GÜRDESAN Submarine Projects: Section 50 and Test Tunnel
Quick answer: GÜRDESAN’s role in submarine projects is the company’s most significant reference in the Turkish defence industry. Section 50 — the torpedo tube section housing the main weapon systems of the Reis-class submarines — was produced in Turkey for the first time at the Gürdesan Shipyard in Yalova under STM’s engineering and coordination, and was delivered to the Gölcük Naval Shipyard Command in September 2021. In 2016 the company had also fabricated the internal blocks of the same programme, and it built the ITU Large Cavitation Tunnel where propellers and submarine models are tested.
What is Section 50 and why does it matter?
Section 50 is the bow section of the Reis-class (Type 214TN) submarines that houses the torpedo tubes and the systems enabling guided missile launch. According to a September 2021 report by Anadolu Agency, only a small number of countries can produce this section. The Section 50 units of the programme’s first two boats (Pirireis, Hızırreis) were built by ThyssenKrupp Marine Systems in Germany; from the third boat, TCG Muratreis, onwards, production was transferred to GÜRDESAN under STM coordination. Production of the third boat’s section began in 2018; the completed section passed its acceptance tests and was transported by sea to Gölcük in 2021. Industry media reported the section as weighing roughly 180 tonnes and measuring about 12 metres in length.
Division of work in the project
| Task | Organisation | Source |
|---|---|---|
| Programme execution (New Type Submarine Project) | Presidency of Defence Industries, Gölcük Naval Shipyard Command | AA |
| Engineering and coordination | STM | AA, DefenceTurk |
| Section 50 fabrication (from the third boat) | GÜRDESAN (Yalova shipyard) | AA, Denizhaber |
| Section 50 units of the first two boats | ThyssenKrupp Marine Systems | AA |
| Internal block fabrication (2016) | GÜRDESAN | Denizhaber |
ITU Large Cavitation Tunnel (KATMANSİS)
The company’s second contribution to the submarine ecosystem is test infrastructure. The Large Cavitation Tunnel, whose hydrodynamic design was developed jointly by Poland’s CTO and Istanbul Technical University, was manufactured by GÜRDESAN using domestic means and opened on 17 December 2021. According to MarineDeal News, the tunnel’s test section measures 5.5 x 1.5 x 1.2 metres; it can run experiments at flow speeds of up to 16 m/s and ranks seventh in the world by test-section flow rate. Torpedo projects as well as new type submarine and propeller models are tested in the tunnel. This work is directly linked to the company’s engineering base in steering and propulsion systems.
Other military items in the catalogue
GÜRDESAN’s listing in the industry catalogue of the Presidency of Defence Industries includes — alongside the Section 50 torpedo bow block and the submarine internal blocks — items such as a submarine personnel rescue bell, a heavy machine gun mount, a replenishment-at-sea winch, a spanwire winch, a RHIB boat winch and tank and vehicle beaching gear. There is no official statement on which naval programmes these items serve; for that reason, this file details only the work verified by independent sources. The company’s civilian product groups are covered in the products guide, and its corporate structure in the Who owns GÜRDESAN? file.
What localisation means for the programme
The New Type Submarine Project is based on licence-built construction of the German Type 214 design in Turkey; one of the programme’s goals was to shift sections and systems imported for the first boats to domestic production in later boats. In statements reported by AA, STM General Manager Özgür Güleryüz said that 33 systems had been localised across the programme and that 19 domestic suppliers were involved; Section 50 fabrication is one of the most visible links in that chain. For GÜRDESAN, the technical challenge lay in the fact that the section, welded to the pressure hull, must both withstand pressure at diving depth and align with millimetric precision with the torpedo tubes’ launch systems; both AA and industry media reported that the acceptance tests were passed without fault. Industry reports also wrote that the company invested in a large 11-axis CNC machining centre acquired from Czechia for this work, with the machine credited with large-part machining capacity; this is a media report, and no official technical document has been published by the company. As a continuation of domestic production, the Section 50 units of the fourth, fifth and sixth boats were also planned for the same line.
Frequently asked questions
For which submarines was Section 50 produced?
The first Section 50 produced in Turkey was integrated into the third boat, TCG Muratreis; according to AA, production was also planned for the sections of the fourth, fifth and sixth boats.
Why can so few countries produce Section 50?
The section requires integrating the torpedo tubes and launch systems into the pressure hull to millimetric tolerances; the AA report notes that few countries in the world hold this capability.
Does GÜRDESAN build the whole submarine?
No. The submarines are built at the Gölcük Naval Shipyard Command; GÜRDESAN is the subcontractor that produced the Section 50 and the internal blocks under STM coordination.
What is the cavitation tunnel for?
The tunnel is research infrastructure for flow, cavitation and hydroacoustic testing of propeller, torpedo and submarine models; it is installed at Istanbul Technical University.
Did GÜRDESAN take part in MİLGEM or TCG Anadolu?
There is no officially disclosed information on direct equipment supply to these programmes; the verifiable military references are concentrated in the submarine programme and test infrastructure.
Sources and verification note
Section 50 information was verified from AA and independent industry media, and the cavitation tunnel information from MarineDeal News; weight and dimension figures are given as media reports, and catalogue items without programme attribution are given at list level only. Accessed: August 13, 2026.
- https://www.aa.com.tr/tr/bilim-teknoloji/denizaltilarin-torpido-kovan-bolumu-ilk-kez-turkiye-de-uretildi/2364475
- https://www.savunmasanayist.com/reis-sinifi-denizaltilarin-torpido-kovan-bolumu-ilk-kez-turkiyede-uretildi/
- https://www.denizhaber.net/turkiyede-uretilen-ilk-section-50-golcuk-tersane-komutanligina-teslim-edildi-haber-104079.htm
- https://www.defenceturk.net/turkiyede-ilk-kez-denizaltilar-icin-section-50-uretildi
- https://www.denizhaber.net/gurdesan-gemi-makina-a-s-yonetim-kurulu-baskani-mustafa-gursoy-vefat-etti-haber-101313.htm
- https://www.marinedealnews.com/katmansis-kullanima-acildi/
