High Quality Content by WIKIPEDIA articles! Submarines have long been one of the three focuses of the People's Liberation Army Navy (the other two are aircraft and attack boats), and when the decision was made in the late 2006 to concentrate on building other principal surface combatants to strengthen the air defense and to further delay the construction of aircraft carriers due to insufficient air cover, submarines will continue to play the lead dominant role in the assault force for the PLAN.Nuclear submarines have been envisaged in the Chinese Navy since the 1950s. Despite ambition and a long history of development, the acquisition of nuclear submarines has been a difficult process. The Cultural Revolution greatly disrupted nuclear submarine development. The Sino-Soviet split prevented any Soviet assistance in nuclear propulsion, and these propulsion problems have been troublesome to this day.