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Torped 47

The Torped 47, designated by the Swedish Armed Forces as the successor to the Torped 45 lightweight torpedo, is a modern anti-submarine warfare (ASW) weapon system developed by Saab for deployment from submarines, surface vessels, and helicopters in shallow-water littoral environments such as the Baltic Sea.^[1] It features a fully digital homing system with active/passive acoustic detection, wire-guided control for precision targeting over several kilometers, and fire-and-forget capability, enabling engagement of both submerged submarines and surface targets in complex hydroacoustic conditions.^[2] Developed by Saab drawing on over a century of expertise in underwater systems, the Torped 47—also known internationally as the Saab Lightweight Torpedo (SLWT)—incorporates advanced technologies including a pump-jet propulsion system for reduced acoustic signature and variable speed operation (from 10 knots for search to over 40 knots for attack), powered by a high-energy lithium-based battery that exceeds the warhead's energy content.^[1] With a length of 2.85 meters, a diameter of 400 mm, and a total weight of approximately 340 kg, it offers an endurance of more than 20 km at cruising speed or over 1 minute at maximum speed, making it adaptable to modern naval scenarios involving civilian traffic and evolving threats.^[2] Initial testing of the Torped 47 began in 2020 with live firings from a corvette and submarine in the Baltic Sea, validating its performance in the region's shallow (average 55 meters depth), brackish waters with rocky seabeds and islands.^[1] The Swedish Defence Materiel Administration (FMV) placed the first production order in 2022, with deliveries beginning that year and the system entering service with the Royal Swedish Navy in 2023, followed by an additional SEK 1.3 billion contract in 2025 for torpedoes, launch tubes, spare parts, training systems, and technical support, with deliveries commencing in 2026 to equip Royal Swedish Navy submarines and surface ships.^[3]^[4] This system enhances Sweden's naval defense capabilities in the Baltic region, where it has also been adopted by the Finnish Navy (as Tp 47), by providing multi-platform launch options across submarines, surface vessels, helicopters, and other types.^[1]^[5]

Development

Background and requirements

The development of the Torped 47 stemmed from the Swedish Navy's strategic need for an advanced lightweight anti-submarine warfare (ASW) torpedo tailored to the unique environmental challenges of the Baltic Sea, including shallow waters, complex seabed topography, and variable hydroacoustic conditions that complicate target detection and engagement.^[6] This requirement was particularly acute in littoral areas like the Stockholm Archipelago, where operations demand high maneuverability, multi-target discrimination against submarines and surface vessels, and seamless integration with contemporary naval platforms such as corvettes, submarines, helicopters, and unmanned systems.^[2] The torpedo's design prioritizes silent, efficient performance in these confined spaces to counter evolving submarine threats amid heightened regional tensions.^[7] Launched in 2015 by Saab Dynamics, the project sought to replace the Torpedo 45, which entered service in the mid-1990s and faced obsolescence due to advancing adversary technologies and the retirement of key expertise within the Swedish defense sector.^[7] The initiative addressed the predecessor's constraints by focusing on extended operational effectiveness in shallow-water scenarios, where traditional torpedoes often underperform.^[1] Development involved over 100 specialists across engineering, production, and testing, ensuring the system could adapt to both cold, brackish Baltic conditions and broader blue-water applications.^[7] Central program objectives encompassed active and passive acoustic homing for versatile ASW and anti-surface target engagement, wire-guided control for precise navigation over several kilometers, and full compliance with insensitive munitions (IM) standards to enhance safety and logistical handling under international regulations.^[2] A modular digital architecture was prioritized from the outset to support ongoing upgrades, technology sharing with other underwater systems, and future-proofing against emerging threats.^[2] The effort was funded through the Swedish Defence Materiel Administration (FMV) and fostered tight collaboration between Saab and the Swedish Armed Forces, drawing on Saab's century-long expertise in underwater weaponry to deliver a system operational by 2023.^[7]

Testing and production

The development of the Torped 47 progressed through a series of qualification trials that verified its core performance parameters. Initial sea trials in 2020, conducted by Saab, the Swedish Defence Materiel Administration (FMV), and the Swedish Armed Forces, involved test firings from a Visby-class corvette and a Gotland-class submarine at sea ranges outside Karlskrona in the Baltic Sea; these trials successfully demonstrated the torpedo's homing and guidance systems, including its active/passive fully digital sonar and wire-guidance capabilities.^[2]^[8] Further qualification processes confirmed the Torped 47's operational envelope, including a range exceeding 20 km and a maximum depth greater than 300 m, enabling effective deployment in both shallow and deep waters.^[2] These verifications, combined with multi-platform integration testing, led to the torpedo's achievement of full operational capability. In late 2024, FMV and Saab conducted trials demonstrating the Torped 47's launch from a CB 90-class fast assault craft. In March 2025, additional trials from an unmanned surface vehicle (USV) were announced, highlighting its adaptability for diverse naval assets.^[9] Production and delivery milestones aligned closely with initial contracts awarded to Saab. Sweden placed its order in 2016, followed by Finland in 2018, with manufacturing occurring at Saab's facilities in Sweden.^[6] Deliveries to Sweden commenced in October 2022 to FMV, with official handover to the Swedish Navy on December 20, 2022, and entry into service in 2023.^[4]^[6] For Finland, the Torped 47 (designated TP 47) entered service on November 1, 2023, with initial deliveries supporting integration on Hamina-class missile boats and the forthcoming Pohjanmaa-class corvettes.^[10] In May 2025, Sweden awarded Saab an additional contract valued at approximately SEK 1.3 billion for more Torped 47 units and torpedo tubes, aimed at bolstering naval defense capabilities, with deliveries scheduled to begin in 2026.^[3]

Design and technology

Guidance and control systems

The Torped 47 employs a multi-mode guidance system that combines wire guidance with advanced acoustic homing to enable precise targeting of submarines and surface vessels in complex underwater environments.^[11] It utilizes a fully digital MS4 homing head capable of operating in both active and passive acoustic modes, allowing the torpedo to detect, classify, and track multiple targets through hydro-acoustic signals while discriminating against decoys and environmental noise.^[11] This homing system integrates forward-looking sonar with flexible beamforming and signal processing to enhance detection in littoral waters.^[12] For real-time control, the torpedo supports wire guidance via a thin galvanic copper wire, with provisions for optical fiber upgrades to provide a two-way data link over several kilometers, enabling operator intervention and waypoint navigation from the launch platform.^[2]^[11] This setup allows integration of external cues, such as relayed sonar data from the launching vessel, to refine targeting during the initial phase before transitioning to autonomous homing.^[12] The system also features fire-and-forget autonomy, where the torpedo can operate independently after launch using its onboard sensors for target acquisition and pursuit.^[2] At the core of these capabilities is a fully digital onboard computer architecture, which processes sensor data via high-speed Ethernet interfaces to support modes ranging from guided to fully autonomous operation.^[12] This computer enables advanced functions such as multiple-target discrimination, obstacle avoidance, and hovering during search patterns to optimize positioning in cluttered or noisy areas like the Baltic Sea.^[13]^[12] Additionally, it controls an omnidirectional warhead detonation trigger based on multi-beam sonar proximity fusing, ensuring effective engagement regardless of approach angle.^[14] Derived from Saab's extensive experience in underwater systems, the Torped 47's guidance technology incorporates modular, commercial-off-the-shelf digital electronics designed for resilience against countermeasures and superior performance in high-traffic, acoustically challenging environments.^[2]^[12] These features draw on proven Saab architectures, emphasizing adaptability to shallow-water operations and integration with battery-powered propulsion for sustained control. Ongoing development includes potential upgrades to wideband acoustic and wake-homing, along with fibre-optic guidance links.^[11]

Propulsion and power

The Torped 47 employs an electric propulsion system consisting of a direct current (DC) motor coupled with a pumpjet propulsor, enabling efficient thrust while minimizing detectable noise signatures during anti-submarine warfare operations.^[12] The pumpjet design, featuring a ducted rotor and stator configuration, significantly reduces cavitation noise compared to traditional open propellers, thereby enhancing the torpedo's stealth capabilities in littoral environments.^[2] This setup supports high maneuverability, allowing the torpedo to execute evasive maneuvers in pursuit of agile targets.^[13] Power for the Torped 47 is provided by a rechargeable lithium iron phosphate (LiFePO4) battery module, comprising 525 cells in a 5P105S configuration that delivers 4.2 kWh of energy at a nominal 346 V system voltage. Future upgrades may incorporate Lithium Nickel Manganese Cobalt Oxide (NMC) batteries for enhanced energy density.^[11]^[12] This environmentally safer battery chemistry offers extended endurance exceeding one hour at low speeds of around 10 knots, supporting a range of more than 20 km at cruising speed, while being scalable for configurations reaching 50 km or more; at maximum speeds over 40 knots, endurance exceeds 1 minute.^[2] The system's silent running modes further leverage the low acoustic profile of the electric drive, ensuring reliable power stability that complements onboard guidance functions without compromising performance.^[15]

Warhead and sensors

The Torped 47 features an insensitive munitions (IM)-compliant warhead utilizing a plastic-bonded explosive (PBX) bulk charge weighing over 50 kg, designed for effective anti-submarine warfare (ASW) and anti-surface vessel operations.^[12] This warhead incorporates an IM-classed booster and a safety, arming, and initiation (SAI) unit that meets STANAG standards, ensuring reliable detonation while minimizing risks from unintended stimuli such as impacts or fires during storage, transport, or launch.^[12] The design emphasizes omnidirectional blast effects suitable for engaging submerged or surface targets, with activation triggered by a multi-beam sonar proximity fuse for precise impact or near-miss detonation.^[16] The torpedo's sensor suite centers on a next-generation fully digital homing system with integrated active and passive acoustic capabilities, enabling robust detection and classification of targets in challenging environments.^[12] Key components include a forward-looking sonar (FLS) array operating at higher frequencies than typical ASW torpedoes, optimized for the acoustically complex Baltic Sea conditions such as shallow waters, salinity gradients, and seabed clutter.^[12] This transducer-based system, housed in an electronics unit with flexible beamforming, supports target localization through acoustic reflections and noise signatures, while also facilitating depth measurement and basic obstacle avoidance up to operational depths of 300 meters.^[16] An impact detection loop complements the acoustic sensors for final targeting confirmation.^[12] To enhance reliability against adversarial tactics, the Torped 47 employs advanced signal processing algorithms within its sensor fusion framework, providing resistance to acoustic decoys and jammers through decoy rejection and multi-source data integration.^[16] The system's modular architecture further supports safety by allowing interchangeable warhead and exercise modules, with built-in flotation for post-mission recovery and environmental testing that includes shock, vibration, and drop simulations to validate IM performance.^[16]^[12]

Specifications

Physical characteristics

The Torped 47 is a lightweight torpedo with a total mass of approximately 340 kg, encompassing the warhead and battery components.^[2] Its dimensions include a length of 2,850 mm and a diameter of 400 mm, enabling a compact design that classifies it among lightweight torpedoes suitable for various naval platforms.^[2]^[17] It incorporates modular sections that support efficient maintenance and adaptability, allowing straightforward replacement of components such as the warhead module for exercise variants without altering the core body.^[18]^[8] In configuration, the Torped 47 features a cylindrical body with stabilizing fins for hydrodynamic stability and a pumpjet tail assembly, which includes a ducted rotor/stator setup driven by an electric DC motor.^[17]^[4] This layout contributes to its near-neutrally buoyant profile, optimized for underwater deployment.^[19]

Performance parameters

The Torped 47 achieves a maximum speed exceeding 40 knots in attack mode, enabling rapid engagement of targets in dynamic underwater scenarios.^[2] This performance is supported by its electric propulsion system, which provides efficient power delivery for sustained high-speed operations.^[17] In terms of range and endurance, the torpedo maintains operational capability for more than 20 km at cruising speed, with loiter endurance surpassing 1 hour to support extended search patterns.^[2] It operates effectively at depths up to more than 300 meters, allowing deployment across varied underwater profiles.^[2] The Torped 47 is optimized for challenging environmental conditions, particularly in shallow and cluttered littoral waters such as those of the Baltic Sea, where complex topography and layered water masses prevail.^[3] Its design incorporates a low noise signature, facilitating stealthy approaches and reduced detectability during low-speed maneuvers in high-traffic areas.^[12] The torpedo's modular architecture supports scalability, with provisions for range extensions to at least 50 km through enhancements in battery capacity or guidance systems.^[12]

Operational deployment

Launch platforms

The Torped 47, also known as the Saab Lightweight Torpedo (SLWT), is designed for versatile deployment across multiple platforms, enabling its use in diverse anti-submarine warfare scenarios. Its modular and lightweight architecture facilitates integration with various delivery systems, supporting both manned and unmanned operations through digital fire control interfaces that allow for coordinated multi-torpedo salvos.^[20]^[21] From surface vessels, the torpedo is launched via lightweight tubes or launchers compatible with fast attack craft such as the CB 90-class, corvettes like the Visby-class, and unmanned surface vehicles (USVs). In March 2025, Saab successfully test-fired the Torped 47 from a CB 90 fast assault craft, with demonstrations from a USV following shortly after, during trials in the Baltic Sea, demonstrating plug-and-play integration for rapid deployment on smaller vessels.^[22]^[23]^[24] Submarine launches occur through standard torpedo tubes on platforms such as the Swedish Gotland-class and the upcoming A26-class submarines, with wire guidance enabling precise control during submerged operations. Initial firings from a Gotland-class submarine were conducted successfully in 2020 at Baltic Sea ranges, confirming tube-launch compatibility.^[20]^[8] Air platforms include helicopters, for which the torpedo is prepared for integration, such as on the NH90, allowing wire-guided launches from hovering aircraft without parachutes. It is also compatible with fixed-wing aircraft for aerial drops, as verified in Saab's design specifications for multi-platform flexibility.^[20]^[21]^[16] Stationary launches from shore-based or fixed coastal defense installations provide additional options for static anti-submarine protection, leveraging the torpedo's digital interfaces for integration into land-based fire control systems.^[17]^[25]

Operators

The Swedish Navy serves as the primary operator of the Torped 47, with initial deliveries commencing in 2022 and full integration into service by 2023 across surface vessels, submarines, and airborne platforms to strengthen anti-submarine warfare in the Baltic Sea region. It is planned for integration into the upcoming A26-class submarines. In May 2025, the Swedish Defence Materiel Administration awarded Saab an additional contract valued at SEK 1.3 billion for more Torped 47 units and torpedo tubes, aimed at expanding the inventory with deliveries starting in 2026.^[13]^[19] The Finnish Navy adopted the Torped 47 in 2023, conducting initial acceptance firings from Hamina-class fast attack craft to enhance its anti-submarine warfare capabilities in challenging archipelago environments, where it replaces legacy systems like the Tp 45.^[26] This adoption supports Finland's focus on littoral defense, with the torpedo integrated into ongoing modernization efforts for vessels such as the upcoming Pohjanmaa-class corvettes (expected commissioning in 2027).^[27] As of November 2025, no additional confirmed operators beyond Sweden and Finland exist, though the system has garnered interest from other NATO allies seeking advanced lightweight torpedo solutions for regional security. Total deliveries to both nations have surpassed initial production batches due to follow-on procurements, enhancing interoperability through shared use.^[28]

References

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A torpedo for tomorrow’s needs | Stories | Saab
### Summary of Saab Lightweight Torpedo Development
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Saab Lightweight Torpedo
Technical specifications. Length: 2.850 mm. Diameter: 400 mm. Weight: approx. 340 kg. Speed: 10- more than 40 kts. Endurance: More than 20 km or more than 1 ...
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Saab receives lightweight torpedo order from Sweden
Saab Lightweight Torpedo, named Torped 47 by the Swedish Armed Forces, is Sweden's new light torpedo system aimed at strengthening Sweden's naval defence ...
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Saab Starts Deliveries of New Lightweight Torpedo to Sweden
Oct 17, 2022 · The torpedo has been specially developed for the environment in the Baltic Sea with its shallow water and a complex topography and seabed. These ...
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The lightweight torpedo that's a profound success - Saab
Jan 13, 2022 · The story behind the successful, on-time development of Saab's Lightweight Torpedo is one of teamwork, engagement and trust.
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Jun 9, 2020 · ... Saab 400 mm diameter TS47 is designed to operate in the complex shallow water environment of the Swedish archipelago and the Baltic Sea. The ...
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FMV, Saab demonstrate Torpedo 47 integration on craft of opportunity
Mar 27, 2025 · FMV and Saab have disclosed testing of the new Torpedo 47 (Tp 47) lightweight torpedo from two small 'non-traditional' craft of opportunity.Missing: IM | Show results with:IM
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Swedish Navy receives Saab's Torpedo 47 LWT - Naval News
Dec 21, 2022 · The Torpedo 47 is the fifth generation light torpedo developed in Sweden and replaces the Torpedo 45 currently in service.
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New torpedo introduced into use in the Navy - Finnish Government
Nov 1, 2023 · The system was introduced into use with TP45 model torpedoes in 2020. The propulsion, power supply and target homing systems of the TP47 now ...
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Sweden's torpedo development roadmap charts new heavyweight ...
Mar 10, 2025 · Other potential Torpedo 47 upgrades include a wideband (multi-frequency) acoustic homing head, improved wake-homing performance; replacement of ...
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Jul 6, 2023 · Launch torpedo 47 with wire guidance hovering or as fire and forget. • Use own sensors or relayed information to locate and track target. • ...
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Sweden Tests Torpedo 47 on Combat Boat 90 Highlighting Mobile ...
Mar 28, 2025 · The guidance system features a digital MS4 seeker operating in both active and passive modes, and the torpedo maintains a two-way ...
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Jun 18, 2020 · The wire-guidance and waypoint guidance capability enable the torpedo to navigate any obstacles with minimum undershoot. The search pattern gets ...Missing: Torped limitations
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Successful Tests of New Lightweight Torpedo System
FMV, together with the Swedish Armed Forces and the supplier Saab, has conducted a test firing at sea with torpedo 47 installed on a combat boat 90.Missing: production entry service
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Sweden Successfully Tests Electric Torpedo Launch from Small Boat
Apr 2, 2025 · On March 28, Sweden successfully tested the launch of the lightweight electric Torpedo 47 (Tp 47) from a smaller boat.
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A lightweight torpedo intended for ASW and surface targets, providing multiple-target active/passive homing combined with wire guidance.
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Material and construction of Torpedo. Torpedo's are made from corrosion ... The materials used for making. Torpedos are alloy of aluminium and stainless steel.
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[PDF] Torpedsystem 47
Feb 21, 2019 · Torped 47 is designed so that you only need change one module to change between the warhead- and exercise version, otherwise it is the same ...
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Saab awarded additional Torpedo 47 contract from Sweden - Janes
May 9, 2025 · The SLWT, named Torpedo 47 (Tp 47) by the Swedish Armed Forces, was developed by Saab to replace the legacy Tp 45 weapon in Royal Swedish Navy ( ...Missing: Torped | Show results with:Torped
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Jun 9, 2020 · It is a flexible system that can be launched from multiple platforms, including surface ships, helicopters, fixed-wing aircraft and submarines.
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[24]
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New Torped 47 Lightweight Anti-submarine Torpedo Enters Service
Nov 4, 2023 · Torped 47 can be launched from a variety of platforms including stationary, surface vessels, submarines, helicopters and airplanes like Saab ...<|separator|>
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Finnish Navy Hamina-class FACs conduct first firings of Tp 47 torpedo
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