This article on USV attacks is written by Mr. Hasan Özyurt, (R) Rear Admiral, currently working at Meteksan Defense Inc. as Management Consultant
In the first phase of surface warfare, the search and detection of opposing surface force units are crucial. When targets are in port, this phase is relatively easier. However, in the last two attacks, the target ships were underway, making the search more challenging. Measures taken at bases and ports may have led to the selection of underway ships as targets. When the target is in open waters and underway, intelligence, reconnaissance, and surveillance activities become essential. Given Ukraine’s limited reconnaissance capabilities, it is likely that the intelligence on the targets came from another source. Another possibility is that kamikaze USVs are used in an “area operation” style, performing both reconnaissance and attacking when a target is identified.
Suppose Ukraine has intelligence indicating the potential location of targets in a specific region. In this case, the planning should consider factors such as USV range, transit speed, weather and sea conditions in the target area, and the preference for conducting the transit and the attack under night conditions. With the attack locations being 125 to 150 nautical miles away from Odessa, kamikaze USVs must have started their transit at least 4-6 hours before the attack. If intelligence includes information on the target elements’ pattern of life, such as routine transits and planned patrol missions, the planning becomes more feasible.
USVs might have pre-transited to the operational area and waited for their targets. Such a mode of operation, defined as an “area operation,” could be effective, especially in an environment where the adversary’s airborne surveillance capabilities are limited.
Once the target is identified and classified as an “enemy,” the engagement phase of surface warfare begins. Tactical maneuvers, including previously exercised template maneuvers adapted to the situation and target type, are applied during the attack. Kamikaze USVs pose an asymmetric threat to target ships due to their size, boat forms, and advantages in radar and optical systems even in normal sea, air, and visibility conditions. Ukraine’s successful utilization of this asymmetry is evident from the results.
The situation in the attack on the Ivanovets corvette is different from the non-combatant Caesar Kunikov, which might not have exhibited observable defense efforts. Ivanovets, being a combatant with both defensive weapon systems and high speed and maneuverability, attempted various defensive actions. Observations indicate that Ivanovets tried to increase speed, performed evasive maneuvers, and engaged the kamikaze USVs with the AK-630 rapid-fire batteries. Despite these efforts, Ivanovets could not prevent the USVs from reaching her, leading to a loss of firepower and, ultimately, sinking. As a naval officer, it is disheartening to see Ivanovets making every effort to defend herself but failing to avert a tragic end. The ship’s company seemed to fight until the last moment, but they couldn’t overcome the technological asymmetry.
Videos released by the Ukrainian side, although likely edited for propaganda and/or intelligence reasons, allow some analysis of the attacks. It is apparent that Ukraine used 6-10 boat packs in the kamikaze USV attacks. Some USVs, possibly a reserve attack pack, stayed in the background at a distance of 2000-3000 yards, waiting for the results of the initial attack pack. The USVs applied a similar attack pattern in both the Ivanovets and Caesar Kunikov incidents. They did not execute maneuvers like Simultaneous Time On Target (STOT), suggesting low autonomy support, remote-controlled maneuvers, and the application of a “swarm” tactic with approaches from different sectors and sequential attacks. The primary objective of the attack is to achieve the first impact on the target ship. After this impact, the ship would slow down, and its defense capabilities would diminish, allowing subsequent attacks to render it completely ineffective. The warhead carried by the USVs (likely over 200 kg) is lethal enough for this purpose. In the final approach (terminal maneuver), the USVs accelerate to high speed and perform zig-zag maneuvers of +/- 30-45 degrees, aiming to minimize the probability of being seen, locked onto, and hit by defensive fire.
Ivanovets engaged the kamikaze USVs with its AK-630 Close-In Weapon System (CIWS), featuring a high firing rate (30 mm, 4000 rounds/minute). The infrared camera images show glowing weapon barrels and firing at the USVs are visible. The AK-630 system, designed primarily for defense against guided missiles, can be used with both a fire control radar director and an operator-controlled optical director. The system has an effective range of 5000 meters against surface targets. Ivanovets detected the kamikaze USVs, but this detection probably occurred at a relatively short distance, likely through a radar or hearing the sound of the USV engines. The proximity of the detection, combined with the high speed of the USVs, did not allow sufficient time for defensive reactions. Additionally, the defense shots were likely made by the AK-630 optical director operator. This implies that there was no automatic radar or electro-optical lock, and the operator aimed manually. Even in the case of individual USV attacks on the ship, this defense, which proved unsuccessful, would not be effective against USVs approaching simultaneously.
One notable aspect of the recent USV attacks is their ability to target specific areas of the ship. This capability, absent in other weapons (except for some of the most advanced anti-ship missiles), allows critical areas of the ship (rudder, engine room, hatches, previously opened wounds) to be affected. After such an impact, even if the ship does not sink, it may be incapacitated and non-operational for an extended period.
We see that kamikaze USVs are capable of sinking a ship. When used in conjunction with current intelligence and other capabilities, these weapons can influence the course of naval operations. After Ukraine’s repeated demonstration of this concept, we can predict that similar weapons, or even more advanced versions, will quickly become widespread, acquired, and used by both state and non-state actors.
The question of what can be done (or could have been done) to defend against kamikaze USVs should be asked in terms of both existing capabilities and what capabilities need to be developed. While the options with existing capabilities are limited, they can be effective when correctly applied. Measures such as physically blocking base and port entrances with barriers that prevent USV access, monitoring base and port approaches with suitable search radars and optical systems, establishing continuous patrols with fast boats armed with high-firing rate weapons, and supporting these patrols with armed helicopters would be a good start. We can assume that Russia has taken similar measures. Moving bases beyond the USV access range could be another preventive measure, but USVs may quickly acquire the range capability or be deployed from motherships to overcome these distances.
Measures that naval elements can take will primarily rely on maintaining a high state of readiness and providing early warning. Maintaining high readiness states of machinery (for full-speed evasive maneuvers), material (greatest degree of subdivision and watertight integrity) and weapons (to be able to counterattack) is crucial. Providing early warning, however, is not straightforward with existing sensor systems. The dimensions of USVs and their IR signatures prevent their detection at distances sufficient for early warning. Passive sonar listening may, in some cases, allow detection of the underwater noise generated by USV propulsion systems, but USVs may respond by approaching at low speed up to a certain distance. Even with current sensor technology on ships, detecting USVs at sufficient distances is challenging. Radar, electro-optical, and optical surveillance must be maintained continuously. To enhance early warning against USVs, aerial reconnaissance proves to be one of the most effective measures. This way, USV activities can be detected in advance, enabling the implementation of necessary precautions. In situations where environmental conditions diminish the effectiveness of aerial reconnaissance, it is presumed that procedural measures can be applied, considering the increased threat of USVs.
The most critical aspect of defense is training. Coordinated and effective defense reactions and the ability to sustain the ship’s combat capability depend on well trained and prepared personnel. Realistic training using similar boats (preferably USVs) to conduct realistic exercises would be appropriate.
On the other hand, in areas where the kamikaze USV threat is high, escorting the ships with limited defense capabilities to reduce the risk has become a requirement. Reevaluating tactics for surface warfare against this new threat is also a necessary consideration. The answer to the question of what capabilities need to be developed to counter kamikaze USVs and other USVs lies in solutions that eliminate technological asymmetry. These solutions will include sensors that provide early warning against small targets like USVs, and a weapon system that can affect or prevent a fast and maneuverable target from reaching the ship. In a future article, we will examine the defense concept against USVs in more detail.
