The Soviets started assisting China in the production of ROMEO submarine in 1959. The Chinese variant is known as the Type 033 . The Chinese Type 033 incorporated some improvements over the original ROMEO, including noise reduction of at least 20 dB. A total of 84 Type 033 submarines were built in China from 1962 to 1984, plus several exported to other countries. Today most of the Type 033 submarines have been retired or preserved, with few remaining for training purposes.
