Türkiye launches sixth Istanbul-class frigate TCG Karadeniz at Sedef Shipyard.

On July 27, 2026, Türkiye launched its sixth Istif-class frigate, TCG Karadeniz (F-520), at Sedef Shipyard as part of the national MILGEM warship program. This launch demonstrates the execution of the parallel construction framework established between STM and the TAIS shipyard consortium to accelerate naval delivery cycles. Spreading hull production across multiple shipyards allows the Turkish Navy to shorten launch intervals and maintain concurrent outfitting streams prior to naval acceptance.

The 3,100-tonne TCG Karadeniz measures 113.2 meters in length and integrates a 16-cell Midlas vertical launch system alongside Havelsan's Advent combat management system and the Cenk-S AESA radar. Powered by a combined diesel and gas (CODAG) propulsion plant, the frigate reaches maximum speeds over 29 knots with an operating endurance of 5,700 nautical miles at 14 knots.

Related topic: Türkiye expands naval presence in Black Sea and Mediterranean with new İstif-class frigate TCG İçel

The İstif-class, which consists of eight frigates, will occupy the central layer of Türkiye’s future surface fleet between the smaller Ada-class corvettes and the future TF-2000 air defense destroyers (Picture source: Turkish Defence Agency)

On July 27, 2026, Türkiye launched the sixth Istanbul-class frigate, the TCG Karadeniz (F-520), at Sedef Shipyard, bringing the eight-ship programme closer to completion within the MILGEM national warship programme. The launch occurred 30 months after the December 2023 contract that extended serial production and 18 months after the TCG Akdeniz (F-519) was launched, indicating that construction intervals are shortening as work is distributed among several shipyards. The programme now comprises the TCG Istanbul in operational service, the TCG Izmir in sea trials, the TCG Izmit, TCG Içel, TCG Akdeniz and TCG Karadeniz launched and undergoing different stages of completion, and the TCG Ege and TCG Marmara under construction.

Seven of the eight planned frigates are therefore simultaneously in construction, fitting out or trials. That production profile shows that Türkiye is now able to sustain a serial production line with several ships advancing through different industrial and naval acceptance stages simultaneously. The first Istif-class frigate, the TCG Istanbul, was commissioned on January 19, 2024, three years after its January 23, 2021 launch, reflecting the lengthy integration and test cycle required for the first ship of a new frigate class. The TCG Izmir has progressed to sea trials, while the four subsequent hulls are in the post-launch phase, during which propulsion equipment, electrical networks, sensors, weapons, communications and command systems must be installed, connected and tested.

Anadolu Shipyard is responsible for the TCG Izmir and later hulls assigned to its production line; Sedef Shipyard has built the TCG Izmit and the TCG Karadeniz; and Sefine Shipyard has built the TCG Içel and is involved in subsequent work. Under the STM-TAIS arrangement, Anadolu, Sedef and Sefine were each assigned a frigate for simultaneous construction within a 36-month framework, replacing a sequential model in which one ship would absorb most available engineering and integration capacity before the next advanced. Parallel construction reduces the interval between launches, but it also requires three shipyards to maintain common construction standards, configuration control, supplier schedules and quality assurance across hulls that are nominally identical but may receive different equipment batches. 

The Istif-class, also known as the Istanbul-class or the I-class, is derived from the Ada-class corvette but is not simply a lengthened version of the earlier ship. Its hull measures 113.2 m, compared with about 99 m for the Ada-class, while beam is 14.4 m, draft is 4.05 m, and full-load displacement reaches 3,100 to 3,200 tonnes. The additional 14 m of hull length and several hundred tonnes of displacement provided enough space for a 16-cell vertical launch system, twice the Ada-class anti-ship missile load, expanded combat information spaces, larger accommodation and machinery compartments, additional fuel and a greater electrical load for radars, electronic warfare equipment and cooling systems. The frigate can therefore cover 5,700 nautical miles at 14 knots, equivalent to more than 10,500 km without replenishment under economical conditions, and can exceed 29 knots when operating with the gas turbine.

Speaking of which, its CODAG propulsion arrangement combines one General Electric LM2500 gas turbine with two diesel engines driving two controllable-pitch propellers. The diesels support sustained patrol and transit operations at lower fuel consumption, while the LM2500 provides the power required for high-speed interception, task-group manoeuver and repositioning. This gives the ship sufficient endurance for operations from the Black Sea and Eastern Mediterranean into the Red Sea, Arabian Sea or central Atlantic, although actual time on station will still depend on fuel reserves, sea conditions, maintenance requirements and access to replenishment ships. The combat system is built around Havelsan’s Advent Combat Management System (CMS), which combines radar, sonar, electronic warfare, communications, navigation and weapon control data into the tactical picture used by the operations room.

The principal air surveillance sensor is the Cenk-S AESA radar, which can track about 1,000 targets and has a maximum detection range approaching 400 km under favourable propagation conditions. The Akrep fire control radar provides precision tracking and weapon support, while the Alper low-probability-of-intercept surface-search radar detects ships and small surface contacts while reducing the probability that the frigate’s emissions are identified by hostile electronic support measures. The Fersah hull-mounted sonar provides the ship’s organic underwater search capability, but its effective coverage is conditioned by water temperature layers, salinity, ambient noise and the frigate’s own speed. The Ares-2N suite detects, classifies and geolocates radar emissions, while the Hizir provides torpedo warning and countermeasure functions.

A hangar and flight deck support one S-70B Seahawk and rotary-wing UAVs, allowing the TCG Karadeniz to extend its coverage beyond the limits of its sensors. The weapons fit gives the Istif-class substantially greater engagement capacity than the Ada-class and most earlier Turkish-built surface combatants. Sixteen Atmaca anti-ship missiles are carried in four quadruple launchers, allowing the frigate to conduct a larger salvo or retain weapons for multiple engagements. The ship’s 16-cell Midlas VLS can carry one larger missile per cell or four Hisar-D RF interceptors in each cell, producing a theoretical maximum of 64 Hisar-D RF missiles when the launcher is entirely configured for the quad-packed weapon. An operational load would more likely mix interceptor types balancing missile quantity, engagement range, target altitude and the need to counter aircraft, helicopters, cruise missiles and UAVs.

Siper Block-1 compatibility would extend the reach beyond point and local-area defense by providing a missile with a range exceeding 100 km, although the practical defended area would depend on the number of missiles allocated to the ship. The MKE 76 mm gun can engage surface craft, aircraft and coastal targets, while the Gökdeniz uses twin 35 mm guns and programmable ammunition as the final gun-based layer against missiles and drones. Two 25 mm remote weapon stations cover small boats and unmanned surface vessels at close range. Two twin 324 mm launchers can fire Orka lightweight torpedoes, whose stated speed exceeds 45 knots and whose range reaches 15 km, giving the frigate an onboard means of attacking submarines detected by the Fersah, its helicopter or another unit in the task group.

The I-class’s industrial importance lies less in a single domestic-content percentage than in the range of systems over which Turkish companies now control integration. The TCG Istanbul reached an estimated domestic-content rate of 80%, above the initial 75% objective, while about 80 subcontractors supplied more than 150 systems and roughly 220 companies participated across the programme. Turkish companies now provide the combat management system, surveillance and fire control radars, electronic warfare equipment, close-in defense system, anti-ship missiles, vertical launcher, air defense missiles, main gun, torpedo countermeasures and helicopter handling equipment.

National responsibility for these systems allows interfaces, software baselines and weapon configurations to be modified without relying entirely on a foreign combat system integrator. It also reduces the risk that a frigate becomes unavailable because an imported component cannot be replaced, updated or exported after a supplier government changes its licensing policy. Localisation does not eliminate external dependence, since the class still uses an American LM2500 gas turbine and foreign-origin components in propulsion, machinery and electronics, but the dependence is increasingly concentrated in individual subsystems rather than in the overall combat architecture. For the Turkish Navy, the Istif-class fills the gap between the smaller Ada-class corvettes and the future TF-2000 air defense destroyers, also known as the Tepe-class.

Türkiye’s projected surface force includes eight Istif-class frigates, four modernised MEKO 200 TN Track IIB frigates and eight TF-2000 vessels. The Istif-class can perform escort, anti-submarine warfare, anti-surface warfare and local air defense, but its 16 vertical-launch cells remain a constraint during sustained operations against repeated missile and UAV attacks. A ship configured with 64 Hisar-D RF missiles would maximise interceptor numbers but sacrifice space for larger weapons, while a mixed Siper and Hisar load would reduce the total number of engagements available before the frigate had to return to port for rearming. This magazine-depth issue explains why the class complements the planned TF-2000.

At the industrial level, Türkiye is estimated to have 10 to 15 major warships under construction for its own navy in 2026, placing it seventh behind China with 40 to 60 or more, the United States with 20 to 30, India and Russia with 15 to 20 each, South Korea with 12 to 18, and Japan with 10 to 15. When vessels for foreign customers are added, Türkiye’s combined workload rises to an estimated 20 to 30 ships, placing it fourth behind China, South Korea and the United States and ahead of Italy. That higher position is driven by a naval export portfolio distributed among several companies and shipyards rather than by one exceptionally large foreign contract. STM, TAIS, ASFAT, Dearsan and associated yards are simultaneously working on frigates, corvettes, offshore patrol vessels, landing ships, patrol craft and support vessels for customers including Pakistan, Ukraine, Malaysia, Indonesia, Nigeria, Qatar and Romania.

This differs from the business model of several European naval builders, whose export workload may be concentrated in one or two classes produced over longer periods. The Turkish model creates more concurrent hulls and spreads production across more yards, but it also increases schedule risk because engineering teams, radar suppliers, missile producers and combat system integrators must support several customers at once. The I-class is therefore both a domestic fleet project and an industrial workload stabiliser, maintaining engineering and production capacity that can be used for export ships and the larger TF-2000, MUGEM aircraft carrier or Atilay-class nuclear-powered submarines.

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.

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