The underwater domain is witnessing a significant transformation as naval powers worldwide invest in advanced lightweight torpedo systems to counter emerging threats. As could be observed during the UDT 2025 conference and exhibition, lightweight torpedoes are no longer merely complementary weapons but increasingly central to modern surface and anti-submarine warfare strategies. Interestingly, modern lightweight torpedoes are increasingly being designed with multi-mission capabilities, including engagement of surface targets.

The MU90 IMPACT, developed by EuroTorp, exemplifies this trend with its sophisticated multi-frequency acoustic seeker that enables it to classify all types of smart decoys and jammers within seconds. Its shaped charge warhead is specifically designed to penetrate double submarine hulls, but its advanced guidance systems also make it effective against surface targets when necessary. EuroTorp's MU90 IMPACT continues to demonstrate its battlefield validity with over 1,000 units produced and equipped on 150 platforms across navies including France, Italy, Germany, and Australia, among others. An EuroTorp representative told FW MAG that “the MU-90 remains effective and valid on the battlefield, as confirmed by the growing community of users. Requirements are changing, however. We observe that navies are increasingly searching for diversifying launching solutions, including surface, air, and sub-surface assets of all kinds, manned and unmanned.” As far as production capacity is concerned, EuroTorp confirms that as many as 100 torpedoes per year can be manufactured, and this figure could easily be doubled in a very short delay.

This tendency seems confirmed also by Saab, with its TORPEDO 47, and Roketsan, with its ORKA (first picture). Sweden's 400mm diameter weapon uses a rechargeable lithium iron phosphate battery and a pumpjet propulsor. Already operational since 2023, the Swedish Defence Materiel Administration is considering further improvements, including wideband acoustic homing, improved wake-homing performance, and fibre-optic guidance to replace copper wire. The system has a small footprint with unique capabilities that creates opportunities for new operational scenarios, specifically allowing torpedoes to be deployed from smaller and possibly unmanned surface vessels. Indeed, a stand-alone configuration is possible. In this case, the system can operate independently and be supervised by a console on-board a vessel via a wireless link.

The TORPEDO 47 has been demonstrated in cooperation with the Swedish Navy and has also been demonstrated for the US Foreign Comparative Testing (FCT) program. During UDT 2025, Saab presented a simulation outlining multiple launching options for the lightweight torpedo, stressing especially the possibility of using USVs as launching platforms, thus making it possible to create complex ASuW and ASW arenas featuring diverse assets. Once launched, active or passive homing can be selected, and the fuse is optimized for both surface vessels and submarines.

In the simulation, two torpedoes were launched to demonstrate some possible tactics.  The first one uses its sensors for reconnaissance and assessment among multiple potential targets (or false signal) – especially in shallow waters, populated by multiple underwater objects and subject to strong clutter. In addition, the first torpedo may induce the target to lying on the seabed or to activate evasive manoeuvres. In both cases, this favours the second torpedo, which is tasked with the destruction of the target through its omnidirectional warhead - that can switch between impact fuse and proximity fuse.

Turkey's Roketsan is making significant progress with its ORKA lightweight torpedo program, leveraging experience gained from developing the AKYA heavyweight torpedo. ORKA is a fully indigenous, next-generation lightweight torpedo developed by Roketsan for the Turkish Navy. This 275mm diameter torpedo weighs 220kg, measures 2.85m in length, and can be launched from surface ships, helicopters, maritime patrol aircraft, and unmanned aerial vehicles to engage submarines. Powered by a brushless DC electric motor with lithium batteries and pump-jet propulsion, ORKA achieves speeds exceeding 45 knots with an operational range of 15km (up to 50km when air launched). It features active/passive sonar homing capabilities with acoustic countermeasure resistance and carries an insensitive high explosive shaped charge warhead. Hakan Kabalar, Unit Head, Central Asia and Far East Region of Rocketsan, explained that “choosing this size and weight reponds, of course, to the Turkish Navy’s requirements. But it also brings some advantages. This torpedo is optimised for launch from helicopters and UAVs, but its compact design allows for launch from other platforms. For new uses, doctrines are sometimes not mature, but the ORKA is flexible enough to fit most of possible future scenarios.” Kabalar also clarified that the weight is of paramount importance when CONOPS might include the launch from a variety of platforms not available previously, thus influencing also choices on warhead, sensors, and other components. His comments confirmed once again what highlighted by Saab and EuroTorp representatives, with the growing popularity of torpedoes as flexible weapons, easy to produce, and deployable from multiple assets.

Lastly, one conference was dedicated to the ongoing upgrade of BAE Systems’ STING RAY torpedo, which has evolved significantly from its Mod 1 to the upcoming Mod 2 variant. The STING RAY Mod 1, in service since 2001, was developed from the original Mod 0 torpedo that entered service in 1983. This lightweight anti-submarine warfare torpedo is currently used by the Royal Navy, Royal Air Force, and Norwegian Armed Forces, among others. The STING RAY torpedo is a lightweight anti-submarine weapon with a diameter of 330 mm and length of 2.6 meters. Weighing 267 kg at launch, it carries a 45 kg TORPEX shaped charge warhead. Powered by a magnesium/silver-chloride seawater battery driving a pump-jet propulsion system, it achieves speeds of 45 knots with an operational range of 8-11 km. The torpedo features sophisticated active/passive sonar homing capabilities with autonomous target detection, classification, and attack functions. It can be launched from surface vessels, helicopters, and maritime patrol aircraft against all types of submarine targets.

The Mod 1 variant features a sophisticated acoustic homing system, a highly accurate navigation system, and autonomous target detection, classification, and attack capabilities. It was specifically designed to counter both fast, deep-diving double-hulled submarines in oceanic environments and quiet conventional submarines in coastal waters. Key improvements in Mod 1 over its predecessor included a completely new sonar system, an insensitive munition warhead, new tactical and navigation systems, and a sea water battery system. In June 2024, the UK Ministry of Defence awarded BAE Systems a £60.1 million contract for the assessment phase of the STING RAY Mid Life Upgrade (SRMLU) to develop the Mod 2 variant. This four-year assessment phase covers the design and development of the Mod 2 upgrade, production of prototype weapons, and in-water trials.

In September 2024, BAE and Malloy Aeronautics successfully demonstrated this capability by dropping an inert STING RAY Mod 2 torpedo from a T-600 drone during NATO exercise REPMUS in Portugal. BAE Systems' presentation at the UDT conference showcased significant advancements across three key domains of torpedo technology. The hardware advancements introduce new sensors that enhance monitoring capabilities, providing more comprehensive data collection and analysis. These improvements are built upon a Secure-by-Design philosophy, embedding cybersecurity directly into the hardware architecture rather than treating it as an afterthought. The hardware innovations also include an improved recovery system for trials, ensuring valuable prototypes can be retrieved efficiently after testing. Perhaps most notably, BAE Systems has embraced additive manufacturing techniques for rapid prototyping, allowing for faster iteration and development cycles while potentially reducing costs and material waste.

The software advancements demonstrate a sophisticated approach to torpedo system development with a spiral update methodology for on-board software, enabling continuous improvement while maintaining operational stability. Engineers have successfully integrated modelling and software components with enhanced visual clarity, improving both development efficiency and user experience. The high-fidelity simulation environment provides realistic testing conditions, while the groundbreaking "Through the skin" reprogramming capability eliminates the need for disassembly when updating software - a significant advancement for field maintenance and upgrades.

Complementing these developments, the simulation advancements include both Offline Simulator (OLS) and Real-time Simulator (RTS) systems that provide critical insights into torpedo effectiveness across various scenarios. These simulation tools enable thorough testing of software updates in diverse operational environments before deployment. Additionally, the RTS capability delivers real-time training for operators, enhancing preparedness and proficiency without requiring actual torpedo launches, thereby reducing costs and increasing training opportunities. As highlighted by BAE Systems’ engineers, the focus on software and simulation will allow the torpedo to adapt to emerging and unforeseen threats over time thanks to prompt, plug-and-play updated any time a new technology attemps to erode the torpedo's efficacy on the battlefield.

To sum up, as naval warfare continues to evolve, lightweight torpedoes are becoming increasingly sophisticated, versatile, and lethal. Their integration with unmanned systems, improved guidance technologies, and enhanced warheads ensures they will remain critical components of naval arsenals for decades to come. The ongoing development programs across multiple nations highlight the strategic importance of these weapons in maintaining underwater dominance in an increasingly contested maritime environment.

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