Chinese ‘Monster’ Ship Keeps Pressure On Vietnam’s Oil Fields


China Coast Guard ship 5901, known as “The Monster” for its size, has returned to the waters near Vanguard Bank in the South China Sea, where Vietnam has some important oil and gas fields.

The 12,000-ton CCG 5901, currently the world’s largest coast guard vessel, switched on its AIS, or automatic information system, on Feb. 20 near the bank, a known South China Sea flashpoint between Vietnam and China.

Data provided by the Marine Traffic website, which uses AIS signals to track ships, shows it is still at the location. 

While conducting “intrusive patrols among Vietnam’s offshore oil & gas fields,” the Chinese ship is being shadowed by Vietnam’s fisheries surveillance vessel Kiem Ngu 261, said Ray Powell, director of the U.S.-based SeaLight project, who was the first to spot it.

CCG 5901, previously carrying hull number 3901, left Sanya port in Hainan island on Feb. 14., 2024. 

Before that, it patrolled Vietnam’s exclusive economic zone (EEZ) for almost a month at the end of 2023, and was replaced on 10 Jan. by another Chinese coast guard vessel – CCG 5402.

CCG 5402 has also conducted intrusive patrols into Indonesia and Malaysia’s EEZs over the past six weeks, according to Powell.

Normalizing China’s activities

“These patrols are a key component of China’s strategy to reinforce its expansive maritime claims in disputed waters,” wrote Gaute Friis, an analyst at the SeaLight project at Stanford University in California.

“By doing so, China aims to establish a continuous presence and gradually normalize its maritime activities in these areas.”

The Chinese “monster” ship is armed with heavy machine guns and also has a helicopter platform, as well as a hangar large enough to accommodate larger rotary wing aircraft.

Vanguard Bank, called Bai Tu Chinh in Vietnamese and Wan’an Tan in Chinese, is a submerged formation that lies entirely within Vietnam’s EEZ. 

Vietnam and some foreign partners carry out oil and gas exploration at the location, which plays an important role in Hanoi’s oil and gas development.

Law enforcement vessels from Vietnam and China confronted each other there in July 2019 in one of the worst maritime standoffs between them in the South China Sea in recent years.


Radio Free Asia’s mission is to provide accurate and timely news and information to Asian countries whose governments prohibit access to a free press. Content used with the permission of Radio Free Asia, 2025 M St. NW, Suite 300, Washington DC 20036.

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