold back, unwilling to take on high-risk shipping business." He also noted that marine insurance policies are either tightening coverage terms or seeing significant premium increases. Satellite imagery, along with various open-source photos and videos, shows that the port of Novorossiysk, the area around the Black Sea Fleet naval base, and the approach channels to the port have been fitted with protective nets and various defensive fortifications. In the satellite images of the base taken by Airbus, large netted protective frames are clearly visible, and floating barriers and barges have been deployed at the port entrance to block maritime access, a defensive system that has been in place since March 2024.