Thai Navy conditionally approves ship engine to power China-built submarine

Updated at 4:24 p.m. ET on 2023-04-26

Bangkok is prepared to accept a modified ship engine to power a submarine China is building for the Royal Thai Navy provided Beijing guarantees the engine is safe, the Thai Navy commander said this week.

Thailand’s purchase of the 13.5 billion baht (U.S. $369 million) Yuan-class submarine ran into trouble because the Chinese state-owned submarine developer was unable to buy a German-built diesel submarine engine, due to a European Union arms embargo on Beijing.

The Chinese Navy would have until June to guarantee the modified ship engine’s safety, said Thai Navy Commander Adm. Choengchai Chomchoengpaet following talks in Beijing in mid-April. 

“We have three conditions to consider – the engine must be safe. Second, the Chinese navy must guarantee this engine for the Thai navy. And third, there must be compensation for the delay due to the engine change,” Choengchai said at an event in Chon Buri province on Tuesday.

“These are the important conditions in a decision on whether the contract would go on or be canceled,” he said.

If the Chinese navy agrees to the conditions, the submarine could be delivered in 40 months, Choengchai said. If the sale is completed, the submarine will be Thailand’s first since the World War II era.

The modified engine, called the CHD620, is based on German technology and is widely used, Choengchai said.

“They have been installed in many of China’s surface ships, including on aircraft carriers. They will tweak the CHD620 engine to fit into the Thai navy sub, Pakistani navy and the Chinese navy in the future,” he said. “Germany would not let them use its engine.”

The E.U. imposed its arms embargo on China in 1989 after the violent suppression of pro-democracy protests in Beijing’s Tiananmen Square.

“If we accept the CHD602 engine, the CSOC must offer a guaranteed time which is longer than usual. … Second, the company must support us in terms of engine maintenance, parts and technicians. We have to agree on this in the future,” Choengchai said, referring to the state-owned developer China Shipbuilding & Offshore International Co. Ltd.

Planned purchase of 3 subs

Choengchai said he raised the conditions for the purchase of the S26-T submarine, planned since 2017, to Li Shangfu, Chinese state councilor and minister of National Defense, and the People’s Liberation Army (PLA) Navy chief during his visit to Beijing on April 14.

“They both well acknowledged the trouble and promised that China’s navy will support the guarantee of the CHD620 engine, which is built by CSOC,” Choengchai said.

The State Council of the People’s Republic of China did not comment specifically on Choengchai’s visit.

In a statement on the day of his visit, the council posted a statement on its website “noting the solid foundation and huge potential of the cooperation between the navies of the two countries.”

The statement added that Chinese Defense Minister “Li said the Chinese side is willing to enhance the cooperation level with the Thai side, making greater contributions to safeguarding global and regional peace and stability.”

In April 2017, the Thai government approved the Royal Navy’s plan to purchase three Yuan-class submarines from China, but only one is being built because Thai lawmakers postponed the others over budgetary constraints.

The Yuan-class is a diesel-electric submarine designed to operate in shallow coastal waters, according to the U.S. Naval Institute.

After being appointed Thai Navy commander, Choengchai said in October that his force “must have three submarines in order to be equal to [other navies]” and to deal with security threats.

This story has been updated to correct the figure given for the value of the submarine Thailand is purchasing from the China state-owned shipbuilder.