The Russo-Ukrainian War at Sea: Retrospect and Prospect

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The Russian invasion of Ukraine appears, on the surface, to be a land war. Newspapers lead with photographs of burned-out tanks, and on television and online we hear about the Belorussian border and truck convoys and listen to the expert commentary of generals. But this is a naval war as well.

Fighting has taken place both around the inland capitol of Kyiv, but also on the coast and over control of key port cities. While Russian explanation for new drive in the east focuses on the Russian-speaking population and territorial expansion, there is also a second and more strategic reason: the desire for a land bridge to Crimea, which would reduce the vulnerability of the Russian naval base at Sevastopol. When examining the maritime elements of the war, three points of analysis are worth consideration: first, the nature of conflict at sea and its existence out of sight of land and in a different domain which confounds our understanding; second, how the Russian navy pursued the basic elements of naval strategy reflects their continued relevance in this century; and third, the ways in which Ukraine has adapted to the conflict, and how it might make future adjustments, requires understanding of the naval past and creative thinking about the naval future.

Sea Blindness in Theory and in Practice

Over a decade ago, Butch Brakenel and James Kraska wrote that the “United States suffers from a kind of ‘sea blindness’ — an inability to appreciate the central role the oceans and naval power have played in securing our strategic security and economic prosperity.” Most use of “sea blindness” has tended to be metaphorical or focused on the grand economic and security connections between nations and the sea. Yet, in the Russo-Ukrainian war, the United States is experiencing sea blindness in a literal sense.



As various observers scroll through social media in search of open-source intelligence on the war, we are presented with a wealth of information that we then assess for validity and usefulness. However, very little of it is focused on the seas. Photos of burned-out T-72 tanks and trucks, video clips from targeting drones, or after-action threads that summarize changes in the fighting fill our feeds. For the most part, those of us who rely on open sources are blind to what is happening on the Ukrainian coast and in the Black Sea. The exceptions, like the final stand on Snake Island or the sinking of a Russian Alligator-class LST at the pier in Berdyansk, prove the rule. The early reports of the events surrounding the sinking of the cruiser Moskva illustrate this point also. These were based on the reposting of dueling press releases or online press reports rather than imagery, video, or on-scene information, which did not start to come until well after the fact.

A handful of media outlets and online trackers are trying to keep up with the maritime war. H.I. Sutton has been keeping the Covert Shores maritime open-source intelligence outlet going with information and writes reports for USNI News when they can confirm details. But an accurate picture of what is happening at sea is difficult. Truly actionable intelligence requires more than an occasional commercial satellite image or screenshots of maritime transponders. They involve electronic intercepts, radar, sonar, and elaborate collation and analysis efforts. All of these realities mean that while the NATO navies and Russian navy are actively producing their own maritime awareness, most of the rest of us are left in the dark about the conflict at sea.

But the fact that our Twitter feeds and Instagram scrolls are not filled with naval or maritime news does not mean that nothing is happening. It is important to remember that any war which takes place in a coastal territory (and many which take place in landlocked territory) have naval elements. The Russian invasion and Ukrainian defense of their sovereignty are no different, regardless of our sea blindness.

Retrospect: Naval Strategy in Action

As Bernard Brodie reminded us, boiled down to its simplest ideas, naval strategy can be described in a clear way. It begins with the need to establish command of the sea. It is taken further by determining what to do with the control that command of the sea offers.

Establishing command of the sea does not have to be global or even regional, but could simply be local to the area of operations. There tend to be two main ways to establish command. The first is to defeat the opponent’s navy or main battle fleet. By sinking the enemy, you keep them from being able to stop your use of the sea. But there’s a second way to establish command, and that is to keep your opponent’s navy from ever putting to sea. Whether through blockade or by conducting strikes that sink them or limit their mobility while still in port, this can be equally effective.

Using the control created when you gain command of the sea is generally done in three ways. These operations are what I have previously called the “3 B’s” of naval strategy: blockade, bombardment, or putting boots on the ground via amphibious landing. Naval strategy is the mixing and matching of these operations to achieve the political ends which are the purpose of the war. This effort to establish command of the sea, and then to use it, can offer us a good way to look at Russian naval operations in the first phase of the current war.

From the earliest days of the Russian invasion, the Russian navy has largely followed a classical strategy. When Russia annexed Crimea in 2014 and retook complete control of the then divided naval base at Sevastopol, where they leased facilities from Ukraine. It also took possession of nearly three quarters of the Ukrainian navy. When the Russian invasion began earlier this year, there was little more than a “mosquito fleet” of patrol boats to stand in their way. Russian naval forces out of Sevastopol include missile corvettes and frigates as well as some Kilo-class submarines, joined by the old Slava-class cruiser Moskva as the flagship. These were reinforced by amphibious ships from the Baltic Fleet and Northern Fleets before the invasion began. These ships largely bottled up the smaller Ukrainian patrol forces in port at the start of the war and established command of sea via blockade and strikes on Ukraine’s ports.

Russians quickly created a blockade of Ukraine by closing the Kerch Strait, which connects the smaller Sea of Azov to the Black Sea and established complete control of the Sea of Azov, and stationing ships off Odessa and other Ukrainian ports. The blockade remains unannounced, and therefore legally unofficial, but is in force with a de facto status. This status quo has remained unchallenged, though the wider maritime community has pointed out the negative effects on trapped neutral vessels and ships that have come under fire in the Black Sea. The resulting commercial blockade has ensured that Ukraine is cut off from the economic lifelines necessary to support its war, making the country entirely reliant on direct financial support from the West. Secondly, it eliminated the ability to resupply the Ukrainian military via the sea, which could have moved far more material far more quickly toward the fighting in the east than trucking it from the Polish border across the entire length of the country.

With total control of the Sea of Azov and the blockade holding, the Russian navy launched its first amphibious landings as a part of the offensive against Mariupol. Russian naval doctrine is designed to avoid contested amphibious landings, instead looking for a safe place to insert troops and equipment. This landing was no different, occurring approximately 30 miles southwest of the port city, away from defenders and closer to the safety of the Crimean Peninsula.

Amphibious assaults, landings made in the face of enemy defenses, are enormously difficult. The small craft used to connect amphibious ships to the shore, as well as amphibious ships like tank landing ships which can steam right up onto the beach, are enormously vulnerable to the kinds of light anti-tank weapons which have become ubiquitous in the Ukrainian defenses. Additionally, Russian amphibious forces are designed around surface landings and do not involve vertical envelopment doctrine with helicopters like many western naval services. With these limitations in mind, Russians began making pier-side reinforcement of their ground forces until the Ukrainians sank the Alligator-class amphibious ship Saratov while she was offloading at a pier in Berdyansk. The results of this attack may have made the Russians more cautious about these kinds of amphibious reinforcements, though the Pentagon spokesman has suggested resupply via sea continues.

Mariupol represents two elements that made it a key maritime target for the Russians. First, it is a significant port on the Sea of Azov and controlling it would continue to solidify that sea as a “Russian lake.” Second, control of Mariupol is vital to establishing a land bridge between Russian territory and the “island” of Crimea which is surrounded by Ukrainian territory. The Sevastopol naval base, which has been fought over for centuries as the key to the northern Black Sea, remains vulnerable so long as it is cut off from Russia itself. Annexing not only the Crimean Peninsula, but also the territory that connects it with the rest of Russia, is a classical naval mission since it secures the safety of Sevastopol.

In addition to the blockade and putting boots on the ground, from the earliest days of the invasion, Kaliber land-attack cruise missiles launched from Black Sea Fleet were a part of the bombardment. With over a thousand missiles launched into Ukraine by Russian forces it is safe to say that several hundred of those were naval strike missions, particularly around Odessa and coastal targets. Questions remain about Russian magazines of the missiles, and their ability to reload them. The loss of the Moskva, armed entirely with anti-ship and anti-air missiles, is far less significant in this regard than the Turkish closing of the Bosporus to warships, which keeps the Russians from reinforcing their fleet.

The establishment of command of the sea was followed rapidly by using the Sea of Azov and the Black Sea for operations affecting events ashore. The Sea of Azov was closed off and Ukrainian ports were blockaded, sealing off both military and commercial traffic. The Russian navy used the Sea of Azov to reinforce operations ashore and contributed to the brutal and ongoing assault on Mariupol. And the Black Sea Fleet fired hundreds of missiles in a wide-ranging bombardment that contributed to both tactical effects but also the indiscriminate destruction of civilian targets. Regardless of the legitimacy of the Russian aggression, the legality of the maritime operations, and clear movement toward war crimes, through the lens of naval strategy and in dramatic comparison to the failures of the Russian army, the Russian navy did its job effectively.

Prospect: Sea Denial and Contesting Command of the Sea

And yet, the relative success of the Russians at sea does not mean that their naval strategy is complete. Strategy is an activity that never ends. The realities of war, the contingency of human interactions, and the shifting context of conflict in an international space, all mean that the successful execution of a navy’s strategy can shift rudder in an instant. More often than not, that comes from a change in the enemy’s approach.

The trouble with command of the sea is that while it ideally would be complete and at the very least regionally enforceable, it is never totally achieved. Alfred Thayer Mahan and Julian Corbett were clear on this in their writing. They explained that while navies and naval strategists were right to aspire to a complete or total establishment of a general command of the sea, it would almost never happen in reality. In the particular case of a coastal nation fighting an expeditionary navy on its own shores, a country like Ukraine does not need to establish command of the sea for itself, it only needs to deny it to the enemy.

Despite his reputation for being focused exclusively on battleships and the battle fleet, a caricature of his actual naval writing, Mahan wrote extensively on the need for solid coastal defense as a joint army and navy mission as a part of any nation’s naval strategy. He broke coastal defense down into three key capabilities: shore-based gunnery, the use of mines, and small attack craft — which meant torpedo boats at the dawn of the 20th century. As Jason Lancaster has written elsewhere, our modern versions of these remain available avenues of operations for Ukrainian forces as the Russian invasion shifts phases.

Today, coastal defense gunnery comes in many forms. The most obvious modern version of what used to be heavy artillery guns built into coastal fortifications are coastal defense cruise-missile systems. Rather than fixed weapons built into the stone or concrete of a coastal fort, they are often mobile and tied into a network of targeting data from radars and manned and unmanned intelligence collection systems. On April 13, 2022, Ukrainian forces reported their first successful cruise missile attacks on the Moskva. Details are unconfirmed, but we do know that the ship sank hours later while being towed to Sevastopol. While the Ukraine has a limited number of the indigenously produced Neptune missile systems, the United Kingdom has promised coastal defense cruise missiles as part of their most recent aid package. And cruise missiles are not the only weapons available for taking enemy ships under fire. The Bayraktar drones which have been used successfully against Russian armor also exist in a maritime version used by the Ukrainian navy and represent a capability that can be used against Russian warships. Additionally, munitions like the American Switchblade drones and laser-guided mortars have a more limited range but could be useful in the near littoral.

Mine warfare remains available to the Ukrainian navy as well. It is unclear to what extent it may have been used already to close off Russian operations close to shore. Russians have claimed that Ukrainians are using mines, and some have been found drifting in the Black Sea. Yet the source of those weapons is unclear, and the Russians could be using mines themselves to enhance their blockade, keeping ships from leaving port just as easily as they keep ships from entering. Mine warfare is a double-edged sword, because mining your own waters will require you to sweep them back up to make your harbors safe for commerce again, or to make them safe for resupply via sea. Ukraine may elect to use sea mines, but will likely do so in specific ways and in particular maritime geography where they are more likely to help than hurt.

Finally, coastal defense small craft remain an open question for Ukraine. The patrol vessels in its navy have already been targeted by the Russians, sinking the Solviansk in the first week of March. However, when it comes to small craft, the conversion of civilian vessels to military purposes is far easier than with medium to larger vessels. While it would likely be too difficult to mount British-supplied Harpoon missiles on small craft, the mortar tubes used to launch Switchblade drones and laser-guided mortars would be rather easy to bolt onto the aft deck of a civilian fishing or pleasure craft repurposed as naval raiders. Additionally, a recent list of new security assistance assets from the U.S. government includes “Unmanned Coastal Defense Vessels.” What these vessels look like, or their capabilities, are not clear since the U.S. Navy does not actively deploy anything that fits that description. It appears that the sinking of the Moskva has caused Russian warships to push themselves further offshore in order to avoid missile attacks. This transitions what had been a relatively close blockade to a far blockade and potentially opens up the seas for Ukrainian small craft to begin operating.

Naval Warfare in the Black Sea

In the first phase of the Russian war on Ukraine, the Russian navy largely succeeded in the basics of establishing a coherent naval strategy. It quickly established command of the sea by keeping Ukrainian ships from sailing. Once control of the waters of the southern coast of Ukraine and the Sea of Azov was established, the Russians began using it for their military purposes by blockading the coast, launching naval bombardments of targets both on the coast and well inland, and by landing boots on the ground with amphibious reinforcements of existing operations. Attempts to resupply Russian forces via the sea have been a mixed bag, with some success and some spectacular failures like the sinking of a Russian amphibious ship pier-side at Berdyansk. But the war on shore has entered a second phase. As Ukraine begins amassing more sophisticated and capable weapons, Russian forces face limitations due to the limited Turkish closure of the Bosporus under the terms of the Montreux Convention. The war at sea can shift as well.

The adoption of the classical methods of coastal defense, through the use of coastal gunnery and strike capabilities, careful employment of mine warfare, and adopting a creative approach to small craft, might allow Ukrainian forces to challenge Russian command of the sea. While they do not need to gain command for themselves, the ability to deny Russia easy and open use of the Black Sea and Sea of Azov could provide Kyiv with major benefits. The stunning sinking of the Moskva may be the turning point: As the Russian warships pull back from the coast to better protect themselves, they open more littoral maneuver space for Ukrainian forces. The adoption of greater coastal defense measures, combined with a limited guerre de razzia strategy that might even put the facilities as Sevastopol at risk, offers a clear naval strategy that will both limit the advantages the Russians established in the early weeks of the war while at the same time giving Ukrainian naval forces the opportunity to impose costs on Russian forces.



BJ Armstrong is a contributing editor with War on the Rocks and is the principal associate of the Forum on Integrated Naval History and Seapower Studies. His fourth book, Developing the Naval Mind, coauthored with John Freymann, was published in November. Opinions expressed in his article are offered in his personal and academic capacity, and do not reflect the positions or policies of the U.S. Naval Academy, the Department of Defense, or any other agency.

Image: Government of Ukraine