First, it is necessary to consider the operating principle of Shkval. When an object moves in the water, it will create bubbles around it due to its motion, which is the phenomenon of cavitation in nature. The super-cavity is a more special case, when a large air bubble appears and covers the entire object, then the object will almost fly in the air due to the maximum elimination of friction. This is the principle applied on the VA-111 Shkval super-fast torpedo. The VA-111 Shkval was researched in the 1960s as a specialized weapon for attack submarines to fight nuclear submarines and enemy surface ships. On November 29, 1977, the VA-111 Shkval super-cavity torpedo was officially accepted into service in the combat component of the Soviet Navy. Shkval torpedo uses a solid fuel engine, the head is fitted with a special cavity-forming device. It is a thick elliptical piece of metal that is sharpened with an angle of inclination to the longitudinal axis, with a circular cross-section to create an angle of elevation. In fact, a foam generator is not enough, so the torpedo head adds foaming air ducts, the bubbles are generated by a gas booster. This allows to increase the volume of air bubbles and create bubbles that cover the entire torpedo body. The Shkval super-cavity torpedo has a speed of 93 km/h out of the launch tube and up to over 360 km/h when the engine is at full capacity, twice as fast as conventional torpedoes. The warhead of the VA-111 has a weight of 210 kg, enough to break a 10,000-ton destroyer in two with a single shot. However, it should be added that besides the advantages, the VA-111 also has deadly disadvantages, making its use in combat must be carefully considered. Firstly, Shkval’s range is too short, reaching a maximum of only 6,858 m, forcing the submarine to be close to the enemy to be able to strike. This is extremely dangerous because modern warships all have advanced sonar navigation systems and extremely powerful anti-submarine weapons. Second, it is the super-cavity technology that creates superior speed that makes the torpedo unable to establish two-way communication, when the radio signal is blocked from the outside, unable to penetrate the air bubbles. The torpedo relies on estimating target coordinates prior to launch, and its maneuverability is also extremely poor, as a sharp turn would break the supercavity bubble. Third, the secrecy of the Shkval torpedo is completely absent, because it creates extremely loud noises and forms a line of bubbles floating on the water that is easy to observe. Finally, the unit price of the Shkval torpedo is said to be significantly higher than the older generation types, while the advantages are not yet outstanding. For the above reasons, guided torpedoes such as TEST-71 or Type 53-65 combined with Kalibr cruise missiles will give modern submarines a higher combat capability, especially without tethering. it faces dangerous situations like when carrying the VA-111 Shkval. Currently, Russia announced that it has initially successfully tested the Shkval 2.0 variant with a longer range and controllability. If the above weapon is soon completed, it will really be able to replace the products of the old generation.

AK-130 gunboat on Russian battleships. Photo: Internet Although born in the Soviet Union, but up to now, the AK-130 gunboat system is still a fearsome weapon with any target at sea in range. Specifically, according to expert Maya Carlin on National Interest, it is the ability to complete many tasks and high stability that the Russian Navy still believes in using the AK-130 gunboat on large warships despite the weapons. This weighs up to 100 tons. Although the development time of the AK-130 has been lengthened for a variety of reasons, this weapon has proven to be a highly efficient weapon with a rate of fire of more than 60 rounds per minute. It is known that the Soviet Navy began to have plans to own large caliber automatic cannons from the years of World War II. Artillery soldiers of the Soviet Armed Forces said that the existing cannons with caliber from 100-130mm with slow firing speed limited their ability to attack aerial targets. Therefore, in the period 1952-1955, the Soviet Union developed a number of prototype automatic cannon loaded ammunition. Automatic guns were planned for development and service in the Navy as part of the shipbuilding program for the period 1956-1965, but the plan was later abandoned. Technical blueprints bearing the plant designation ZIF-92 appeared in 1969. It was a single caliber 130mm cannon. Many of the features of the ZIF-92 gun were later applied to the AK-130 gunboat. The ZIF-92 prototype featured new, but not without deficiencies. Soviet experts planned to mount ZIF-92 on the patrol boat of Project 1135 Burevestnik. However, the ZIF-92 proved too heavy for ships of this type and forced to stay on the shelf. The Soviet Navy was finally delivered with a double-barreled gunboat in 1985. The gun was named AK-130 and was installed on the Project 956 Sovremeny destroyer. The AK-130 was developed in 1976 in the Arsenal design room named MV Frunze. With the 2-barrel design was really necessary for the gunboat because 1 barrel could not guarantee a firing efficiency of 60 rounds / min. With 2 barrels, the AK-130 cannon can fire 80 rounds / minute (each barrel shoots 40 rounds). Each bullet weighs 33kg. The AK-130’s maximum range when attacking sea and ground targets is 23km.