Modernization of Turkish Submarines

In a significant development for the Turkish Navy, the inventory of Preveze class submarines is undergoing a half-life modernization project.

The Preveze Class Submarine Half-Life Modernization Project, initiated by SSB in 2016 covers the submarines TCG Preveze, TCG Sakarya, TCG 18 Mart, and TCG Anafartalar was launched and formally approved in 2017. On 8 February 2019, the Turkish defense acquisition agency SSB awarded a contract to STM, Havelsan, Aselsan, and Asfat partnership.

The Turkish Naval Forces operate eight Type 209/1400 class submarines. The first batch of four submarines was commissioned between 1994 and 1998. These four submarines are also known as Preveze class and have differences in equipment configurations from the later four. The mid-life modernization program covers both replacements of the existing ISUS combat management system by the MÜREN-Preveze combat management system developed by TÜBİTAK BİLGEM and the replacement of the older sensors and hardware by contemporary ones made by local companies. Both projects are separately contracted.

The main components to be replaced, overhauled, or updated during the MLU are the inertial navigation system, salinity-depth-density measurement system, floating antenna, telescopic SATCOM antenna, attack and navigation periscope, emergency communications system, cold water system and static converter, and air filtration system.

In February 2022, STM successfully completed the sea acceptance trials of the inertial navigation, salinity-depth-density measurement, cold-water systems, and static inverters, of the Preveze class mid-life upgrade project. Furthermore, the acceptance activities for these systems were concluded on March 2, 2023.

As part of the Preveze MLU, a  second contract for the installation of the MÜREN-Preveze combat management system was signed between SSB and  TÜBİTAK BİLGEM in August 2017. The first submarine integrated with the MÜREN-Preveze CMS is the submarine TCG Preveze. According to TÜBİTAK BİLGEM, the CMS can integrate data from 20 different sensors and navigation systems and can manage sonar signal processing, target movement analysis, and ship navigation. Furthermore, the CMS will be able to launch and control modern heavy-class torpedoes including the first domestic heavy-class torpedo Akya, developed by Roketsan.

In 2020 a shore-based development laboratory for the MÜREN CMS was opened inside the Turkish Navy’s research and development facility ARMERKOM. In 2021 the CMS and its consoles were integrated onboard the Preveze. The harbor acceptance tests were completed in late 2021. The sea acceptance tests are continuing.

In another significant development, STM has been assigned the platform integration responsibility for the Advent-Müren Combat Management System on the Gür class submarines. Through a contract signed between TÜBİTAK Bilgem and STM, the project aims to enhance the combat capabilities of these submarines. The Gür class submarines will be equipped with the national torpedo firing capability, enhancing their role in the defense. The modernization of the combat management system with national capabilities highlights Turkey’s commitment to strengthening its maritime presence.

The ongoing modernization efforts for Turkish submarines demonstrate the nation’s commitment to advancing its defense industry and embracing national technological advancements. Turkish local companies like STM play a pivotal role in supplying critical systems and undertaking platform integration highlighting their expertise in submarine engineering. As Turkey strives to increase its naval deterrence and bolster its maritime strength, these projects will undoubtedly contribute to the country’s security and the capabilities of the Turkish Naval Forces Command.

New ESM Sensor For Burak Class Corvettes

The above photo, taken in March 2018 shows TCG Bartın with her original ESM sensor on top of her mast. The below photo, taken in January 2023, shows TCG Bartın with her new ESM sensor.

The above photo, taken in March 2018 shows TCG Bartın with her original ESM sensor on top of her mast. The below photo, taken in January 2023, shows TCG Bartın with her new ESM sensor.

TCG Bartın was spotted fitted with a new set of electronic support measures systems this week when this ship made a port visit in Istanbul.

This was the first time that the Burak, (ex-Aviso) class corvettes fitted with this new and unnamed system. These ships were procured from the French Navy in the early 2000s.

A close-up view of the new ESM system.

A close-up view of the new ESM system.

While there is no publicly available information regarding this new ESM system, it is safe to assume that it was a labor of a collaboration between the Turkish Naval Forces and Aselsan. This outside sensor does not look like the one installed on board Ada and Meko 200 T1 class warships. Thus it must be specially designed to fit on the mast of Burak class corvettes.

This is not the first time that Aselsan has replaced a legacy ESM system on board a Turkish warship. In 2017, Aselsan started to replace the Signaal Rapids/Ramses ESM suit with a locally made one. That system was made of a new ESM sensor, dedicated or shared multi-function operator consoles, and a decoy launching system.

The new system installed on board TCG Bartın, has a new ESM sensor, as it was recognizable from the outside. I believe there will be a new dedicated or shared multi-function operator console inside the combat management center to display the data received by the sensors. To shorten the reaction time the decoy launchers are probably connected to the new ESM suite.

Existing Aselsan ESM systems have the capability of detecting, intercepting, identifying, classifying, tracking,  direction finding, localizing, platform correlating, and recording electromagnetic emissions.

This new system will without a doubt increase the ship’s situational awareness and enable the crew to make more informed decisions.

Electronic Warfare Exercise With Unmanned Vessels

This week, Turkish Naval Forces conducted an electronic warfare exercise off the coast of Antalya.

The embedded short video shows ULAQ unmanned surface vessel with an EW suite and antenna. This version of ULAQ was made public when it was shown to the members of the Ankara Military Attache Corps.

The details of the new configuration have not been shared with the public. However, on the panel The Future of Unmanned Naval Systems and Turkey’s Potential held during the SAHA Expo last week, it was reviled that the Sefine Shipyard – Aselsan joint venture the Merlin USV was also in Antalya.

The Merlin took part in REPMUS 22 and Dynamic Messenger 22 exercises held at the Maritime Operational Experimentation Center (CEOM) in Troia, Portugal.

Besides the USV, there was one Yavuz class frigate, one Ada class corvette, and one Kılıç class fast attack craft participating in the exercise.

The presence of two especially for electronic warfare configured unmanned surface vessel indicates that the Turkish Navy is spending time learning the potential of these vessels closely and developing concepts to use these vessels in action.

One Ada class corvette in the background and one Yavuz class frigate off the coast of Antalya during the electronic warfare exercise. Photo: Mert Şekersoy. Used with permission.

Testing Of DÜFAS Sonar System Has Started

TCG Sokullu Mehmet Paşa. Note the Gökdeniz CIWS turret has been replaced with other equipment. Photo: Oğuz Eroğuz.

The detail equipment installed on board of TCG Sokullu Mehmet Paşa. Photo: Oğuz Eroğuz.

The detail equipment installed on board of TCG Sokullu Mehmet Paşa. Photo: Oğuz Eroğuz.

The Turkish Navy started to test a new towed sonar array on board of TCG Sokullu Mehmet Paşa.

Previously the Rhein class auxiliary ship was used as the test bed for the Aselsan made Gökdeniz CIWS system. Photos, recently taken show that the Gökdeniz CIWS turret was removed from the ship. The aft of the ship is now occupied with a metal shelter, one large cable spool a winch and some davits like metal construction.

It was previously reported that the testing of the DÜFAS towed array system would commence in 2022. While the initial reporting mentions the test would be conducted on board of a Gabya class frigate, it is possible that these tests are now conducted on board of TCG Sokullu Mehmet Paşa as the photographic evidence suggests.

DÜFAS is a towed low frequency active sonar project initial by the Research and Development department of SSB and being developed by Aselsan, Armelsan and Nanotech.

New Sensors For Gabya Class Frigiates

A photo of TCG Gaziantep with the new electro-optic sensor. Photo: Oğuz Eroğuz. Used with permission.

The Turkish Navy started to upgrade the Gabya class frigates with a new electro-optic sensor.

The sensor was first observed on board TCG Gökçeada a couple months ago, the new electro-optic sensor appeared on board TCG Gaziantep this week. The ship was in overhaul. The E/O seems to be installed on a special pedestal on top of the bridge.

While there are no official announcements either from the Turkish Navy or Aselsan the system used on board seems to be the Denizgözü-Ahtapot version.

According to Aselsan Ahtapot is an E/O reconnaissance and surveillance system. The system has high-performance IR, HDTV and Spotter cameras, and an eye-safe laser range finder.

The sensor was specifically designed for naval use on board large ships. The first ship it was installed was on TCG Burgazada.

The lack of a dedicated E/O reconnaissance and surveillance system on board Gabya class frigates was an important shortcoming. With the installation of Ahtapot E/O, this shortcoming will be rectfied.

The Keel Of The Bulgarian Corvette Laid In Varna

A model of the Hrabri. Photo: MTG Dolphin

On 17th June 2022, the keel of the first of two new Multipurpose Modular Patrol Vessels (MMVP) for the Bulgarian Naval Forces was laid with a ceremony. The vessel is named  Hrabri, meaning “Brave” in Bulgarian.

The procurement of modern surface combatants to meet NATO Requirements were in consideration for a long time. These new MMVP’s will replace two Pauk (Project 1241P) and one Tarantul (Project 1241.1M) class corvettes.

While the details of information such as the armament, sensors and specifications have not been made public yet according to NVL, the vessels, which are around 90 meters long, with around 2,300 tons of displacement, are based on the proven OPV 90 design from the NVL portfolio and feature an integrated Combat Management System. The Swedish company SAAB announced in December 2020 that it was going to provide the combat management system for these ships.

The ships are going to be armed with one 76mm main gun furthermore four -probably European-made- anti-ship missiles, eight VL-MICA anti-aircraft missiles in vertical launcher cells, one Rheinmetall Millenium close-in weapon station, and lightweight torpedoes are among the weapons. The MMVP’s are going to be the first ships in Bulgarian Naval forces with a flight deck and a hangar and they will be able to accommodate the AS-565MB Panther naval helicopter in Bulgarian service.

The total volume of the MMPV project is around 420 million euros. Delivery of the first vessel is scheduled for the third quarter of 2025, and the second vessel a year later. The construction of the second ship will begin in early 2023.

It was high time for Bulgaria to invest in its naval forces. These are the first new warship constructions for the Bulgarian Navy for over a century.

Today Ukrainian Armed Forces are using Switchblade loitering ammunition from the USA, CAESAR self-propelled guns from France and NLAW anti-tank missiles from the UK successful again the invading Russian forces. None of these weapons was in the Ukrainian inventory at the start of the war. Ukraine and its Allies were able to deploy these weapons, train their users efficiently and field them against the enemy in a period of mere weeks.

Unfortunately, navies do not have this type of luxury. It takes a few years to build a new warship but takes generations to establish a coherent naval fighting organization. Even if one of the Allies of Ukraine would have donated one or more warships to help bolster Ukrainian naval Forces it would take months to properly train the sailors to efficiently use all the systems on board.

It is time for investment in naval forces. If Ukraine has a more capable naval force with larger ships carrying more sting it could have been easier to arm them with alternative weapon systems to counter the Russian blockage against the Ukrainian ports.

Unlike Ukraine, Bulgaria has the luxury of being a member of NATO. While NATO membership may provide a country with a fair amount of protection and security, it is never a substitute for investing in its own armed forces.

First Steel Cut For The New OPV


The first steel is cut for the Turkish Navy offshore patrol vessel Akhisar on 9 April 2022.

The OPV is being developed by Asfat and is based on the Milgem class corvettes. By using the hull of the Milgem class ships the OPV will be built in a shorter time and at a lower cost.

The OPV will have a very different main propulsion system from the Ada class corvettes. These ships will have a combined diesel-electric or diesel engine combination (CODELOD). This combination will give the ships a cruising range of 4500 miles and an economical speed of around 15 knots with very low fuel consumption. The crew will be 104.

According to Asfat these OPVs will be built with the fitted for but not with design philosophy, which will allow the integration of newly developed national weapon and sensor systems.

Aselsan Gökdeniz CIWS System Will Be Tested On Board TCG Sokullu Mehmet Paşa

Today the Rhein class auxiliary ship, TCG Sokullu Mehmet Paşa, left her homeport in Tuzla, İstanbul and headed to the Black Sea.

TCG Sokullu Mehmet Paşa and her sister TCG Cezarli Hasan Paşa have two 100mm gun turrets. The aft turet on board of TCG Sokullu Mehmet Paşa was removed in 2018. She was used as test ship for the Aselsan made close in weapon system Korkut-D in May 2018.

After the completion of these tests, the Korkut-D mount and the associated hardware was removed from the ship.

Today TCG Sokullu Mehmet Paşa was spotted with a new gun system installed. While the whole gun system and the associated radars and other sensors were under wraps the shape of the system is very distinguishable. The system to be tested is the Gökdeniz close-in weapon system.

Gökdeniz consists of one unmanned gun turret with two 35mm guns, an X band 3-D tracking radar and one fire control radar with electro/optical sensors. All subsystems of the Gökdeniz system are recognizable on board.

The gun turret has been remodelled from her initial version making it suitable to be retrofitted in place of the existing CIWS systems on board. The guns can use the ATOM 35mm airburst ammunition developed by ASELSAN. ATOM is a smart ammunition, having a base fuze increasing the effectiveness of the barreled guns. Thus such ammunition is an important option to fight against small and high-speed targets.

The X band tracking radar has a range of 100km. With its phased array, multi-beam antenna the radar can track multiple air targets simultaneously.

The Gökdeniz close-in weapon system will be installed onboard Barbaros class frigates during their mid-life upgrade, İ class frigates and in the future other ships.

Converting LHD Anadolu To A Drone Carrier

Prologue: This article was first published in Defence Turkey Magazine Issue 106.

It is not a secret that Turkey intends to operate an aircraft carrier. This desire was made public by President Erdoğan during his speech at the launching ceremony of the frigate TCG Istanbul.

The interest of Turkey to operate airplanes from a large ship with a big flight deck is not new. This is a lesson learned from the big humanitarian assistance operation in Libya. Between 19 February and 4 March 2011, Turkey evacuated 23.127 persons from Libya fleeing from the fighting in the country. 8.351 evacuees were transported by sea. The need for a large amphibious ship with a large flight deck and a dock becomes very apparent during this Non-Combatant Evacuation Operation. During the evacuation, a few times, F-16 fighter planes of the Turkish Air Force had to be flown from Turkey to Libya to provide airpower, an operation requiring multiple in-flight refuelling. Despite all the hardship and the cost of flying land-based F-16 fighters from Turkey to Libya their time on target was not adequate and they were not available on short notice. These operations showed the niceties of having an organic air force for the Turkish Navy.

In 2015 the Turkish defence procurement agency Savunma Sanayi Başkanlığı announced that Spanish Navantia’s solution for a large amphibious assault ship was chosen after a long tendering process. The ship is based on Navatia’s Juan Carlos LHD design and is very similar to SPS Juan Carlos 1 in Spanish and, HMAS Canberra, HMAS Adelaide in RAN service. The construction of the ship named Anadolu started in 2016. When finished Anadolu will be the largest ship in Turkish Navy inventory and the first Turkish naval platform where multiple helicopters can launch and land at once and fixed-winged air vehicles can operate. Anadolu will provide a unique experience and platform for the Turkish Armed Forces.

The ousting of Turkey from the F-35 Lightning II Joint Strike Fighter Program has forced Turkey to change its plans. Turkey was a member of the F-35II Lightning fighter plane program for the start and wished to buy around 100 land-based F-35A versions for the Turkish Air Force. Later it was decided to buy a modest number of vertical and/or short take-off and landing (V/STOL) variant F-35B to be used onboard Anadolu. 6 to 8 planes deployed on board would provide air cover and perform strike missions during amphibious operations. Since the ship was designed to accommodate and operate Harrier in Spanish service it would be F-35 compatible with little changes. However, the ousting of Turkey from the F-35 Lighting II program made all these plans redundant. Necessity is the mother of invention. Thus, alternatives for F-35B are under consideration. There are two realistic options available for the Turkish Government and the Navy. The first is to convert the Anadolu, to accommodate unmanned combat aerial vehicles.

In March 2021 the president of the Savunma Sanayi Başkanlığı, Prof. İsmail Demir told that work was done to deploy unmanned combat aerial vehicles from Anadolu. Both the Sedef shipyard where the ship is constructed and Baykar Makina, one of the leading drone manufacturers, are conducting studies for this end. Selcuk Bayraktar, the CTO of Baykar Makina has announced that they are working on a new unmanned combat aerial vehicle TB-3 which will be able to be operated from Anadolu. The TB-3 is expected to start test flights in 12 months. It will have a maximum take-off weight of 1200 kg and will carry heavier ammunition compared to the contemporary UCAV, Bayraktar TB-2. To withstand the rigours of landing on a noticeably short and constantly moving flight deck the TB-3 will have a reinforced airframe and landing gear. TB-3 is believed to have foldable wings to make it easier to move on the flight deck and inside the hangar.

Currently, it is not clear whether Anadolu can accommodate the future UCAV in her current design or changes are needed. If structural changes are needed, these may further postpone the delivery of the ship. And if any changes are needed the redesigning of the hip will be performed by Sedef Shipyard as Navantia who has developed the original ship design has finished its contractual obligations.

While operating UCAV will be easier and probably safer than operating a manned system never the less it will be a novel concept and will be a unique experience with its own challenges. The Bayraktar TB-3 UCAV will enhance the air to ground mission capabilities. However, air defence and air-to-air operations missions will still need land-based manned fighters or ground-to-air weapons and good sensors on escorting ships.

Another option to deploy planes on board Anadolu is to redesign the Hürjet advanced jet trainer and light attack craft for carrier operations. Hürjet is a single-engine, tandem seat aircraft under development by Turkish Aerospace TAI. During the above-mentioned interview, Mr. İsmail Demir mentioned that discussions between SSB and TAI were held on whether Hürjet can be used on Anadolu. He also told that some design changes were carried out, some simulations were made and it has been concluded that the design can be modified to make Hürjet operate from a ship such as Anadolu. Adapting the ship and Hürjet planes for each other will be more challenging than developing new armed drones for shipborne operations. An important factor to be considered is the shape of the flight deck of Anadolu.

The flight deck of Anadolu is in a rectangular shape with a large island structure on the starboard side and a 12 degree Ski jump at the front. There is a large aircraft elevator at the very aft of the flight deck. In its current form, the flight deck resembles the flight decks of old aircraft carriers from 2. World War. The arrangement was acceptable as long as the planes had a low landing speed and were light although it was not without its hazards. However, when the planes got faster due to jet engines and heavier a rectangular flight deck arrangement was not safe or sufficient to sustain operations. Thus in the early 1950’ies, Royal Navy devised the angled flight deck. In this configuration, the flight deck has an angle of 6 degrees. This allowed the landing plane to roll away from the planes on the catapult waiting for launching. Ever since all modern aircraft carriers of all nations -with the exception of carriers specially designed for the Harrier S/VTOL planes- have an angled flight deck.

Anadolu does not have an angled flight deck. Thus, in her current form, she is only suitable for planes that can launch using a ski jump and land vertically or land in a very short distance. If Hürjet planes are to be configured to be used onboard Anadolu these planes need to be resigned radically. This will cost time and money. And the end result may not be satisfactory as it is very risky engineering work. A more realistic approach would be while modifying Hürjet for naval operations to design a new ship with a suitable launch and recover facilities that are suitable for navalised Hürjet. From an engineering point of view, this scenario is far more likely to be successful. But then again it will cost time and money and the planes will not be compatible with Anadolu.

Of course, one can always suggest buying a second-hand ship as an alternative. However, I believe that this road is a dead-end though Turkey has been looking for this option. Even when the construction of Anadolu was progressing, in 2017, Turkey showed interest in the ex-Royal Navy helicopter carrier HMS Ocean when she was decommissioned from Royal Navy service. The ship was not new and had extensive service in Royal Navy but never less someone thought the purchase of HMS Ocean would have increased the strength of the amphibious capabilities Turkish Navy and added new capabilities.

Head of Bahçeşehir University, Maritime and Global Strategies Center, Retired admiral Cihat Yaycı, told in March 2021 that the Turkish Navy should convert the decommissioned aircraft carrier ex Foch, ex São Paulo back to active service. The ship was bought by a Turkish scrapyard in March 2021 and will be towed from Brazil to Turkey. The ship started her life as French aircraft carrier Foch in 1963 and served in French Naval Forces until 2000. After years of arduous service under the French flag, she was sold to the Brazilian Naval Forces and renamed as NAe São Paulo. This old lady served 20 years in Brazil. After a major fire killing 3 crew members, the ship was extensively overhauled between 2005 and 2010. São Paulo was expected to rejoin the fleet in late 2013 but suffered another major fire in 2012. As of September 2016, she continued to undergo repairs, the commander of the Brazilian Navy, Admiral Eduardo Leal Ferreira, said plans were in place to renew the carrier’s propulsion system. The ship’s catapult was also reported to have problems.

Mr. Yaycı believes that the Turkish Navy should acquire the ship. After refurbishing her back into working condition, the ship can be used for training and system familiarization purposes.

The old French carrier operates like US Navy carriers catapult to launch airplane and arrester wires to slow landing planes. Neither Turkish Naval Aviation nor Turkish Air Force operates airplanes that are suitable for operations from a carrier and Turkey’s prospects to obtain such planes from abroad seems to be almost nonexistent. The idea of refurbishing this old and worn-out ship back to active service is absurd time consuming and very costly. Time and money are two luxuries Turkey cannot afford to misspend. Warships like any ship is a living system consisting of their crew, her equipment, systems and subsystems on board. Learning of the working of an organism is best done when one observes a living one and to through autopsies. Thus, posting Turkish naval officers as liaisons on board the aircraft carriers of our NATO partners is a better way of learning about the multiple aspects of operations onboard rather than dissecting the cadavers of decommissioned aircraft carriers sent to break yards in Aliağa.

Epilogue: During an interview in December 2021, Mr. İsmail Demir told the reporters that the primary aim was to commission the Anadolu into the Turkish Navy in her original design. When the carrier-borne drone TB-3 is materialised, the adaptation of these unmanned planes into the ship will be revised.

Serial Production Line Qualification Test Of Atmaca Missile

Turkish Navy conducted another live firing of Atmaca anti-ship missile on 18th June 2021.

The test was conducted again at the live-fire exercise area off the coast of the Black Sea town Sinop. The last of the Ada class corvettes, TCG Kınalıada had the honour to do testing. At the receiving end of the missile was this time not a target barge but decommissioned salvage and submarine rescue ship Işın.

The missile used was, assumed to be the first missile from the serial production line. Here are some screen captures from the videos published from the test.


This photo shows Atmaca right before impacting the target ship. The missile is capable of flying very low, making it difficult to differentiate from clutter and engage.

The missile hit the target amidships in the area marked in red. The hole is just above the water level.

The initial videos shared from the test ended when the missile hit the ex Işın, leaving enthusiasts wondering about the size and location of the damage. However, videos showing the damage submerged shortly after.

There is even a video showing the damage the missile has created inside ex Işın. This means that the ship did not sink immediately after the impact. There was enough time for some to go onboard and survey the damage from inside. That is reasonable as ironically it is more difficult to sink an empty ship than one in active service. The striped down hulls have nothing on them. No fuel, no ammunition no warheads or any incendiary material which may create secondary explosions and spread the fire.

When the serial production starts the Atmaca missile will replace the Boenig Harpoon missiles on Turkish warships probably on a one-to-one basis. This will need some changes in combat management systems to incorporate the new missile into existing software. The Ada class corvettes are the most likely candidates as the Genesis CMS is made by Havelsan. Thus this CMS is the easiest one to add the Atmaca. The next ships equipped with Atmaca might be the Barbaros class frigates that will receive the mid-life upgrade program or the Istanbul class frigates whichever comes first. Both classes of ships will again locally developed CMS making it very easy to add the new missile.

Ever since the long-range anti-ship missiles replaced the guns as the main offensive weapons, having total control and command on every aspect of this weapon has become vitally important for the war-fighter. By replacing the foreign missiles with local ones Turkish Navy will be able to trust that its punch will find its mark.

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