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STM`s Design for the Turkish Type Fast Attack Craft Project

The Turkish Type Fast Attack Craft (FAC) Project was initiated in 2013 by the Presidency of Defense Industries (SSB) in order to destroy/neutralize enemy elements and to ensure the survival of its own elements. Within the framework of the Turkish Naval Forces Command (TNFC)’s mission of sea surveillance and control in its theater of operations, the Term-I Agreement Design Contract for this project was signed on August 31, 2020 between the SSB and the main contractor STM Savunma Teknolojileri Mühendislik ve Tic. A.Ş.

Issue 104

The information shared on the projects section of STM's website on December 14, 2020, regarding the Turkish Type Fast Attack (FAC) Project Term-1 Agreement Design Contract includes the following:

“Within the scope of the contract to be executed by the main contractor STM, the identification of system requirements of the Turkish Type Fast Attack Crafts, concept selection, preliminary design and contract design activities will be carried out. Throughout the project, Indigenous Design development activities (Ship Hull Form Optimization, Ship Structural Analysis, Main Propulsion System, Ship Electrical System Design and Weapon Configuration) and the relevant design package will be developed.”

As mentioned above, the Term-I Contract is merely for the design process and a separate contract will be signed for the construction process. As per the information we have obtained, STM will propose multiple designs that will contain a series of variations in terms of both the propulsion system and weapon system under the Term-I Agreement Design Contract with a schedule of 24 months. Upon the selection of one of these designs proposed by the SSB and the Turkish Naval Forces Command (TNFC), the 30-month Term-II Prototype Construction Contract will then be signed, and the first boat will be built at a shipyard deemed appropriate (at this point, I think the prototype boat will be built at MSB Istanbul Shipyard). Thus, the first boat of the Project will have been delivered to the TNFC within 54 months. For the time being, it is not clear, whether the Project will be carried out by the main contractor STM after the Term-I Contract, as in Test and Training Ship (TVEG) and İSTİF Class Frigate Projects, or if the construction process will be given to a private sector shipyard as in the DIMDEG Project after the design process (SEFINE Shipyard was selected for the DIMDEG Project).

Within the scope of the Turkish Type FAC Project on which STM has been working for a long time and to which it has placed great importance, STM developed a design named FAC-55 (FAC is the abbreviation of the English initials of the Fast Attack Craft, 55 symbolizes the speed the boat can achieve) and conducted the necessary pool tests. In the test activities conducted by internationally recognized institutions, STM proved that it has designed a naval platform that performs effectively up to a speed of 55+ knots.

During the Term-I Contract, I think the alternatives of the main propulsion system and weapon configuration in boats will be considered pursuant to the CAATSA sanctions imposed in mid-December 2020 as well as the embargoes placed for several years, and the foreign-origin weapon and sensor systems in the FAC-55 design that was developed five years ago will be replaced with indigenous design products (for example, MKEK's 76mm gun instead of Leonardo DRS/Oto Melara 76mm gun; ATMACA B1/B2 or Medium Range Anti-Ship Missile (OMGS) Anti-Ship Cruise Missiles instead of RGM-84L Harpoon Block II; GÖKDENİZ CIWS, SUNGUR PMADS or SAPAN/HİSAR-A+ Systems instead of the 21-cell Mk49 Mod 3 Launcher and RIM-116 Block IA/HAS missiles). In addition, I think the alternatives of gas turbine, which was previously selected from the COGAG (Combined Gas Turbine and Gas Turbine) architecture, will also be considered for the main propulsion system, again pursuant to the ITAR/CAATSA sanctions.

Turkish Naval Forces & FACs 

A fast attack craft (FAC) is a small, fast, agile and offensive warship armed with anti-ship missiles and/or torpedoes. FACs have low tonnage but high maneuverability. In size they are usually between 50–800 tons and can reach speeds of 25–50 knots. FACs are usually operated in close proximity to land as they lack both the sea-keeping and all-round defensive capabilities to survive in blue water. Their high speed and small size make them the best alternative for assault operations. These boats, which are fully armed in contrast to their size, are cost efficient. Thanks to their high speed, such boats are able to move quickly from one point to another and keep the target under control in a very short time. As a critical part of the war concept in coastal waters, FACs are the most effective platforms that can be used in the Aegean Sea.

Built by Breda in Venice, Italy in 1930, Doğan, Martı and Denizkuşu were the first FACs of the Republic Period which were brought to Turkey on the deck of a merchant ship and launched to service on September 15, 1931. The DOĞAN Class Guided Missile Assault Ship Project was initiated with the German Lürssen Shipyard in early 1970s. The first ship TCG Doğan (P-340) started to be built in Germany on June 15, 1974 and was placed into service on December 23, 1977. The other seven assault ships, namely Martı, Tayfun, Volkan, Rüzgar, Poyraz, Gurbet and Fırtına were built at İstanbul Taşkızak Shipyard and put into service in 1978-1988. The last ship, TCG Fırtına started to serve on June 22, 1988. Later, the first four ships were categorized as DOĞAN Class, and other four as RÜZGAR Class. The RGM-84 Harpoon  Anti-Ship Guided Missile started to be used for the first time in the Naval Forces’ assault ships with the launch of DOĞAN Class, moreover, the first Harpoon Anti-Ship Missile in the history of the Turkish Naval Forces was fired by TCG Doğan. Then a new agreement covering the construction of an additional five ships with Lürssen was made in 1991 and in line with this agreement, YILDIZ Class TCG Yıldız (P-348) and TCG Karayel (P-349) FACs were built once again at the Taşkızak Shipyard with a different design and entered service on May 23, 1997. Due to the design-related problems arising in these ships and also to keep up with technological trends, the project was finalized with the 2nd ship TCG Karayel and KILIÇ Class Assault Ships (9th generation FACs that serve the Naval Forces) started to be built. The first ship, TCG Kılıç (P-330) was built at the Lürssen Shipyard in Germany, TCG Kalkan (P-331) and TCG Mızrak (P-332) at Taşkızak Shipyard. KILIÇ-I Class Assault Ships entered the service of the Naval Forces in July 1998, July 1999 and June 2000, respectively. The radar cross sections of these ships were designed to minimize their radar reflections.

KILIÇ-II Class is the follow-up of its predecessor KILIÇ-I Class Guided Missile Assault Ships, yet the 76mm naval gun was quite different and they were built to feature a reduced radar cross section signature in their hull and upper deck design. The KILIÇ-II Project Agreement covering the assault ships, which were more modern than the KILIÇ-I particularly in terms of sensors and systems, was signed between the Ministry of National Defense and Lürssen Werft on June 19, 2000, for four ships initially. The contract volume of these four ships was EUR 379 Million (US$ 477 Million). With the addendum to the contract signed on July 17, 2001, two more ships for EUR168 Million (US$ 211 Million) were added. TCG Tufan, the first ship, was built in Germany. Out of the five assault ships built in Turkey, three were built at the Istanbul Shipyard Command and the remaining two were constructed at the Gölcük Shipyard Command.  Due to the propulsion system, with a capacity of 22,000hp and composed of 4 MTU main engines, 4 propellers and two rudder blades, KILIÇ-I/II Class Assault Ships are able to reach a maximum speed of 42 knots and a continuous speed of 39 knots. The youngest ship of the KILIÇ-II Class, that is the most modern assault ships currently serving the Naval Forces, is over ten years old. The number of the assault ships built both in Germany and Turkey under Lürssen Werft license reached 35, including DOĞAN Class’ fourth generation KILIÇ-II Class ships. Presently, a total of 19 Assault Ships comprising 4 DOĞAN Class, 4 RÜZGAR Class, 2 YILDIZ Class, 3 KILIÇ-I and 6 KILIÇ-II Class ships are serving the Naval Forces.

Within the scope of the KASUMSİS Project, the contract of which was signed in 2015, Aselsan’s 3-axes stabilized X-Band satellite communication system (SatCom) was integrated to KILIÇ-I and KILIÇ-II Class Assault Ships. Whereas, as part of the Ku-Band Satellite Communication System Project, the Ku-Band satellite communication system terminal manufactured by Aselsan was integrated to DOĞAN, RÜZGAR and STAR Class Assault Ships. Modernization activities for the Alarm and Monitoring and Power Management Systems of the KILIÇ-I Class Assault Ships are performed by YALTES. TCG KILIÇ was equipped with the new generation PIKET 3000® Integrated Platform Control and Monitoring System (EPKİS) manufactured by YALTES within 90 days, and started operating in the Naval Forces in March 2020, upon the completion of its modernization. 

The first four of the DOĞAN Class Assault Ships that entered service in 1977-1981 were subjected to Half Life Modernization between 1998 and 2002 and in this context the Fire Control, Electronic Support Measures (ESM), Communication and Engine Control Systems of the Assault Ships were modernized by the Istanbul Shipyard Command with the participation of Selex Communication and MIKES companies. The agreement on the Doğan Class Integrated Communication System Half Life Modernization Project was signed as part of the project between the Naval Forces and Selex Communication (now Selex ES Türkiye) in August 1998. On the other hand, the SUSIE Electronic Support System of the Assault Ship was replaced with MIKES’ ELDES-21 Electronic Support System. The SUSIE EST System of the RÜZGAR Class Assault Ships started to be modernized with Aselsan’s ARES-2N Electronic Support System since 2010. The DOĞAN Class Assault Ship ESW System Modernization Project was launched upon the contract signed with Aselsan, and the replacement of the ELDES-21 ESW Systems of the ships with the ARES-2Ns started in 2019. However, the replacement of these ships with new generation Turkish Type Assault Ships is critical due to the frequent engine problems arising in the 43-year-old DOĞAN Class Assault Ships and the main propulsion system has difficulties at high speeds. 4 diesel engines of the MTU 16V956TB91 series with a total capacity of 12,000hp are being used in DOĞAN Class Assault Ships. The W6 maintenance/overhaul of the MTU diesel engines of the 16V956TB91 series that needs to be conducted after 6 years of utilization or every 6,000 hours, can be executed at MoND Istanbul Shipyard. 

Turkish Type FAC Project from Past to Present 

Within the scope of the Turkish Type Fast Attack Craft Project launched by the Presidency of Defense Industries (SSB) in 2013 for the domestic supply of 10 indigenously designed, new generation high speed assault ships for 4+6 (option) to replace 4 DOĞAN, 4 RÜZGAR and 2 YILDIZ Class Assault Ships in the inventory of the Turkish Naval Forces, the Request for Information (RFI) was published on July 25, 2013. This RFI was then revised and published again on September 10, 2013. The SSB finalized the RFI Final Report that was prepared considering the responses that were submitted by the relevant companies and sent it to the Naval Forces Command on December 26, 2014. 

The RFI acknowledged that the companies taking part in the Defense Industry Sectoral Strategy Document Naval Platforms Sector Strategy of 2009-2016 and the companies/ institutions/ organizations that are entitled to obtain the RFP by responding to the RFI on the New SAT Boat Supply Project for the Special Boat Squadron Operation, that acquired Facility Security Clearance, has or have applied for the Production Permit and that having the core business of ship building and the foreign shipyards that are deemed by the SSB to advance the Project in terms of technology, product and infrastructure, that already built similar platforms in terms of capabilities and that will be invited in this context are able to obtain the document. 

The document underlined that STM and foreign companies/ institutions/ organizations that were deemed to advance the Project in terms of technology, products and infrastructure by the SSB and were invited to this end, were applicable to submit proposals for the Main Drive and Propulsion System of the RFI, and that Aselsan, Havelsan and MilSoft could respond to RFI’s on the Combat System. Regarding the RFIs on the Weapon System section, Roketsan and Aselsan and the foreign companies/ institutions/ organizations that were deemed to advance the Project in terms of technology, products and infrastructure by the SSB and had been invited in this context, could submit proposals. 

The deadline identified initially as 23 September 2013 to receive the RFI over the revised version was first extended to 11 October 2013, the date for submitting the proposals on the other hand was extended to 22 October 2013 from 30 September 2013. Responding to the RFI, ADIK, ARES, DEARSAN (initially offered its original design with a single hull 65m long and 45knot speed, and then Norwegian's Skjold Class design as a High-Speed FAC with a speed of 60+ knots), Istanbul Shipyard, RMK Marine and Yonca-Onuk Shipyards seized the opportunity to introduce their indigenous solutions over the scaled models they exhibited to visitors throughout IDEF ‘15. The financial size of the Project was estimated at US$ 600 Million by the SSB at that time and it was being executed by the SSB’s Patrol Ships Projects Group. 

After lengthy suspensions due to financial bottlenecks, the project was placed back on the agenda in 2018 and a series of amendments were made on the specifications. In this scope, for instance the specification on the speed identified previously as 60 knots was revised as 45 knots. The negotiations with STM were launched in 2019 and on October 14, in his speech at the 9th Naval Systems Seminar held on 14-15 October 2019 in Ankara, Naval Platforms Department Head at the Presidency of Defense Industries, Alper KÖSE confirmed this by saying, “We are working on the Turkish Type Fast Attack Craft Project with STM…” Although the agreement was signed at the end of August 2020, neither the SSB nor STM made any official statements until December 29. However, we were informed that the contract was signed in the first half of September 2020, by an official of the company performing activities in the sector. 

FAC-55 Turkish Type FAC Design & COGAG Main Propulsion System 

When we look through the indigenous solutions developed as part of the Turkish Type Fast Attack Craft Project, we observe the domination of air-cushion catamaran type designs to address the requirements such as mono-hull or high speed. The proposed solutions contained steel sheets for the boat and aluminum sheets for the superstructure. Aluminum sheets are preferred as they offer less, and easier maintenance compared to the steel sheets (shipbuilding steel). Despite its risk of burning and vulnerability to getting damaged compared to the steel sheets, aluminum sheets, thanks to their lightness, enable a remarkable reduction in the displacement of the platforms and therefore allow the utilization of smaller engines in the ships. 

The high-speed requirement of the Project led STM to initially conduct activities to develop a boat form that will achieve the demanded speed level. In this context, the Surface Effect Ship design was also considered. This application, where the air cushion is placed between the two hulls, enables the ship to achieve high speed by minimizing contact between the surface and the ship. Then again, STM did not opt for the SES configuration due to the limited buoyancy caused by the air cushions which led the ship to carry a less useful load and frequent replacement of the air cushions due to friction and as the sliding boat was considered the most appropriate one for maintaining the speed in various sea conditions, STM selected that model. 

STM opted for steel as the construction material of the hull and upper deck (anti-magnetic steel was selected in the new design.) Steel’s resistance when the boat hits underwater rocks and its flexibility were influential in its selection as the construction material in the boat’s structure. For the FAC-55 design, STM preferred the COGAG configuration in which gas turbines can operate simultaneously in the main drive configuration. In the pool tests, it has been shown that the FAC-55 can reach a speed of 60 knots with the hull form COGAG drive system and it can reach 55 knots in Sea State 3.

FACs are defined as boats shorter than 70m with a speed over 30 nautical miles per hour and displacements lower than 700 tons. When we examine boats worldwide, we come across the following facts: 

Diesel engines are utilized in boats with displacements less than 240 tons and speeds less than 45 nautical miles an hour,

Even though boats with displacements between 240 to 700 tons and speeds varying between 30 to 45 nautical miles per hour mainly feature diesel engines, compound propulsion systems composed of gas turbines are also being used in models such as the Hayabusa Class model that serves Japanese Naval Forces.

Gas turbines are only preferred for boats with speeds over 45 nautical miles per hour. 

It is claimed that the sole utilization of gas turbines in the main propulsion system provides a weight advantage, even when the fuel is included, that propulsion system with gas turbines covers less space and it is said to be lighter. Even though the main propulsion system with gas turbines offers ships advantages such as reaching higher levels of speed and more rapidly compared to the diesel engine/gas turbine configuration, it also features disadvantages such as higher fuel consumption and therefore a higher thermal footprint due to less patrol time in the operational area. For instance, while the detection range of an assault ship with diesel engines by a thermal camera under favorable weather conditions is around 4nm, the detection range of a ship with gas turbines will be much higher. This can yield to early detection, which might have a disadvantage in engagement, together with the possibility of being more vulnerable against IR guided anti-ship missiles. Without a doubt, the measures required to minimize these disadvantages in the design have been adopted as the FAC-55 will have a displacement of 535 tons. For example, where the KILIÇ Class that weighs 552 tons at full load features 60-65 tons of fuel, the FAC-55 design with 535 tons of displacement is designed to have the capacity of carrying 90 tons of fuel. Necessary arrangements to maintain a lower radar cross section (RCS), reduced infrared signature and reduced acoustic and magnetic track were made in the hull and upper deck design of the ship. Moreover, in addition to Chaff/Flare Launchers, ARES-2N ESM and AREAS 2NC EW are expected to be used against IR/RF guided missile threats.

The full length of the FAC-55 design is indicated as 62.67m, its maximum width as 9.84m and its draft is stated as 1.68m. Considering that the draft of the existing FACs in the inventory of the Naval Forces is around 3m, it is thought that they can manage in more unpredictable and shallow terrain in the Sea around Islands. The FAC-55 will have gas turbine engines with 28MW power and 3 water jets, its maximum speed will be 55+ knots and economic speed will be 18 knots. The ship will have a comfortable accommodation for 34 personnel, and it is planned to have a cruising range of 1,000nm at a speed of 20 knots and 750nm at a speed of 50 knots. The duration of the ship at sea is 7 days. In addition to underwater systems such as sonar and light torpedoes, the low silhouette FAC-55 is designed to carry the same systems and weapons as a corvette. The superstructure of the ship is shaped to enable low radar cross section marks and in addition to eight RGM-84L Harpoon Block II Surface to Surface Guided Missiles, the boat is armed with a 76/62 Super Rapid Naval Gun with stealth shield, two 12.7mm STAMPs, one Mk49 Mod 3 RAM Launcher with 21 cells, two Chaff/Flare Decoy Launchers Systems, an IFF system, E/O Director, STING Fire Control Radar, SMART-S Mk2 3D Search Radar, ARPA/LPI Navigation Radar and HF/VHF/UHF Communication Systems. 

In line with the Term-I Agreement Design Contract in the Turkish Type Fast Attack Craft Project, I expect STM engineers will make a series of modifications in the existing weapons and sensors configuration of the FAC-55 design to meet the TNFC’s changing requirements. In this context at least two alternative designs would be prepared each containing different weapons and sensors (one with some outsourced ITAR-Free equipment and indigenous weapon and sensor systems the other would contain both indigenous and foreign-origin weapon and sensor systems) layout pursuant to the CAATSA sanctions imposed in mid-December 2020 as well as the embargoes placed for several years. The modified FAC-55 design with indigenous weapon and sensor systems shall feature an X-Bant Multifunctional AESA Radar (scaled version of Aselsan ÇAFRAD CFR or HAZARD 3D) with a fixed or rotating antenna, ALPER LPI Navigation Radar, X-Band or Ku-Band SatCom Terminal, PIRI or PIRI-ES Infrared Search and Tracking (IRST) System, ARES-2N Radar ESM and AREAS 2NC Radar Electronic Attack Systems, ATMACA or OMGS Anti-Ship Guided Missiles with KEMENT Data Link System, AKR-D Block I (AKREP) Fire Control Radar, Laser Warning Receiver Systems (LWRS) and ADVENT Combat Management System (CMS). In case the 21-cell Mk49 Mod 3 RAM Launcher and RIM-116 Block IA/HAS or Block II Missiles could not be procured due to the CAATSA sanctions or the ongoing exports license embargo being imposed at least for the last three years, an alteration on the design can be proposed to enable the integration of either the 35mm GÖKDENİZ CIWS or the SUNGUR PMADS or SAPAN/ HİSARA+ air defense missile systems