Chinese research ship Beidiao 991

Chinese Research Ship Beidiao 991 is a research ship built in the People’s Republic of China (PRC) and has served both in civilian use and in the People's Liberation Army Navy (PLAN).[1][2][3][4]

History
PRC
Name	Beidiao 991
Namesake	North Investigation 991
Builder	CSIC
Commissioned	April 2008
In service	2008
Homeport	Dalian
General characteristics
Type	Multipurpose research ship (AGE)
Displacement	1,441 long tons (1,464 t)
Length	64 m (210 ft 0 in)
Beam	23 m (75 ft 6 in)
Installed power	2800 kW
Propulsion	Marine Diesel
Speed	11 kt
Range	1500 nm
Endurance	7 days
Complement	32
Electronic warfare & decoys	None

The steel-hulled Beidiao 991 adopts a Small-waterplane-area twin hull design, with 2800 kW Integrated electric propulsion (IEP), the first ship with displacement great than a thousand tons to adopt IEP in China.[1][2]Research activities are conducted on the 120 square meter afterdeck, and the five onboard labs, two on port, two on starboard, and one at stern.[1][2]The ship is also equipped with galley, conference room, command center, and various equipments for different scientific research missions, such as hydrographic, oeceanographic, geologic and acustic surveys.[1][2]Initial service proved unsatisfactory: when operating in high sea states, the ship suffered from excessive vibration which generated enough noise to prevent onboard scientific research equipment from working properly.[1][2]In addition, fuel and fresh water reserve were also inadequate, resulting in requiring frequent replenishment when deployed.[1][2]Consequently, the ship went through a major upgrade to resolve these issues,[1][2]and the lessons learned resulted Type 639 oceanographic surveillance ship that is forty percent larger with displacement reaching fifteen hundred tons. Specification:[1][2]

• Displacement (t): 1441
• Length (m): 64
• Beam (m): 23
• Draft (m): 5
• Speed (kt): 11
• Endurance (day): 7
• Range (nm): 1500
• Crew: 32
• Propulsion: Integrated electric propulsion @ 2800 kW