Turkish shipbuilder STM Savunma Teknolojileri Mühendislik, ve Ticaret A.Ş, has achieved significant project milestones in constructing and modernizing the Turkish Navy’s Preveze-class and Gür-class submarines. Completing these milestones marks a crucial step forward in enhancing the capabilities of the Turkish Submarine Fleet.
The Preveze-class Submarine Half-life Modernisation (PREVEZE-YÖM) Project, initiated by the Presidency of Defense Industries (SSB), has reached another noteworthy milestone. Following successful sea acceptance trials of key systems, including the inertial navigation system, CTD probes, cooled water systems, and static inverters, STM received approval from the SSB on March 2, 2023.

Under the PREVEZE-YÖM project, STM secured a contract in 2022 for the modernization of four Preveze-class submarines, namely TCG Preveze (S-353), TCG Sakarya (S-354), TCG 18 Mart (S-355), and TCG Anafartalar (S-356), which are currently part of the Naval Forces Command’s inventory.
As the leading partner in the project since February 8, 2019, STM has been responsible for supplying nine systems and undertaking platform integration works. The company’s expertise and diligent efforts have contributed to successfully completing acceptance tests for four systems under the PREVEZE-YÖM Project.
In another significant development, STM signed a contract with TÜBİTAK Bilgem in February 2023. This contract entails the platform integration of the Advent-Müren combat management system on Gür-class submarines. The collaboration between TÜBİTAK Bilgem and Naval Forces Command aims to enhance the combat capabilities of Gür-class submarines through the Advent-Müren combat management system and AKYA Integration project.
Integrating the Advent-Müren combat management system on Preveze- and Ay-class submarines has already enabled these vessels to possess the national torpedo AKYA firing capability. As part of the contract signed between TÜBİTAK Bilgem and Naval Forces Command, the Gür-class submarines will be modernized with the indigenous combat management system and equipped with the AKYA firing capability.
Özgür GÜLERYÜZ, General Manager of STM, expressed confidence in the company’s capabilities, stating, “Our qualified workforce and technologies allow us to carry out significant projects related to the submarine platforms of the Turkish Navy and those of friendly and allied nations. Among these is the PREVEZE-YÖM Project, under which we have completed the acceptance tests of four systems. We have now signed a new contract with TÜBİTAK BİLGEM to transfer the engineering experience gained in the Ay- and Preveze-Class submarine modernization projects to Gür-Class submarines.”
STM has played a crucial role in the Turkish Navy’s submarine modernization and construction projects. In 2015, as the main contractor, the company completed the modernization of two Ay-class submarines. Additionally, STM has been the main contractor since 2016 in the modernization of the French-made Agosta 90B Khalid-class submarines owned by Pakistan. The delivery of the first two submarines under the Agosta 90B Modernization project has been accomplished, and STM is currently continuing the modernization works on the third submarine for Pakistan.
With the completion of these project milestones, STM has demonstrated its commitment to advancing the capabilities of the Turkish Navy’s submarine fleet, contributing to national defence and strengthening international partnerships in naval.