21820 Dyugon Landing Craft, Utility
Landing craft project 21820 Dugong was developed in Nizhny Novgorod, somewhat similar to the "Chamois", but having larger dimensions and, as a result, large amphibious capabilities. Thus, with a an overall length of 45 meters and width of about 8 meters, "Dugong" can carry up to 140 tons of load. It can be two tanks, five armored personnel carriers or infantry fighting vehicles or up to 150 troops. It is noteworthy that the carrying capacity of the Dugongs allows it to take on board three T-72, T-80 and T-90, but the size of the deck does not allow taking full advantage of this opportunity. In the case of heavy armor, the 21820 boat can carry no more than two tanks. The rest of the load may be used for infantry or other goods. Otherwise, the performance Project 21820 boats is roughly the same as that of the «Chamois».
A distinctive feature of the ship is an artificial air cavity on the bottom to achieve high speed and efficiency in the movement. The first ships dynamically supported were based on static air cushions with powerful fans and a huge fuel consumption. The air cavity vessels are more economical than the hovercraft. In both types of the special contours of the bottom is a layer for holding compressed air. This method of maintaining a dynamic principle (DPP) does not require complex design solutions and high energy costs. Preceded by high-speed landing craft project 11770 Serna, Dugong, still has no analogues in the world. "Dugong" far superior "Serna". It has low visibility, large displacement allowed at times to increase capacity and Troops capacity, speed, range, seaworthiness, with with efficient weapons fire support of landing.
It can be assumed that the Mistrals will be completed with domestic Russian Navy assault boats. The most likely candidates for this are the Project 11770 Serna and 21820 Dugong. The modern concept of warfare at sea provide proactive navies against shore installations, so the appearance of "Dugong" in the Russian Navy - is to increase its combat capabilities.
In January 2013 the Main Command of the Navy prepared a report to the Minister of Defense Sergei Shoigu, with a request to close the project of new 21820 "Dugong" air-cavity landing craft. Sailors believed that the project suffered from serious design errors. A source in the Russian Navy told "Izvestia" that the position of the main command is based on the reports of the Caspian Flotilla Headquarters, where a ship is based. At that time the Caspian Sea had "Ataman Platov", and "Ivan Kartzov" was to be launched in the Pacific. Another three were at shipyards in varying degrees of readiness.
The vessels are not able to maintain high speed due cracks in the aft hull seams. According to the sailors, problems arose due to incorrect design and assembly at the shipyard. Operational load on the hul exceeds the values ??inherent in the strength characteristics. In other words, designers and shipbuilders expected a figure of resistance, and in fact went out another higher. Because of this high-speed craft "catch the wave" and is subjected to strong hydrodynamic shock, which can even break it in half.
The air cavity is a dynamic variety of air cushions, where a layer of compressed air at the bottom of the ship is due to the movement of the ship. This is different from static air cushion, wherein the layer of air blown by fans. Thanks to the bladder are greatly reduced friction coefficients, the drag, the speed increases up to 30-50 knots.
Apart from "Dugongs", with a displacement of 280 tons, the domestic fleet has eight similar boats of the series 11770 "Serna". They are much smaller - about 100 tons displacements. One of the officers of the Baltic Fleet, which served to "Serna" notes the reliability, speed and seaworthiness. There are no problems with these boat, but they are small. They carry only a tank or two infantry fighting vehicles. Both projects are designed Nizhny Novgorod Alexeev Central Design Bureau for Hydrofoil. In fact, "Dugong" - is magnified, "Serna", able to pick up three or five armored tank. The sailors are at a loss to understand why the big boat was approved with design flaws.
According to a representative of the defense-industrial complex, who participated in the projects, the problems arose in the production phase. Laid down in 2006, "Ataman Platov" was only delivered to the Navy in 2010, but four years is not the time needed for a 280-ton boat, but for a cruiser with a displacement of 25,000 tons. That's how much time was required to build the Soviet era flagship "Petr Great".
"Dugongs" should be built on the same production facilities. But because of administrative and economic turmoil, "Platov" Nizhny Novgorod plant built the "Volga". "Ivan Kartsova" laid on "Eastern Shipyards" in Vladivostok, but had to build "Volga". And three boats were the project of the Yaroslavl Shipyard. , and jumping across the country project coffin. It is best suited for the construction of "Volga", which has gained a lot of experience on the courts hovercraft. A decision to move production was made for "socio-political" reasons.
By the time the "Ivan Kartsova" was laid down in 2010, the "Eastern shipyards" wase having serious problems with orders, and this is one of the core enterprises of Vladivostok. To prevent social tension in the city, which was preparing for the APEC Summit 2012, therefore, the construction of boats was moved here. About the same motives were in the translation production in Yaroslavl, which is less well-being than Nizhny Novgorod.
Problems with the "Ataman Platov" are well-known designers. But the sailors could take into account that this is the first ship of the project, with "childhood diseases" that are treated after additional testing. Ships with ane air cavity, moving at a speed of 50 knots ( 90 km / h ), are very difficult to hit until landing. Without these vessels, then to carry out the tasks required for landing, a massive fire suppression defense will be required. So possibly the Navy would not give up on the "Dugongs", but and ensure their completion.
The ‘Denis Davydov,’ ‘Lieutenant Rimsky-Korsakov’ and ‘Michman Lermontov’ military ships are beginning a new era of landing operations in July 2015. Where previously these ships could carry only a division of marines and only one piece of machinery, now these Baltic vessels can hold up to three war machines on board. The new ships can deliver nearly a dozen armored personnel carriers and a sufficient number of marines to take on any coastal enemy positions. The ships have been subject to extensive factory and government trials. All systems and weapons are said to be combat ready.
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