The Largest Security-Cleared Career Network for Defense and Intelligence Jobs - JOIN NOW

Military


Type 927 sound detection ship

The Type 927 underwater acoustic survey ship is a new type of ship equipped by the Chinese Navy in recent years. The small-waterplane-area twin hull (SWATH) is mainly responsible for the task of detecting and tracking submarines. By 2020 there were 3 first batches of the latest 927 type of the PLAN, namely the 780 Tianxuan Star, 781 Tianji Star, 782 Yaoguang Star, with a displacement of more than 5,000 tons,

The sound measurement ship mainly provides various sonar equipment and seabed detection equipment to scan and sonar the seabed. Its functions include surveying and mapping seabed topography, drawing seabed maps for submarines, and accurately positioning submarine positions. The Type 927 underwater acoustic survey ship adopts a small waterplane area twin-hull design, and its specifications may reach a displacement of 4000-5000 tons. It is also the largest catamaran in service in the Chinese Navy. The Type 927 sound measuring ship will greatly improve the Chinese Navy's ocean-going underwater acoustic data capabilities, which will greatly help expand the scope of submarine activities and the efficiency of anti-submarine operations.

According to the practical situation of the high-performance ship, the small waterplane area catamaran is the most suitable for the investigation and experiment of deep sea marine resources. Therefore, the deep-sea equipment comprehensive survey ship mostly adopts the small waterplane area twin-hull ship type, and the propulsion method is fully-contained electric propulsion, steel, four-engine double propeller.

For surveying and mapping, specialized ships are useful, but as the Chinese Navy often needs to go out, the collection of sound signals is not as difficult as before. There are many opportunities to collect it. The work on the sound measurement ship is getting more difficult as warships nowadays are more cunning. They will activate other interference noise devices, such as a circulating pump, and turn it off during wartime. In this way, the noise will not be the same as the sonar spectrum. The seabed topographic mapping another challenge. In order to stay concealed, modern submarines will not use active sonar when underwater. In this way, the submarine is blind under sea, because the peaks on the bottom of the sea do not make any noise. At this time, in order to avoid collisions, only watching With the sea chart, the mountain will not have long legs or move.

Wherever there are mountains and where the sea is shallow, the only way to survey and map is usually by the sound measuring shipt. Therefore, China strictly forbids any sound measuring ship to work in Chinese coastal waters. China can allow American aircraft carriers to drive 170 kilometers away, but would must never allow American sound measuring ships to drive 170 kilometers away. As long as the acoustic survey ship does not draw a map of the sea floor, the submarine will not dare to approach this sea area easily. No matter how advanced the American Virginia boats are, they are useless without maps of the sea floor in shallow waters.

Since the beginning of the 21st century, the territorial water disputes between China and Japan, South Korea, Vietnam, the Philippines and other countries have intensified, as well as the Taiwan issue, leading neighboring countries to build and purchase submarines in the face of Chinas military modernization, especially the vigorous development of the navy. Confrontation to target the relatively weak shortcomings of the Chinese Navys anti-submarine strength. In addition to the advanced nuclear submarines equipped by the US Seventh Fleet, the Chinese Navy is facing greater anti-submarine pressure.

The most advanced sonar system of the U.S. military, deployed on the "Impecable", collects sonar data that is transmitted from the satellite to the shore base station for analysis or to guide anti-submarine attacks. The detection device of the system is divided into two parts. One part is "SURTASS (Towed Array Sensor System)", which is composed of passive sonar, which is towed horizontally behind the ship. The towline is 1,800 meters long and can detect the position and type of submarines from 150 meters to 450 meters underwater. The other part is called "LFA (Low Frequency Active)", which is an active sonar array suspended vertically below the ship to deal with "extremely quiet" submarines that passive sonar cannot detect. After the "Impecable" incident, the Chinese Navy also began the development of a similar catamaran detection ship. At the Huangpu Wenchong Shipyard's 927 sonar detection ship appeared. The performance and parameters of the 927 sonar detection ship can be said to be unknown, but its function is still a household name, that is, the Chinese version of the innocent number, which is the Chinese version of the sound measurement ship.

This type of sonar detection vessel was built by two shipyards, one is Huangpu Wenchong Shipyard and the other is Wuchuan Shuangliu Shipyard. So far, three ships have been launched, which are in the trial and armor stage, according to the first ship. No. 780 to infer that the ship's ship number of the ship should be 781. Since the ship launched by the navy is first brushed and covered with tape, it is obvious from the occlusion shape and size of its third number. It is 1, so surely the ship number of the No. 2 ship is 781.

In the past, the only countries in the world that had large ocean-going sound measuring ships were the United States and Japan. Of course, Japan still took a ride in the United States. Now, with the launch of the 927 sonar detection ship, it was announced to the world that the Chinese navy owned this special type of ship and capability. Prior to this, the Chinese Navy had only a small tonnage offshore measuring vessel, so it could only circle at the door. Now with the emergence of the 927 sonar detection vessel, she will greatly enhance the Chinese navys anti-submarine capability.

The performance of the 927 sonar detection ship can only be understood from the appearance. First of all, she is a large catamaran, which is conducive to the deployment of the moon pool. It is to arrange an opening for hoisting the sonar array under the middle hull, and the tail has changed. The deep cymbal hoisting equipment also has the sonar towing array of the towed equipment. Other equipment has folding jibs, tactical weitong and maritime weitong. So far, no weapons have been seen on the ship.

Due to limited information, the displacement of this type of ship has always been a mystery. According to the appearance, it should be around 5,000 tons. This tonnage can be regarded as the largest catamaran of the Chinese Navy, and its future trajectory will also cover all oceans in the world. The future anti-submarine capabilities of the Chinese Navy will take a step forward.

The number of the ship was unexpectedly not added with the Chinese prefix, but the simple number 780, which is really unexpected. Of course, this point is worth noting, that is, the Chinese Navy used to be the 037-type frigate in the past 700-799, which belongs to the category of combat ships. The use of the 700-799 section of the 927 model also means that the section has now officially become the military auxiliary ship's hull number sequence. This change also shows that the size of the Chinese navy's military auxiliary ship fleet has greatly expanded, which is another manifestation of equipment modernization.

In addition, the Type 927 marine underwater acoustic detection itself is very advanced, because the active and passive towed line array sonar system requires the vessel to stabilize at a speed of about 3 to 10 knots, which requires extremely high stability and noise of the vessel itself. The 927 model is supposed to use all-electric propulsion, which greatly reduces its own noise, and the 927 ship adopts a double-body structure, which has excellent wave resistance and stability when sailing at low speeds, which Chinese soruces claim makes the 927 perform better than the United States "Impecable" T-AGOS project.

Before the Type 927, China lacked dedicated strategic sonar towing vessels. There were only a few underwater acoustic reconnaissance ships, which were basically equipped with the same tactical sonar equipment as combat ships. In the face of the US Navys continuous increase in the Far East, Chinas navy faced advanced nuclear submarines and urgently needed an advanced underwater acoustic detection platform with strategic-level towed array sonar as a node for anti-submarine operations.

After the 927 entered service in large numbers, very low frequency sonar can be used for detection in the face of quiet new nuclear submarines of the US military. The detection range will be much greater than the legacy tactical towed array sonar carried by Chinese frigates. This means that China's future surface fleet can expand the formation security zone, drive US nuclear submarines out of the attack position, effectively detect and attack enemy nuclear submarines, make up for Chinas current anti-submarine shortcomings, and guarantee maritime territory for China's navy. With these ships, China's Navy has taken an important step toward the ocean.




NEWSLETTER
Join the GlobalSecurity.org mailing list



 
Page last modified: 01-08-2021 14:07:27 ZULU