IDEX 2017: China offers S-26 conventional submarine with Stirling engine AIP

The China Shipbuilding and Offshore International Corporation (CSOC) used the IDEX show in Abu Dhabi to market its S-26 conventional submarine for the first time with what it calls a "unique" version of the Stirling cycle engine air-independent propulsion (AIP) system.

Stirling cycle AIP systems use liquid oxygen and diesel fuel to power submarine electrical generators and extend submerged endurance.

A Stirling AIP has long been thought to equip the People's Liberation Army Navy (PLAN) Type 039B Yuan-class submarine, which forms the basis for the S-26 export variant.

A submarine model on display at IDEX and a new brochure clearly showed the S-26 has a large liquid oxygen tank to support its Stirling engine AIP.

CSOC officials would not provide an estimate of the submerged endurance for the S-26 model on display, saying it could be tailored to customer requirements.

Another industry source at IDEX familiar with AIP systems said that they doubted that the Chinese Stirling AIP, as configured, would provide submerged endurance for a week.

A CSOC brochure notes that its 2,660 ton displacement 'Conventional Submarine' has a length of 79.5 m, a beam of 8.6 m, maximum speed of 18 kt, a range of 8,000 n miles at 4 kt, and a maximum dive depth of 300 m.