Vietnam ordered Sigma corvette

Vietnam’s growing economy, and China’s aggressive stance in the South China Sea, are pushing the country to begin a long-delayed military modernization program. Most of the equipment comes from Vietnam’s traditional Russian sources, but a purchase of Next-Gen DHC-6 Twin Otter maritime patrol aircraft from Canada showed the country’s willingness to consider other suppliers. Now comes word that Vietnam’s new Russian Gepard Class corvettes may be joined by another Western entry: 4 SIGMA ships from the Dutch Schelde shipyard.

SIGMA actually stands for Ship Integrated Geometrical Modularity Approach. Block construction has become almost routine for ships, but block design at this level is unique…

The SIGMA design uses standard, 7.2m sections, separated by bulkheads with watertight doors. That block size allows the ship to meet international requirements for surviving 6m wide damage to the ship. To add capabilities, people, or space, just add blocks to the design, and a base 50m OPV design can morph all the way to a 90m corvette (Indonesia) or even a full-featured 105m – 150m frigate (Morocco). Necessary standardization within compartment interfaces, beams, doors, portals, stairs and other key construction components adds more efficiencies.

Vietnam’s SIGMA 9814 will be somewhere in between, estimated at about 98m in length and 1,950t, with a crew of 91 or so. Thales Smart-S Mk.2 is the standard SIGMA radar, a multi-beam S-band radar with 250+ km range. It’s tied into Thales’ TACTICOS combat system.

SIGMA light frigates typically sport 4 Exocet MM40 Block 3 anti-ship missiles, whose GPS helps with inshore shots, and also gives them some land attack capabilities within their 200 km/ 108 nmi range. Triple torpedo launchers for Eurotorp light torpedoes offer close-in shots.

For defense, a set of 12 vertical launch cells typically carry VL-MICA air defense missiles. An Oto Melara 76mm super-rapid gun offers a combination of naval gunnery and last-ditch missile defense, and a pair of 20mm cannon for close-in work usually rounds out the ship’s armament.

Customers like Vietnam can change that if they want. Compatibility with the Russian weapons on its other naval ships would offer advantages of its own, and Vietnam is license-building Kh-35E anti-ship missiles. Despite these incentives, however, Vietnam seems to have opted for the standard SIGMA electronics and missile array: TACTICOS, SMART-S, Exocet MM40 and VL-MICA. That set alone will make the SIGMA frigates Vietnam’s high-end naval assets. Vietnam certainly has a long history with France, who is interested in resuming some level of defense ties.
If they choose to change other standard SIGMA standard armament, the most likely substitutions involved incorporating a Russian 76.2mm AK-176M naval gun instead of Oto Melara’s 76mm Super Rapid, and 23mm close-in guns instead of 20mm. Reports from Vietnam, however, claim that Vietnam will adopt Oto Melara’s 76mm Super Rapide gun along with its other western equipment, opting for the gun’s higher performance over fleet compatibility. Fortunately for Vietnam, the Super Rapido is arguably the world’s most popular naval gun, whose customer roster of over 55 navies includes all of Vietnam’s seafaring neighbors except Cambodia.

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