Sigma-class

The SIGMA (Ship Integrated Geometrical Modularity Approach) class is a family of modular naval vessels designed by the Dutch Damen Group. The design is derived from the High Speed Displacement hull form developed by Marin Teknikk AS in the 1970s. The series is characterized by its modular construction method, which utilizes standardized hull segments to produce vessels of varying sizes, categorized as either corvettes or frigates.

The design architecture allows for variations in length and beam by changing the number and sequence of hull segments. These dimensions determine the individual variant designations, such as the 9113 or 10514. The vessels utilize diesel propulsion systems driving controllable pitch propellers and incorporate passive roll stabilization. Integrated systems typically include the Thales Tacticos combat management system, multibeam surveillance radars, and hull-mounted active/passive sonar. Armament configurations are determined by the operator but generally include a main gun, anti-surface missiles, anti-air missiles, and torpedo launchers. Aviation facilities include a landing deck, with larger variants featuring a permanent hangar.

Operational service began with the Indonesian Navy, which commissioned four 9113 corvettes—the Diponegoro class—between 2007 and 2009. Indonesia later expanded its fleet with two 10514 frigates, the Martadinata class, commissioned in 2017 and 2018. These frigates were built through a modular collaboration between Damen and PT PAL Indonesia.

The Royal Moroccan Navy operates three vessels: two 9813 heavy corvettes and one 10513 light frigate, all delivered between 2011 and 2012. The Mexican Navy operates one 10514 variant, ARM Benito Juárez, which entered service in 2020 as a long-range ocean patrol vessel. This ship was assembled in Mexico using two modules built in the Netherlands and four modules built locally.

In 2024, the Colombian Navy signed a contract with COTECMAR for the construction of a frigate based on the 10514 model, with construction scheduled to begin in 2026. While several other navies have considered the SIGMA design for procurement programs, including Greece and Poland, other bids in Brazil, Egypt, and Oman were unsuccessful. A planned program for four vessels in Vietnam was cancelled in 2016.