Romeo-class submarine

Project 633 was a further development of the Soviet navy's post-war 611 (Zulu-) and 613 (Whiskey-class) designs, which themselves were derivatives of the German Kriegsmarine Type XXI submarine. The project was undertaken by Lazurit Central Design Bureau of Gorky. Only 20 of the Soviet Union's originally intended 56 were completed between October 1957 and the end of December 1961 because of the introduction of the nuclear submarine into the Soviet Navy. By today's standards Romeo class submarines are considered obsolete, but they still have some value as training and surveillance vessels, they are in limited use with two navies today. The Chinese Type 033 incorporated some improvements over the original Romeo, Sonar on board was also continuously upgraded: the original Soviet sonar was first replaced by domestic Chinese Type 105 sonar, which consequently was replaced by H/SQ2-262A sonar built by No. 613 Factory. Today most of the Type 033 subs have been retired or preserved, with a few remaining in service for training purposes. • Type 033: Complete domestic production in China was achieved in 1967, and subsequently the project was renamed the Type 033. However, experience from deployment of completed boats in warmer climates proved that the original Soviet refrigeration and air conditioning system designed for subarctic and arctic area was woefully inadequate for subtropical and tropical regions, so redesigns were needed to improve refrigeration and air conditioning systems, and all boats to be stationed in tropical and subtropical regions went through such a refit. In September 1969 construction of new Type 033s, with improved air conditioning and refrigeration capability, began at Huangpu Shipyard in Guangzhou, eventually, 13 units were completed. • ES5B: Development of the Type 033G, primarily intended for export. This is an upgrade package for Romeo submarine users. The primary improvement of this class is the ability to launch wire guided torpedoes and anti-ship missiles (AShM) while submerged. The program originally began in the mid-1980s, and Egypt was reported to be the only customer when China won a contract to upgrade its Romeo-class submarine fleet, including both Soviet built and Chinese built units. This is the last type of Chinese Romeo class submarine; with noise reduction of 20 dB to 140 dB in comparison to the 160 dB of the original Soviet Project 633 submarines acquired by China. ==Operators==

Current • operates four of an original eight Romeo class submarines that are upgraded variants of the Chinese design. • operates 20 Romeo class submarines. Seven were imported from China between 1973 and 1975, and the remainder locally assembled with Chinese supplied parts between 1976 and 1995. One apparently sank in an accident in 1985. Four Chinese imported units are based on the western coast. Former • had two Romeo class ex-Soviet Navy submarines: S-10 and S-11. Delivered in 1982 and in 1983, they were decommissioned in 1989 and scrapped. • operated four Romeo class submarines (S-81 Pobeda, S-41 Viktoriya, S-83 Nadezhda, S-84 Slava). Decommissioning began in the 1990s and ended in 2011: Pobeda in 1990, Viktoriya in 1992, Nadezhda in 2008, Slava in 2011. All but Slava were scrapped. • has operated an estimated 84 of the Type-33 submarine (Romeo) during the Cold War. • and the Soviet Union had 20 Romeo class vessels in service. These vessels are no longer used as combat vessels in the Russian Navy, although one or two may used as immobile training facilities. • received three Romeo class submarines built in 1961 from the Soviet Navy: S-1, S-53, S-101. All were decommissioned in the mid 1990s and sold for scrap in 1996. == Surviving boats ==

• Changcheng 237, in Qingdao Naval Museum, Qingdao • Changcheng 274, in Taizhou Naval Museum, Taizhou • Changcheng 279, in Liugong Island, Shandong • Changcheng 280, in Shanghai Oriental Land, Shanghai • Changcheng 303, in Wuhan Science and Technology Museum, Wuhan • Changcheng 349, in 349 Submarine Sightseeing Base, Jiaojiang • S-49, in Pivdenna Bay, Sevastopol In August 2021, the "floating battery recharging station PZS-50 [formerly the submarine S-49) of project 633RV [was] being towed to a dry dock in Sevastopol for its repair" and to be turned into a museum. S-49 was decommissioned on 10 July 1995. • Slava 84, in Museum of Glass, Beloslav • The Hero Kim Kun Ok, aka Tactical Nuclear Attack Submarine No. 841, a modified Romeo-Class owned by the North Korean navy, which underwent modification in 2019, before being launched and unveiled in a ceremony on 6 September 2023. ==See also==