Undersea Warriors

China is building the first-ever single-hulled submarines

Prasun K. Sengupta

China Shipbuilding Industry Corp (CSIC), the export arm of the state-owned China Shipbuilding and Offshore International Company (CSOC) unveiled three all-new designs of submarines at the Defence & Security 2017 exhibition, which took place from November 6 to 9 in Bangkok. The three designs — MS-200, S-600 and S-1100 — are all single-hulled (a first in China’s submarine-building history) and can also accommodate Stirling Engine-based air-independent propulsion (AIP) systems developed by CSIC’s 711th Institute.

CSIC's S-1100 (above) & S-600 SSKs
CSIC’s S-1100 (above) & S-600 SSKs

The 200-tonne MS-200 features adopts a teardrop and single-hull structure, while its sail has a three-dimensional streamline shape, and its steering plane comprises bow hydroplane and cross-stern rudder. The vessel has a length of 30 metre; breadth of 3.6 metre and a height of 4.4 metre. Maximum cruise speed is about eight Knots, submerged range is 120 nautical miles (nm), and a mixed range about 1,500 nm. Maximum diving depth is 200 metre, endurance is 15 days at sea, while the service life is 25 years.

The MS-200 has a crew complement of six sailors, plus eight Special Forces personnel. It also comes armed with twin torpedo tubes. The 600-tonne S-600 has a length of 50 metres, breadth of 4.6 metres and a height of 5.6 metre. Maximum submerged speed is about 15 Knots (9 Knots when surfaced), range is 2,000 nm (400nm while submerged and using AIP). Maximum diving depth is 200 metre and endurance is 20 days at sea, while the crew complement is 15. The S-600 comes armed with four torpedo tubes.

The 1,100-tonne S-1100 submarine has a length of 60 metres, breadth of 5.6 metres and a height of 6.8 metres. Maximum submerged speed is about 15 Knots, range is 3,000nm (800nm while submerged and powered by AIP), maximum diving depth is 200 metres, and its endurance is 30 days at sea. The vessel is manned by crew of 18, while its service life is 25 years. The S-1100 also has four torpedo tubes.

According to CSIC, the double-hulled S-26 submarine, also powered by Stirling Engine AIP, is the export designation for the Type 041 Yuan-class diesel-electric submarine. To date, four S-26s have been ordered by Pakistan (along with four S-32 Qing-class double-hulled boats) and three by Thailand. The S-26 is 77.7 metres long, has a beam width of 8.6 metres, and a height of 9.2 metres. It can dive 300 metres deep, its maximum submerged speed is 17 Knots and its range when using AIP is 768nm, or 20 days. The maximum range for mixed AIP and diesel-electric travel is 2,000nm, or 65 days. The teardrop-shaped hull accommodates a crew complement of 38, plus eight Special Forces personnel.

For manoeuvring purposes, the S-26 employs a cross-stern rudder and bow hydroplanes. An optronic mast is fitted on the sail, while the six 533mm torpedo tubes can launch both Yu-5 active/passive homing heavyweight torpedoes as well as C-702A subsonic anti-ship cruise missiles. The entire hull is built from continuously-casted 921A and 980 steel (with yield strengths of 590-745MPa and 785MPa), while the hull-sections are assembled using the Hull Block Construction Method. The on-board diesel-engine used is the 396 SE84 series that is imported from Germany’s MTU Friedrichshafen GmbH. The outer hulls of the S-26 and S-32 submarines are clad with anechoic tiles for minimising any return echoes when pinged by active sonars.

Altogether, the S-26 has six compartments. The first is the weapons and fore battery compartment, followed by the command compartment, living quarters and aft battery compartment, diesel-engine and generator compartment, AIP compartment, and the shaft machinery and driving motor compartment. All S-26 and S-32 submarines are being built by CSIC’s Wuhan-based Wuchang Shipbuilding, with deliveries beginning in 2020.