The frigate of the Aquitaine.

  In October 2024, the French Navy Admiral Admiral Ronac FDI frigate (intervention and defensive frigate) set off from the Lorient Shipyard and began a sea trial. Unlike previous sea tests of other warships in the country, this sea test not only tested the ship's navigation and power systems, but also tested other systems and equipment, including combat systems.

  In November 2024, Norway decided to purchase at least 5 to 6 frigates. On the alternative list, the French FDI frigate is in sight, competing with the German F127 frigate, the British 26 frigate and the American constellation-class frigate.

  At present, Admiral Ronac is in the final stage of the sea trial and is expected to be put into service soon.

  Admiral Ronak is the first ship of the FDI frigate. Among the ranks of frigates from all over the world, what kind of warship is the FDI frigate? What are the characteristics and advantages? Please see the interpretation of this issue.

  The new generation of "first class" warships

  In 2013, France published the White Paper on National Defense and National Security, requiring the French Navy to undertake two major tasks of deterrence and protection, and have the ability to deploy in two combat areas. One of them is to build 15 "first-class" surface ships for the French Navy.

  Since then, the work of building and renovating related warships has been carried out one after another. In 2022, France announced that this goal was achieved. Among the 15 "first-class" surface ships, there are 2 Forban (i.e., Horizon Class), 8 Aquitaine (2 air defense, 6 anti-submarine) and 5 Lafayette Class. Different types correspond to different tonnage and military designs, performing different functions.

  Among them, the five Lafayette-class ships were not newly built, but were put into service as early as 1994 to 2001, with a full load displacement of 3,600 tons, which is equivalent to an ocean-going patrol ship. Despite the "first-class" transformation, the firepower of the Lafayette-class ship is still relatively weak, and it is only equipped with 1 100mm naval gun, 2 20mm machine guns, 2 sets of 4-unit "Flying Fish" anti-ship missiles and 1 set of 8-unit "Sea Rattlesnake" missiles, and only has surface combat capabilities. Air defense capabilities can only meet basic self-defense, and lack anti-submarine fire control, underwater detection equipment and anti-submarine weapons.

  Considering that the Lafayette-class ship has been in service for a long time and the French Navy urgently needs a frigate that can not only strengthen the operational capabilities of the aircraft carrier formation but also independently demonstrate its military existence, the DCNS Group, the predecessor of the French Navy Group, proposed a new generation of "medium-sized universal frigate" design plan, which was recognized by the French military in 2015. In April 2017, the French Armistice Administration signed a contract with DCNS Group and Thales Group to build five "medium-sized universal frigates". Among them, DCNS Group Lorient Shipyard is responsible for building the platform, and Thales Group is responsible for providing "sea fire" radar, CAPTAS-4 towed array sonar, communication equipment and electronic warfare systems.

  In early 2019, the French Navy carried out ship types reforms and renamed the "medium-sized universal frigate" to the FDI frigate, namely the "intervention and defense frigate".

  In October of the same year, the first FDI frigate, Admiral Ronac, started construction. The French Minister of Defense, the French Navy Chief of Staff, and the Greek Navy General Staff at that time attended the ceremony.

  The reason why the attendees are quite high is that the FDI frigate is not only listed as the "first-class" surface ship of the French Navy, but also listed as a key export of military equipment by France, and Greece is the first customer.

  Greece ordered three FDI frigates and reserved the option to add one. The FDI frigates purchased by Greece were named Kimon Class and are currently under construction. After Greece, Norway may also become a customer for purchasing FDI frigates. In November 2024, Norway decided to purchase at least 5 to 6 frigates, with French FDI frigates, German F127 frigates, British 26 frigates, and American constellation-class frigates all on the alternative list. Moreover, the advantages of the FDI frigate are obvious because it is the only frigate built and sea trials among the options.

  Looking back at its R&D process, the progress of the FDI frigate project is basically normal. At the end of 2021, Admiral Ronac laid a keel, and the ship was launched in November of the following year. Construction of the No. 2 and No. 3 will start in July 2023 and October 2024 respectively.

  According to France's plan, Admiral Ronac should be listed by the end of 2023, and the actual enrollment time may be postponed by about one and a half years. Because it is a new ship project, from a global perspective, it is also a "conventional operation" to postpone the first ship's entry into the market by more than one year.

  It should be pointed out that the French Navy has its own unique ship classification system. Although FDI is a frigate, its hull number does not start with "F (the first letter of the frigate in English name Frigate)", but starts with "D (the first letter of the destroyer in English name Destroyer)". Admiral Ronak's hull number is D660. In fact, the situation of the Aquitaine class in the French Navy is exactly the same. Although it is called a frigate, its hull numbers are all led by "D", which means that its actual status and function are equivalent to that of a destroyer.

  "Retro" and "Modern" have a combination of

  The FDI frigates were named after French naval generals in the 20th century. Admiral Ronac was in memory of Pierre Alexis Ronac, a French naval commander during World War I and served as chief of staff of the French naval forces from 1919 to 1920. This naming method has the meaning of "reflecting on the present and chasing the past".

  However, what better reflects the fusion of elements in the past and the past is its inclined wave-breaking bow, which looks like the ironclad bow from the late 19th century to World War I. Compared with the forward-tilted bow commonly used by modern warships, this design is more "alternative", but not unique. The U.S. Zumwalter-class frigates and the German F127 frigates also use an inverted bow.

  Modern warships have many benefits to adopting inward-tilted bow design. First, it is conducive to stealth and can significantly reduce radar wave reflection in the bow area; second, it can reduce wave resistance and increase speed. However, this design also has shortcomings, such as squeezing part of the bow space, which can also lead to serious waves. During the sea trial of Admiral Ronak, in order to reduce the upward waves, a circle of wave pressing boards was installed on the bow of the ship, but the effect was not obvious. Therefore, there is a more supportive view - the design of the FDI frigate is mainly for use in the Mediterranean, and its hull structure and anti-swing technology can cope with situations such as the waves, and can also take into account the needs of operating in various sea areas such as the Atlantic Ocean.

  Although the bow is quite "retro", the FDI frigate has a "modern" feel in other aspects. For example, it has a high-tech integrated mast, with antennas of multiple systems such as ship-based navigation, phased array radar, photoelectric detection, enemy-to-foe identification, electronic confrontation, etc., which are all integrated into this integrated mast above the bridge, which not only makes the hull of this class of frigate quite neat, but also improves the ship's stealth ability.

  FDI frigates adopt a lot of cutting-edge technologies to truly realize digital design and construction. The digital architecture adopted can not only be used to process massive data, but also help frigates to undergo replacement and upgrades in the future.

  The FDI frigate has two data centers, which can achieve most of the data interoperability and backup each other. The application of dual data centers has effectively reduced the pressure brought by the increase in the number of ship-based system access points, and has also made the FDI frigate a "innate" frigate with the ability to resist cyber threats. The new network management system adopted by the FDI frigate can help non-professional crew members use an intuitive human-machine interface to monitor the platform's network operation status and intervene when discovering cyber attack behavior.

  The "modern" of this class of frigates is also reflected in the use of augmented reality technology to assist in construction and use. Workers at the Lorient shipyard used holographic lenses to install some of the FDI frigates' equipment to improve assembly efficiency. The French Navy Group also cooperated with Dassault Systems to create 3D models inside and outside the FDI frigate, which can be used for crew training and ship maintenance.

  The main ship of the maritime formation that is highly anticipated

  Judging from the "big size", Admiral Ronac is not big, 121.6 meters long, 17.7 meters wide, and has a full load displacement of 4,460 tons. Like the Lafayette class, it uses full-chitel power and has a maximum speed of 27 knots. When operating at economical speed, the endurance is about 8,000 kilometers and the self-sustaining force is 45 days.

  Obviously, looking at the new generation of frigates from all over the world that are now catching up with destroyers, such as the American constellation class with a full load displacement of 7,500 tons, the 8,000 tons British Type 26, and the 10,000 tons German F127, which are on the Norwegian procurement shortlist, the size of the FDI frigate is really far from each other. Even compared with the French active Forban and Aquitaine class, the FDI frigate is "unusual" in tonnage.

  Therefore, some people believe that the "little" FDI frigates focus on dealing with the "low-intensity confrontation" combat scenario. However, this view is very different from the positioning of the French Navy. In fact, the French Navy has high hopes for FDI frigates. Since its design, FDI frigates have been positioned as multi-purpose long-sea surface warships, able to join the French naval aircraft carrier formation or operate independently, and perform various tasks such as anti-ship, anti-submarine, air defense, and special combat force delivery.

  This is reflected in the weapons and equipment it carries.

  In terms of anti-ship weapons, the French FDI frigate has installed an Otto Melera 76mm naval gun on the bow, and two 4-mounted "Flying Fish" anti-ship missile launchers are installed in the middle of the hull. The maximum range of the new "Flying Fish" anti-ship missile can reach 200 kilometers.

  In terms of anti-submarine weapons, the FDI frigate installed a dual torpedo launcher on both sides to launch MU-90 anti-submarine torpedo. The CANTO anti-submarine bait it carries can be launched through specially designed launcher. In addition, the stern of its ship can be equipped with an NH90 "Caiman" helicopter and a VSR700 unmanned helicopter.

  In conjunction with anti-submarine, the bow of the FDI frigate is equipped with an intermediate frequency main/passive sonar, and the stern is equipped with an active/passive low-frequency towed array sonar. The former has a maximum detection distance of 25 kilometers, which can continuously track underwater targets and use the database to independently compare voiceprints. The latter is used for large-scale searches. When a suspicious target is found, the ship-based helicopter flies to the target sea area for detailed searches.

  In terms of air defense and anti-missiles, the FDI frigate has installed two sets of 8-mounted Silva A50 vertical launch systems behind the main gun of the bow, which can launch 16 "Aster-15" or "Aster-30" air defense missiles. As needed, FDI follow-up ships also plan to install or "mix" vertical launch systems to launch MCDN Naval Cruise Missiles with a range of 1,500 kilometers.

  In addition, this class of frigates has a "digital combat bridge", which can remotely control two 20mm cannons and other weapons with the help of cameras, photoelectric and fire control systems to launch strikes on small drones and small boats.

  On the perception equipment, the FDI frigate is equipped with the Thales Group's "Sea Fire" 500 S-band active phased array radar, with a maximum detection distance of 500 kilometers to the air and a maximum detection distance of 80 kilometers to the sea, and can detect 800 targets at the same time. The radar adopts a modular design and is said to complete software and hardware upgrades without returning to the factory for the full life cycle. Above the "Sea Fire" phased array radar is a dual-band scanning radar, which is mainly used to provide fire control for 76mm naval guns and "Flying Fish" anti-ship missiles. In addition, in order to deal with "low slow and small" and sea-skipping targets, the FDI frigate is also equipped with a low-altitude interception radar. It can be said that this class of frigates is "luxury" in terms of radar lineup, not only far surpassing the Lafayette class, but also surpassing the Forban class equipped with European multi-functional phased array radar and the Aquitaine class equipped with "Martial Perseid" single-sided rotating passive phased array radar.

  In terms of special combat forces, the FDI frigate can carry 28 special forces members and deploy them ashore with two rigid inflatable boats or carrier-based helicopters.

  The French military naturally enjoyed the success of such a "multi-capable" "maritime sword guard" and planned to adjust the existing French naval surface fleet structure, increase the purchase of 3 FDI frigates, and increase the number of "first-class" surface ships to 18. (Ma Xiaojing)

[Editor in charge: Wang Jinzhi]