Thai Submarine Programme at a Crossroads

Model of S26T submarine.
Model of S26T submarine.

The Royal Thai Navy (RTN) is considering the use of Chinese-made marine diesel engines for its Type S26T diesel-electric submarine programme, which is being led by the China Shipbuilding & Offshore International Company (CSOC).

RTN spokesperson Vice Admiral Pokkrong Monthatphalin said in a 9 August statement that CSOC has offered to replace the originally proposed German-made MTU 396 diesel engines – which were offered when the order was made in 2017 but subsequently blocked from export to China by Berlin in accordance with longstanding European Union (EU) sanctions – with locally built CHD620 marine diesel engines.

VAdm Pokkrong stated that the RTN had requested more information on the CHD620 engines after CSOC proposed the alternative option in June, and has given the company till mid-September to submit the requested data. “The RTN has assigned a naval technical working group to consider these details,” he said. “CSOC is required to submit additional information by 15 September for further consideration.”

“If the substitute [engine] cannot pass the test, the navy could end the contract and seek compensation or refunds,” VAdm Pokkrong added.

In May 2017, Thailand signed a $380 million contract to procure the Type S26T through an agreement with CSOC, the international trading arm of the state-owned China Shipbuilding Industry Corporation (CSIC). The S26T is a modified version of the Yuan-class (Type 041) submarine in service with the People’s Liberation Army Navy (PLAN).

A steel cutting ceremony for the submarine was held in September 2018, and the boat’s keel was laid down in 2019. Work is currently ongoing at CSOC’s Wuchang Shipbuilding subsidiary in Wuhan and the boat is expected to be delivered between 2023 and 2024.

The RTN earlier secured approval from the House of Representatives to procure two additional S26T submarines, despite earlier indications that the acquisition could be deferred due to the economic challenges wrought by the Covid-19 pandemic.

According to company specifications, the S26T submarine displaces 2,550-tonnes at full load and measures 255 feet (77.7 metres) in length and 28ft (8.6m) in beam. The boat can be operated by a standard crew complement of 38 personnel, although it also features a large accommodation space with 46 bunks as well as a separate commanding officer’s quarters, which enable all crew members to have their own berthing space for increased comfort during extended missions.

CSOC also quotes a maximum underwater speed of 17 knots (31 kilometres per hour), dive depth of up to 984ft (300m), and an operating range of over 260nm (481km) on battery power. The boat is also claimed to offer a maximum endurance of 65 days at sea and can transit distances of up to 8,000nm (14,800km) when alternating between surface and underwater cruising.

by Jr Ng