Authors: Zheng Yueyang, Wang Jin, Yang Donglin, School of Meteorology and Oceanography, National University of Defense Technology
UAVs are widely used by both sides in land battles on the Russian-Ukrainian battlefield. Ukraine has used it against Russia's maritime power, with some success. On March 24, the General Staff of the Armed Forces of Ukraine issued a document saying that Ukrainian units successfully hit two amphibious landing ships of the Russian Black Sea Fleet, as well as a number of infrastructure facilities. The reason why Ukraine has repeatedly succeeded in using suicide drones to attack the Russian fleet is that, in addition to the human factor, the fleet's lack of preparedness against such suicide attacks is also an important reason. For this type of attack, the Russian fleet needs to achieve two goals: detect and destroy incoming drones and missiles in advance, or minimize damage to the hull after the interception has not been effective. So, what are the possible countermeasures for the ships, and how feasible are these measures?
Grille armor scheme
It must be admitted that the method of attacking the fleet by suicide drones did not appear before the outbreak of the Russian-Ukrainian conflict, which means that the Russian fleet lacks the experience of relevant defense. Therefore, it is a good way to learn from the confrontation of land combat UAVs. The first option was to install an external grille armor to wrap the hull.
The use of drones in the land battlefield is much more frequent and earlier than at sea. Therefore, there is relatively more experience in the protection of UAVs on land. Most suicide drones use armor-piercing warheads, and the attack position is generally the weakest part of the vehicle's armor - the top cover. Both Russian and Ukrainian armored forces have learned from the first destroyed tanks, equipping tanks and armored vehicles, etc., with external grille armor and placing additional protective nets on top of the tanks. These protective nets can trigger the opponent's armor-piercing munitions in advance, reducing or avoiding damage to the vehicle hull by metal jets. At the same time, Israeli armored forces realized this even more deeply, and the first armored units to enter the street fighting in Gaza were quickly "reimbursed" by Hamas rocket artillery and drones, attacking precisely the weak sides and roof of the tanks.
In this scheme, taking into account both the attack mode of the Ukrainian army and the combat performance of the hull itself, the grille armor is installed in such a way that an iron mesh parallel to the side of the hull is installed at a height below the hull deck, and the lower part of the net should enter the water surface about 1 meter. This is due to the fact that drones and missiles are used to attack the hull after flying close to the sea surface in order to avoid the radar detection of the ship. At the same time, the part above the hull deck needs to be able to carry out normal work on search and attack enemy targets. Therefore, it is only necessary to install this grille armor in the lower circle in this way. This scheme is somewhat similar to the anti-torpedo nets installed around the hulls of ships in World War I and II.
However, the drawbacks of this approach are also obvious. Take, for example, the American mobile artillery system M1128 "Stryker". The M1128 itself weighs 18.7 tons, and if it is equipped with grille armor that circles the body, the total weight will come to 23.4 tons, which is equivalent to a quarter of the weight, which seriously affects the speed and agility of the body. For ships, the impact will only be greater, in addition to the significant increase in the displacement of the ship, the friction between the grille armor and the sea water will also seriously affect the maneuver of the hull, such as the ship's extreme speed drop, fuel consumption will become higher, and the turning radius will increase. The fact that a fence around the outside of a ship does not require a high level of technology, but that no country has been seen to implement it suggests that this measure will do more harm than good, at least for now.
Fig.1 Schematic diagram of the ship equipped with double-layer grille armor
Active defense system scheme
Another option is an active defense system (APS) that can "defuse" enemy attacks in advance. This system is currently equipped on a number of tanks and can be used to protect against chemical weapons. The principle of APS is that after the scanning device detects a rapidly approaching object, it fires interceptor ammunition (usually explosives equipped with a proximity fuse) outward in the corresponding direction to detonate the opponent's ammunition in advance, so as to avoid damage to its own vehicle hull, such as Israel's "trophies" and Soviet "thrushes". Active defense systems have a good defense against relatively slow weapons such as rockets, anti-tank missiles, etc. During the Palestinian-Israeli conflict, the "Merkava" tank can often be seen on the turret.
However, the shortcomings of this product are also very obvious, APS can not defend against armor-piercing bullets and other high-speed kinetic weapons, and the operation of the scanning device is a huge power consumption, easy to be accidentally touched by objects that do not need defense, the most lethal is that the infantry often refuses to cooperate with the tank equipped with the APS system, because the interceptor ammunition it launches outwards has a huge lethality that does not distinguish between the enemy and us. In addition, APS is not a "one-size-fits-all" barrier. Among the tanks destroyed by the 105 rocket launchers of the Israeli army, it is not uncommon for the "trophies" to fail to detect the incoming rockets and fail to intercept them. And at the moment, it is also unrealistic for ships to equip with similar systems to defend against drones and missiles. The most complete radar system on the missile cruiser "Moskva", which was sunk by the Ukrainian "Neptune" missile, did not detect the missile attack and intercepted it, so this narrowed version of the close defense system is even more insignificant.
Fig.2 A Merkava equipped with "trophies" was badly damaged during the escape
Water curtain barrier scheme
Battles on land can involve digging trenches and fortifications, while the sea around ships is infinite, and you can use seawater as a barrier to protect your ships. This scheme, called "Volna", may be a good reference.
Figure 3 Conceptual diagram of the water cannon barrier
The Volna scheme consisted of powerful pumping pumps and water cannons mounted on the hull. When a local missile or drone approaches the hull, the water cannon in this direction will shoot a column of water with great pressure downwards to form a water curtain, wrapping the hull in this direction to form a barrier, so as to reduce the damage to the hull caused by enemy attacks.
Another significant advantage of this solution is that it affects the targeting of the opponent's attack. The jet of water creates a large amount of water mist that envelops the hull, which seriously affects the precision strikes of enemy hand-guided suicide drones on the location of the attack target. At the same time, these water mist can mask the heat generated by the operation of the hull due to the low temperature relative to the hull, and also have a certain interference effect on anti-ship missiles using infrared guidance. However, as far as the current situation of the Black Sea Fleet is concerned, this plan cannot be realized in a short period of time, both economically and technically.
Up to now, the Russian-Ukrainian war has been going on for more than a year, and the once glorious Black Sea Fleet is in an awkward situation and has been repeatedly attacked. First of all, Ukraine does not have a navy in the true sense of the word, which leaves the fleet with no opponents to attack. And Ukraine's frequent attacks and encroachment, coupled with the crushing of NATO information and intelligence, made the already difficult fleet even worse, and had to hide in the port. The core of the Black Sea Fleet itself is at the Black Sea Shipyard in Nikolaev, and after the independence of Ukraine, the Black Sea Fleet has basically lost its "blood-making" ability and can only rely on the remaining ships as a body to continue to support. As netizens said, at the beginning of the establishment of this fleet, they did not expect that Ukraine would become their enemy. The current fleet can't get out of the country, it wants to support the battlefield but can't get close to the land, and it wants to be a deterrent but is disgraced by attacks every day. It's a pity to discard it. The Black Sea Fleet has not come up with an effective response to Ukraine's constant attacks until now. Let us not help but sigh, how far can the current Black Sea Fleet go?