“We Would be Glad to Cooperate with Türkiye in the MILDEN Program as We Have Done in Surface Ships!”
Defence Turkey: Can you elaborate on the current status of Air Independent Propulsion (AIP) powered S-80 (Isaac Peral Class) Submarine Program, covering the construction of 4 state-of-the-art submarines for the Spanish Navy?
Germán Romero VALIENTE: The first submarine of the S-80 Class has performed a successful sea trials period. The first of her class “S-81 Isaac Peral” was commissioned and delivered to the Spanish Navy on November 30, 2023 after a successful sea trials period.
The construction of the following three submarines for the Spanish Ministry of Defense is progressing well in Cartagena Shipyard (Submarine Business). The second submarine (S-82) is currently in the construction and integration phase. According to the schedule, the pressure hull of the submarine will be completely joined during the first semester of 2024 prior the commencement of the testing phase. The third submarine (S-83) will be enhanced with the BEST AIP System (Bio-Ethanol Stealth Technology Air Independent Propulsion System). The AIP System successfully passed the Factory Acceptance Test (FAT) in 2023. So, a proven solution is now available and ready to embark in the section 3 of the S-83 Submarine (summer of 2024). The fourth submarine (S-84) is under construction of various sections of the pressure hull which will be finished by the end of the year.
Defence Turkey: What can you tell us about the feed backs you have received during the sea trials conducted with the S-81 Isaac Peral Submarine and since the induction of the S-81 into the Spanish Navy Submarine Flotilla?
Germán Romero VALIENTE: The S-81 crew has especially stood out the run of the submerged test sequence for validating the Safety Operative Envelope (SOE) until Deep Diving Depth (DDD) and maximum speed, as well as the coordination with the Shipyard during sea trials. Regarding the platform, they have highlighted the excellent depth control of the submarine through the Steering & Diving Control System (SDCS) and the great performance of the Integrated Platform Management System (IPMS).
Defence Turkey: The S-81 was originally due to be delivered in 2015 but due to a long process to extend the submarine’s hull so to correct its original design (to restore its buoyancy) and COVID 19 pandemic the delivery could only take place in November 2023. Due to this delay in the delivery schedule, is there any plan to upgrade the equipment of the submarines after delivery?
Germán Romero VALIENTE: The industrial, technological, and scientific content that today surrounds the S-80 Program is much greater than it would have been if everything had occurred according to the initial plan. New and digital technologies have been an exceptional protagonist during the last phase of their development, for instance, a cybersecurity system has been implemented on-board to protect the critical systems from possible digital threats. Its quick evolution has forced the Shipyard to consider the control of obsolescence as a critical issue, promoting its incorporation into the design and manufacturing processes.
As every Defense program with a long-life cycle, the S-80 Program has established an Obsolescence Management Plan for life cycle support. The goal is planning the replace of certain components or equipment that may become obsolete in the short, medium or long term. The Shipyard collects information from the different suppliers to identify these components allowing us to advance the purchase of some spare parts and even begin to plan modernizations and/or technological upgrades. Inside the new S-80 In-Service Support Technical Office (OTACV) there is an specific section in charge of the modernizations and upgrades.
Defence Turkey: According to Navantia brochure the S-80 Submarine is fitted for UGM-109 Tomahawk Cruise Missile for the strategic strike capability. Do you have any plan to perform firing tests with Tomahawk Missile in coming period?
Germán Romero VALIENTE: Navantia has performed the roadmap to achieve the capability for launching missiles for the S-80 Program, so the submarine’s weapon system is fitted for Tactical Land Attack Missile (TLAM) like Tomahawk and there is margin for the weapon control units; next steps would require Spanish Government's final decision.
Defence Turkey: Navantia has a long tradition in designing, building and operating warships including submarines. As a follow up to the S-80 Program, have you defined a roadmap including several innovation projects in order to evaluate the integration of certain technologies (such as Lithium-ion batteries and Vertical Launching System) and systems that could be part of future S-80 upgrades, evolutions for other customers or additional units in the class? If yes, what can you tell us about your roadmap?
Germán Romero VALIENTE: Navantia is working on the introduction of additional capabilities for the S-80 Submarine evolutions as deployment and collection of UUV, alternative hydroplanes configurations or lithium-ion batteries. Regarding this topic, lithium-ion batteries are now of interest for most navies. This technology allows the submarines, considering the same volume as for lead-acid solution, to increase their time at maximum submerged speed and reduce the indiscretion rate with less weight. Navantia is working together with potential suppliers to develop and integrate the latest available technology in the S-80 design at the earliest opportunity, either for export opportunities like P-75(I) in India or for the Spanish Navy should this be required. The Spanish Navy is closely following this project.
Defence Turkey: Concerning both national and international markets, do you have a plan to start the exploration of the design features for the future submarines, say S-90? In the air next generation fighter jets will feature the flexibility to undertake manned and unmanned missions. Do you thing in coming decade new generation/future submarines will also gain such capability? What can you tell us about Navantia’s approach to autonomous underwater vehicles?
Germán Romero VALIENTE: Navantia is now focused on the additional or alternative features that could be fitted into the so-called S-80 evolved designs, either for export market or additional units for the Spanish Navy should they be required. For future S-90, additional technological programs would be expected but the conversations are still at a very preliminary stage. In relation to unmanned platforms, some countries had this internal discussion about whether buying manned or unmanned submarines. The answer today is that we are not ready to have a fleet of unmanned vehicles only and this will take years. And even when all the technical challenges are solved, there are many discussions about ethic related topics that need to be addressed and assumed in most of the countries worldwide.
What is clear is that submarines are becoming more and more mother ships, that will need to deploy all type of vehicles and would have to perform their missions in combination with them and with the same level of integration they have already achieved with other aero and naval manned systems.
For the last decade Navantia has been working in different solutions (including a patent of a self-compensated shelter) for deployment of these vehicles and special forces, different trade-offs were made and solutions that were not chosen for the S-80 of the Spanish Navy, are available for other potential customers.
We also see possibilities in providing this market region with extra-large Unmanned Underwater Vehicles (XL UUV) and dwarf attack submarines in the range of 300-400 tons, midget or small attack submarines. Navantia is currently exploring these types of solutions.
Defence Turkey: The S-80 Program represents the greatest industrial and technological challenge ever faced by Spain’s defense industry. Can you elaborate on the huge investment performed at the Cartagena Shipyard to allow Navantia to have a state-of-the-art facilities both for submarine design and construction and dedicated to create an adequate physical (especially focusing on the pressure hull manufacturing) and digital infrastructure?
Germán Romero VALIENTE: The differences between S-70 and S-80, both in technologies and performances, are so important that a revolution more than an evolution has been required. For this purpose, huge investments have been performed in this shipyard during the last 20 years, allowing Navantia to have state of the art facilities both for submarine design and construction. These investments have been dedicated to creating the adequate physical and digital infrastructure, the main systems of the product and the shipyard processes. Now, these facilities are also ready to perform the planned tasks for In Service Support.
In relation to the physical infrastructure the investments have been focused on those activities that are considered “core” for submarine construction. Among them I would like to highlight those related with pressure hull manufacturing. New workshops have been built for the fabrication of frames and sections. The Sections Workshop is the place where hoops and sections are built, it has a bending machine for the pressure hull shell and welding automated systems for different parts with minimum human intervention. An additional investment is also in process and will allow the automation of the inspection thanks to the use of advanced ultrasonics that will remove the current requirement for radiographs.
The workshop where the frames are manufactured includes robots to automate fabrication of its parts, the web and the flange, and also devices for automated welding between them. It is important to say that there is a dedicated room where welding parameters are monitored to check for any deviations that may occur and act immediately on those. Apart from all that, here the investments continue in full alignment with Navantia’s digital transformation strategy.
Defence Turkey: Can you elaborate on the place/importance of submarine design and construction within the scope of the Navantia’s digital transformation strategy? What can you tell us about Navantia’s digital infrastructure (including digital mock-up/digital twin and simulation tools) that being utilized within the scope of the S-80 Program?
Germán Romero VALIENTE: From physical to digital infrastructure, in relation to that, it has been necessary the integration of all different tools, CAD, CAE, PLM and ERP, that are required to provide support to the needed product and management processes. Specifically, a complete digital mock-up has been created which integrates the result of the design and all the attributes of their components. Moreover, this virtual design center has been created and has become the place where all the design reviews and quality gates meetings take place. Here all participants can visualize the current design and navigate through the different areas of the submarine having at the same time all the details of the actual product design.
Simulation tools also play an important role in this digital infrastructure, verification and validation projects were developed to assess the adequacy of both commercial and customized tools. So, Navantia’s digital infrastructure, including digital mock-up and simulation tools, is a cornerstone of innovation within the S-80 Submarine Program.
Moreover, Navantia has made history with the F-110 Frigate Program, featuring the world's first contracted digital twin for a warship. This groundbreaking approach is not unique to the F-110, as other programs such as BAM-IS have also adopted digital twins as part of their development.
The inherent characteristics of a digital twin facilitate a high degree of component reuse at the lower development layers and at the information generation processes, since they stem from the same engineering tools. Therefore, there is no doubt that submarines stand to benefit from the progress made in these areas, paving the way for the integration of digital twins in future submarine projects.
Defence Turkey: With a length of 80.8 meters, a diameter of 7.3 meters and a displacement of almost 3,000 tons, the S-80 Class Submarine design has unique capabilities among NATO non-nuclear submarines. How the S-80 design is different from other conventional submarines in the market, such as A-26, Type 212 NFS, Super Dolphin II and KSS-III?
Germán Romero VALIENTE: Far from comparing ourselves with the different competitors, it is fair to say that the S-80 Submarine is a unique conventional submarine with performances only available in current nuclear-powered attack submarines (SSN). She is a long-range oceanic diesel-electric submarine enhanced with the BEST® AIP System. This AIP is an existing solution offering the better performances and allowing the submarine to remain in depth for very long periods. This third generation AIP has been developed for expeditionary submarines and stands out because replace hydrogen storage by hydrogen production onboard. The submarine is able to perform any of the missions required for a submarine force, highlighting the integrated combat system and the weapon system that may cope with most of the modern weapons in different launching modes.
Besides, this is the first NATO SSK that is fitted with SLCM capability apart from the anti-ship and shore targets missiles that are present in other submarines. The ICSC (Integrated Nucleus of the S-80 Combat System) also integrates a sonar suite developed by Lockheed Martin and SAES (towed array sonar and his deployment system), all of them with a higher number of hydrophones and better performances compared to most of conventional submarines.
The submarine also has a very high-level of automation allowing for a very reduced crew and specifically incorporates a fly-by-wire system to steer it. The S-80 has an optimum maneuverability for an oceanic attack submarine and negligible restrictions on the Safety Operative Envelope. It has low signatures requirements and a low Indiscretion Ratio for performing the mission and return home undetected. And, in terms of maintenance, the S-80 Submarine has a maximum operational availability...
Defence Turkey: Starting from the S-83, the S-80 Submarines will be equipped with the innovative 300kW Bio-Ethanol Stealth Technology (BEST) Air Independent Propulsion (AIP) System, using bio-ethanol fuel cells and an Ethanol Reformer, that generates the required hydrogen from ethanol through a reformer. The first and second submarines that built without AIP Systems will receive them during initial major overhauls. Can you elaborate on the AIP BEST System for the S-80 Submarines? How does it operate and how is it different from other AIP Systems in the market?
Germán Romero VALIENTE: Navantia’s BEST AIP is currently the most advanced and revolutionary solution in the market to extend conventional submarines diving endurance, therefore providing very high tactical capabilities to the Spanish Navy. Achieving this goal has required two decades of rigorous technology development process, a hard and long path not exempt of technical challenge. The success in the AIP Factory Acceptance Test (FAT) last July meant hitting a key milestone on the S-80 Program, enabling the embarkment of the first unit on-board S-83 Submarine.
Whilst first generation AIPs using Stirling engines have improved over the years, they still represent a very rudimentary and low-efficient solution. Second generation AIPs include a fuel cell which combines an oxidant and fuel to generate power. However, this renders a problem with Hydrogen storage, requiring large and heavy hydride cylinders placed outside the submarine and logistic issues for the supply ultra-pure Hydrogen. Whereas first and second generations AIP Systems are still provided in small submarines without ocean going ambitions, the third generation AIPs have been developed for expeditionary submarines. These systems replace hydrogen storage by hydrogen production onboard by processing ethanol, methanol or high-purity diesel-oil as fuel. Nevertheless, nowadays methanol and diesel-oil based solutions are currently on development, not assigned to any submarine program.
Navantia’s BEST AIP combine the expertise of the Spanish company Abengoa Innovación for the fuel processor, and the American company Collins Aerospace, well known for their work in aerospace for NASA, for the fuel cell. Hydrogen is produced from bio-ethanol: organic, safe and readily available worldwide, as opposed to other solutions.
This challenge required the development of a cutting-edge Hydrogen Generator, a high thermal efficiency miniaturized bio-ethanol processor to feed a Proton Exchange Membrane (PEM) fuel cell specifically developed, as well, for the S-80 Program. Process flue gases are managed by the Carbon Dioxide Disposal System, providing perfect gas dilution in seawater, avoiding presence of bubbles which could degrade submarine stealthiest, to guarantee an exceptional noise level performance as in pure electric diving. The system is fully automated, not requiring additional crew or any high qualification personnel for its operation.
The fuel cell supplied by Collins Aerospace is specifically developed to military naval specifications, not a commercial based PEM Fuel Cell adapted for submarine use. The cell stacks are made of porous bipolar plates for passive water management and uniform, continuous membrane humidification (no need for humidification or liquid water removal systems). This advanced design not only makes the fuel cell simpler at the system level, but also provides a high service life duration operating on reformate gas and pure Oxygen (not air). This avoids the need for Hydrogen purification systems, such as membranes, or simulate air, a further simplification of the system.
Defence Turkey: What can you tell us about the Center of Excellence established for the either individual and integrated tests of BEST AIP System and able to simulate environment that a S-80 Submarine would face thanks to its ability to assess any situation or incident that may occure during a real mission.
Germán Romero VALIENTE: The support of BEST AIP technology maturation has required the development unique testing capabilities in Cartagena’s Shipyard. This means over 20 Million Euros investment by Navantia to build a facility capable to provide a simulated operation environment. This Center of Excellence provides test benches able to simulate exhaustion with a turbulent jet on the skin of the submarine for the entire range of immersion levels. This has allowed the intensive testing of the equipment, individually, partially interconnected or fully integrated, and will allow in the near future to demonstrate the operation of the complete AIP section before its joining to the S-83 Submarine pressure hull.
This facility will provide support to the S-80 Class Submarines life cycle as well, as a Land-Based Test Site, with a replica of the embarked unit to assess any situation or incident that may occur during a real mission. Additionally, the Centre of Excellence will provide training services for the crew, workshops for equipment maintenance and overhaul and test benches for technology second step maintenance activities.
Defence Turkey: Representing one of the major innovations incorporated in the S-80 Class Submarines, Navantia's BEST AIP System combines the expertise of the Spanish company Abengoa Innovación for the fuel processor, and the American company Collins Aerospace, for the fuel cell. Do you expect any restriction in the export of S-80 Submarines due to the role of an American company? Does the AIP BEST System ITAR Free product? Are you offering BEST AIP System also to India and Poland?
Germán Romero VALIENTE: All technologies developed for the BEST AIP are owned by Navantia. By this we mean we have the rights to export and the knowledge to adapt to any customer requirements. Certainly, as an USA Company supply, Collins Aerospace Fuel Cell is under ITAR regulation, but we do not expect any restriction in the export of S-80 Submarines due to this fact. As an example, we had the support of our American partners when Navantia presented the offers to India and Poland, no problems found throughout the process due to this fact.
Defence Turkey: What could you tell us about the international presence of Navantia in global conventional submarine sector, and ongoing marketing efforts under the Poland’s ORKA and Indian P-75(I) Programs? Where do you see the strong points of Navantia in these programs/tenders? Can you elaborate on your proposals such as potential efforts in the indigenization of the submarine and on the technology transfer (ToT) under the ORKA and P-75(I) Programs?
Germán Romero VALIENTE: The fact that the first of class S-81 Isaac Peral is already delivered to the Spanish Navy on November 30, 2023 means a lot in relation to the global conventional submarine market, and it shows this project is a reality. Having the S-81 in Spanish Navy’s hands drives the international market to recognize Navantia as a submarine design authority and able to offer our own product.
Together with L&T, technical offer was submitted in response to RFP for project P-75(I) and Ministry of Defense has recently communicated the compliance with respect to the stipulations of this RFP, so we are in the final stage, and we do believe there are still good chances to win the contract. This final stage before opening the bids is the execution of the AIP System Field Evaluation Trials (FET). Navantia is currently exploring options to undertake the FET sooner, and we are looking at the S-82.
Regarding ORKA Program, we are participating at RFI phase with an adapted technical solution of a submarine already at sea modified to operate at Baltic Sea. Our technical solution is fitted for the launching of Tomahawk missiles which is one of the main requirements. One of Navantia’s advantages is the Spanish Navy support, for submarine programs, training offer is critical and the support of a parent Navy already operating the design can make the difference. We’re offering a ToT program for the local establishment of submarine sustainment capability, transferring to the Polish Navy the sovereignty in the availability and capabilities of their submarine fleet. Navantia’s proposal is based in the involvement of local shipyards and local suppliers enhancing local value naval chain.
Navantia has a very flexible ToT model, proven on several international programs (including submarines in India). In that sense we feel comfortable working either with public or private sector.
Defence Turkey: Having a long tradition in designing, building and operating warships including submarines Navantia is capable to deliver either the complete submarine (either built in Spain or through a transfer of technology program) or cutting-edge systems that could be fitted in those submarines. Can you elaborate on Navantia’s approach MILDEN Program? Are you ready to share your know-how/extensive experience and your knowledge and capacities acquired during the development of AIP BEST System with Türkiye?
Germán Romero VALIENTE: We have received a Turkish Delegation in our facilities in Cartagena and we have shown them what we do and could offer to the MILDEN Program. Based in our experience gained on the S-80 Submarines Program, we would be glad to cooperate with Türkiye in the MILDEN Program as we have done in surface ships.
Defence Turkey: Mr. VALIENTE thank you for sparing time for our readers and good luck
