Dulaji-class research ship

The Dulaji class are a class of environmental research ships (AGER) currently in service with the People's Liberation Army Navy (PLAN), and the design is also modified for cable layer (YRC) in PLAN service, with both versions have received the same NATO reporting name Dulaji class because they share the same hull. The exact type of this class remain unknown as of 2022, because no official information has been released, despite the ships have already been in service for more than a decade. In addition to the usual task of conducting regular environmental sampling, monitoring/surveillance and research missions, these ships are also tasked with additional task of sewer transfer and treatment from other ships to prevent sewer onboard other ships from overflowing into the sea and thus causing pollution, and thus these ships also act as sewer vessels for vessel sewage discharging.