The Government of Thailand and the Royal Thai Navy (RTN) signed a $1.04 billion U.S. deal for three S26T air-independent propulsion (AIP) submarines from China on Friday, May 05.
In a government-to-government agreement, state-owned China Shipbuilding & Offshore International Co (CSOC) was awarded a contract to manufacture the three submarines over a period of 11 years. The S26T is a custom version of the CSOC S26 designed exclusively for the RTN.
A $20.2 million down-payment to Beijing is due in 45 days.
As per the Bangkok Post, China will also sell munitions for the submarines, these will include torpedoes and anti-ship cruising missiles (ASCM). In fact, China is reportedly supplying CM-708 ASCMs to the RTN at no extra charge. Based on the Bangkok Post’s report, these would be the 290-km range CM-708UNB.
After choosing the S26T over competing alternatives, Thailand began the process of securing the S26Ts in January – the RTN secured $383.4 million in funding from the Thai Parliament. In March, Thailand’s prime minister – Prayut Chan-o-cha – claimed to Thai media that one of the submarines will be “a free gift”, but in light of recent reports, it is unclear if this has been swapped for free munitions.
The RTN submarine program has drawn domestic criticism due to the fact that the sale was approved by the Thai government cabinet with limited scrutiny and disclosure.
The S26 appears to be the AIP-equipped version of the S20 diesel-electric submarine (SSK). The S26 has a displacement of 2,660 tons and six torpedo tubes for heavyweight torpedoes and anti-ship missiles. It can travel up to 18 knots and reach up to 8,000 nautical miles (at four knots). Its maximum diving depth is 300 metres. In 2015 Pakistan ordered eight AIP submarines – designated the Hangor-class – from China, these too are likely customized S26s.