Type 033 Romeo-class submarine

While the Chinese Navy had more than 110 submarines in service in the mid-1980s, the total number of submarines believed to be in serviceable condition went down from 63 in 1990 to 48 in 1995. China built a total of 84 Romeo-class submarine from 1962 to 1984, with production of this obsolete design continuing for years after R-class had been scrapped from the Soviet navy. The PLAN has retired all of its Whiskey class submarines and most its Romeo-class submarines, built using Soviet designs that were based on the German Type-XXI U- boat of 1944.

The actual number of operable Romeo-class units was difficult to assess, since none of these submarines spent more than a few days at sea each year, and because of the general shortage of trained crews. Construction of their replacements -- the "Ming-class" (which is actually a remodeled R-model) and Song-class submarines -- is proceeding at the rate of about one a year.

In 1959, China began to build the improved version of the medium-sized conventional-powered submarine and conventional powered missile submarine transferred from USSR. In order to quicken the pace of using China-made components, and to make preparations for overall copying, in the construction of these two types of submarines, special attention was paid to the import of design drawings and materials of the submarine's principal accessory equipment. Thus, the import of equipment and devices was reduced; anything that could be produced in China was not allowed to be imported. When the USSR withdrew her specialists and suspended assistance, China decided to cancel some naval research projects in order to concentrate on building these two types of submarines. The production of medium-sized conventional-powered submarine began in Jiangnan and Wuchang shipyards, the first one was completed in December 1965 in Jiangnan shipyard. Later, this type of submarine was also built in Huangpu and Fulin shipyards, and this was the largest batch production of submarine in China.

Because the materials and equipment of submarine supplied by USSR were increasingly incomplete, one after another, during the construction process components had to be replaced by home-made products. So, while the State was organizing the production of these two types of submarines, close attention was also paid to the production of materials and accessory equipment for submarine to ensure the needs of batch production of submarines in succession. In addition, during the process of building the submarines, some major technical problems, such as welding of specialty steels, propeller cavitation erosion, and ship hull structural strengthening were also solved.

The "033" class can be said to be the most representative ship of the Chinese Navy's submarine force. Many tests were performed by this class of boats. For example, the "252" boat that crossed the island chain for the first time and entered the Pacific Ocean for the first time. The 256 and 235 boats launched for the first time with self-guided torpedo tests. However, during the Cultural Revolution, the Type 033 class submarines were damaged due to lack of maintenance due to the improper management of political commanders, and their combat power was greatly reduced. Even after the Cultural Revolution returned to normal, many "033" class boats were only on the books, and could not move from the dock.

China's submarine force benefited significantly when the chaos of the Cultural Revolution was replaced by the rigid and total militarization of Chinese society in the early 1970s. This change was due partly to a growing perception of threats from the Soviet Union. Production rates of the PLAN's "Romeo"-class submarines trebled, to approximately six per year by 1974, and by 1978, China had more than 60 of these boats.

In the early seventies, China not only completed the assembly production work of these submarines, but also carried out a plan of using completely home-made parts in submarine equipment and material production. At the same time, improvement in type and technology, such as improving the guided missile launching apparatus of the improved version of conventional-powered ballistic missile submarine and increasing the air-conditioning and refrigerating capacity of the improved version of conventional-powered submarine, were carried out.

In the late 1980s, research personnel made improvements in decreasing the submarine noise, the noise level being lowered by 12 decibels from its original level, thus enhancing the submarine concealment capability and increasing the sonar's effective distance.

After the 033 submarines were built using domestic materials, China mastered the medium Type 033 conventional power submarine Type 033 conventional power submarine construction technology of conventional submarine. This created a material and technical basis for China to develop a new type of conventional submarine. In terms of performance, the 033 submarine can still be regarded as a medium-sized conventional submarine with good performance in the world in the 1970s, so its mass construction has played an important role in improving the Chinese navy's maritime control, blockade, and strike capabilities.

Between 1962 and 1984, China built 84 submarines of this type, and exported a further number of them to other countries. In the 1980s, 7 ships were exported to North Korea (of which 4 were transferred free of charge). Most of China's Type 033 submarines have been retired or sealed, and only a few are still used as training boats. According to a 2002 estimate by the US Department of Defense, China had roughly 30 obsolete Soviet-designed ROMEO Class submarines remaining in the force. According to this estimate, by 2010 China will have withdrawn the ROMEO Class submarines from service. World Warships reported four remained in service as of 24 June 2012. The 2013 edition of Combat Fleets reports "fewer than 10". Asia Military Review reports 8 Romeo-class for "training and reserve only" while World Defense Almanac 2013 reports 30 boats in this status.

In addition to the roughly 30 obsolete Soviet-designed ROMEO Class submarines remaining in the force, by 2002 China had produced two domestically designed diesel-electric attack submarine classes: the MING and the SONG Class SS. China has launched 21 MINGs and three SONGs. The MING essentially is an improved version of the ROMEO. The SONG, on the other hand, is China's first new-design, conventionally powered submarine. By 2010, China had withdrawn the ROMEO Class submarines from service.