What the Sinking of the Russian Corvette Ivanovets Teaches

Ukraine’s sinking of the Russian missile corvette Ivanovets on 31 January with unmanned surface vehicles (USVs) has caused naval analysts to again note the impact drones can have on the modern battlefield. Analysis of the sinking has shed new light on surface warfare involving unmanned surface vehicles and suggests that old and seemingly obsolete tactics involving maneuverability and firepower may be new again.

Early analysis of the sinking has noted apparent deficiencies in watchstanding or material condition that rendered the Tarantul-class corvette incapable of defending herself.¹ However, this conclusion neglects the extreme environmental constraints the Ivanovets faced. The ship reportedly fought the Ukrainian Magura V5 USVs on Crimea’s Lake Donuzlav, a funnel-shaped saltwater inlet whose widest point measures about six nautical miles and that, except for a narrow channel, is enclosed on all sides by land. The USVs physically impacted the ship before exploding. In such a constrained environment, faulting the lookouts or equipment would be akin to blaming a person for losing a game of tag inside a small, locked room. Deficiencies in lookouts or radar may have played a role in the incident, but it is not known why Ukraine’s USVs were able to successfully approach the Ivanovets.

Firepower and Maneuver

Nevertheless, to the extent the Ivanovets was able to last against the Ukrainian drone swarm, analyzing the balance between maneuver and firepower suggests some conclusions. From video provided by Ukraine’s Main Director of Intelligence, the Magura V5 USVs appear to evade crew-served weapons fire from the Ivanovets by “chasing splashes,” a method of fire evasion used by small, fast surface ships such as destroyers since the introduction of analogue fire-control systems.² The tactic involves steering one’s vessel toward the splashes made by a miss from the enemy’s last salvo. As the enemy gun director corrects aim from the splash to the actual location of the target, the target vessel maneuvers toward the location of the splash, thereby causing the enemy’s aim correction to again result in a miss. U.S. Navy Commander and Medal of Honor recipient Ernest Evans used this tactic during the October 1944 Battle off Samar to close on Japan’s battleship Yamato so his destroyer, the USS Johnston (DD-557), could reach torpedo-firing range.

With its jet-ski propulsion, the Magura V5 has an approximately six-knot maximum speed advantage over a Tarantul-class corvette.³ The Ivanovets can be seen on video maneuvering at high speed away from the USVs seeking to collide with her, but a six-knot disadvantage in constrained waters can prove fatal against an enemy seeking collision if sufficient defensive firepower cannot be brought to bear.

Speed has a long and often tragic history for ship defense. In the early 20th century, British First Sea Lord Sir John Fisher advocated against constructing battlecruisers with armor protection that sacrificed speed. “Their speed is their protection,” he said, believing that their maneuverability could keep them outside the effective range of Germany’s battleships.⁴ Instead, at the 1916 Battle of Jutland, British battlecruisers were sunk in part because the British and German ships unexpectedly encountered each other in the North Sea fog and the battlecruiser commanders engaged within effective range of the German guns.

Because the Ukrainian drones were able to close the distance, the Ivanovets was forced to engage at close range with what appear to be crew-served machine guns. When defending at close range against a swarm of targets, such point-defense weapons leave the ship vulnerable because of a lack of sufficient firepower. A machine gun cannot engage multiple targets on the water simultaneously, a critical weakness if it is the sole defense against swarms. As can be seen from the video, a single crew-served weapon without sophisticated gun control may struggle to score a hit on a fast-moving USV. If one disregards technical specifications or operator skill, the accuracy of crew-served weapon fire becomes a product of volume of fire and range. As volume increases, or range decreases, the chances of scoring a hit increase.

Maneuver and point defense inevitably conflict. Because point defense tends to use stationary weapon systems, it remains vulnerable to masking. This problem may be exacerbated if a ship receives battle damage that renders one side’s weapons unable to fire; attacking vessels may simply be vectored into the damaged side and away from the side with still-functional defenses. Attempting to unmask the weapons of the undamaged side would require a ship to turn toward an approaching USV that would have a significant advantage in maneuverability.

The conflict between maneuver and point defense vanishes if a ship remains outside a USV’s effective range or engages at safe range. Effective range requires speed, space, and reaction time to lengthen the kill chain. Safe range requires a reliance on weapons beyond those of point defense, especially those using digital computerized fire control or smart ammunition such as that with proximity fuzes.

For the U.S. Navy, lightly armed littoral combat ships can achieve speeds greater than 40 knots. On the other hand, the Aegis weapon system of Arleigh Burke–class destroyers permits engagement of multiple targets simultaneously and at range, but the ships lack swift evasive speed and maneuver. Against high-speed USVs, LCSs and destroyers each lack the other’s strength. If USVs are here to stay, the Navy must relearn how to balance speed and firepower to give its sailors the best chance to defend their ships. Vessel speed has once again become tactically significant.