In this initial analysis written in response to unfolding events, we explore some of the potential implications of Ukrainian success in using USVs to attack the Russians in the Black Sea.
Since the war began, Ukraine has attempted to cripple Russian ships using ‘kamikaze’ USVs packed with explosives, piloted over long distances and then rammed into the target, detonating on impact. They are operated under remote control using a satellite link and have been developed to increase their range. Various attacks have been documented but until now, the results are disputed and have mostly been difficult to verify.
Notable USV strikes have included the attack on ships in Sevastopol harbour in October 2022. The frigate RFS Makarov was attacked, although put up a strong defence and appears to have escaped damage but the minehunter RFS Ivan Golubets was struck. The second major strike of the war on the Kerch Bridge linking Crimea to Russia appears to have been carried out by detonating a USV under the bridge (16 July 2023). Several other USV attacks have been reported with Russian defenders having destroyed some of the craft.
The long reach
Following the sinking of the RFS Moskva and retaking of Snake Island, the Russian Black Sea Fleet has gradually been pushed eastward. The main naval base at Sevastopol has become a target for drone and missile attacks and is no longer the secure bastion for the fleet it once was. Considerable effort has gone into protection measures including much more robust and sophisticated boom defence for the port, attempts to camouflage vessels by painting large sections of the hull and upperworks black, fitting of additional electronic countermeasures and short-range air defence missiles.
A second generation of Ukrainian USVs with a longer range has now allowed it to strike even further east. During the night of the 3 August, the Ropucha-class landing ship RFS Olenegorskiy Gornyak was hit off the port of Novorossiysk in the eastern Black Sea. Not only did Ukraine release a clear video of the attack but it could be confidently verified by photos and video of the victim listing heavily to port as it limped into harbour. The vessel dating from 1976 is unlikely to be repaired for some time, if ever. In echoes of the sinking of the RFS Moskva, the video demonstrates further incompetence by the Russian navy. The ship is showing lights and appears completely unaware of the impending danger. Due to this total lack of readiness, no weapons engaged the drone and the terminal phase of the attack was unchallenged.
The Russians have not imposed a blackout on the coastal towns of the Black Sea helpfully allowing the drone operator a nice clear view of the ship silhouetted against the lights on the coastline. The need to blackout the coast was a lesson painfully learned by the US in WWII. Reluctance to impose this restriction on communities on the east coast was a significant factor in assisting German U-boats in slaughtering merchant ships at night in what they called the (2nd) ‘happy time’ (Jan-Sept 1942).
The following night, the same method of attack was used to strike a Russian-owned commercial tanker, selected as the target from several ships fully lit up at anchor, about 20km south of the Kerch Strait Bridge. The 6,000-tonne dwt tanker MV Sig is a sanctioned vessel known to have been used to supply oil to the Russian Army in Syria. The tanker was empty at the time but reported its engine room was flooded and requested help from tugs.
New variations on old themes
This is not an entirely new paradigm in naval warfare as some may claim, but rather a modern development of a tactic that dates back centuries. In the days of sail, fire ships were filled with gunpowder or just set on fire and left to drift into enemy vessels. In the Second World War, small craft were used to attack ships in harbour. The attack on the USS Cole in 2000 while alongside in Yemen using a water-bourne IED was a sharp reminder that simple weapons can still be dangerous. What is revolutionary is the ability to rapidly develop a weapon at low cost, utilising mostly commercially available components, able to strike moving targets with precision from hundreds of miles away at no risk to the operator.
From a strategic perspective, these successful strikes are having a much wider impact than just the damage to vessels. It could provide some leverage in reinstating the grain deal which Russia has refused to renew. These agricultural exports are needed both by hungry populations of the global south and to support Ukraine’s economy. Potentially some kind of truce could be agreed in the Black Sea to allow merchant ships safe passage. Interference with Russian shipping further hampers logistic support for their ground forces and adds to the pressure on Crimea. It also embarrasses the Kremlin by demonstrating the ever-increasing vulnerability of Russia and its military well beyond the borders of Ukraine.
A few years ago most naval analysts would have argued that developments in hypersonic/ballistic missile technology posed the greatest new challenge to navies worldwide. The war in Ukraine has shown that much simpler effectors in the form of weaponised uncrewed surface vehicles appear to present the more immediate problem. (There is a similar issue with aerial drones that are beyond the scope of this article).
These weapons are relatively unsophisticated and inexpensive (approx $250k for the first generation) offering a low bar for entry and will undoubtedly have attracted the attention of other NATO and UK adversaries ranging from terrorist groups to states such as Iran. Even larger navies may conclude that mass-producing these weapons could offer a much greater and faster return on investment in many scenarios than the development of very complex and expensive missile.
Solutions for warships
For warships, the first line of defence against USVs is training and vigilance. There may be a higher state of readiness required for longer periods and in areas that may previously have been considered ‘low threat’. This in turn will demand increased crew numbers as automation is not the complete answer, at least for now.
Although small, stealthy and hard manoeuvring surface vessels are a difficult target for radar, most warships have effective EO sensors that can detect and track close-in surface targets in the dark or in poor visibility. For the RN, increasing the number of crew-served weapons such as 50cal HMG mounts would be the quickest option for additional firepower. The Phalanx CIWS does have some anti-surface capability but it is optimised for use against high-speed airborne targets. Further refinements to its radar and software may be needed to improve counter-USV effectiveness.
Trials with Martlet missiles launched from panniers fixed to a 30mm ASCG mount were not successful due to efflux management issues. However, the development of a bespoke deck-mounted Martlet launcher to provide a 24/7 anti-USV capability could make sense. It is not possible to keep an appropriately configured Wildcat helicopter permanently airborne, even though it can be very well equipped to detect and destroy multiple USVs.
It is interesting to note how apparently well-suited the RN’s Type 31 frigate will be to address this particular threat. Equipped with 40mm Mk4 guns that can deliver up to 300 rounds per minute plus the Gatekeeper (staring) and Mirador (director) EO/IR sensors. Swarming multiple craft together to try to overwhelm defences is a likely future tactic which will demand more accurate weapons able to rapidly switch between targets.
Shipping at risk?
While USVs are certainly a concern for warships, a well trained crew should have a good chance of defeating them due to their relatively slow speed. The wider issue is the threat to merchant ships, ports and harbours globally, any of which are vulnerable to USV attack unless considerable measures taken to protect them. As we have observed before, UK naval bases and the critical civilian port infrastructure has virtually no physical protections in place to prevent entry of unauthorised craft.
The naval aspects of the Ukraine war will continue to pose questions to naval planners that demand considered but prompt action to avoid repeating Russian failures.
Main image: A few weeks before being hit, RFS Olenegorskiy Gornyak sailing near the Kerch Bridge. She was employed to transport civilian vehicles to and from Crimea while traffic was suspended due to USV attack damaging the bridge. (Photo via Saturnax / Konstantin Mikhalchevsky, 17th July 2023)