At SAHA EXPO 2024, Turkiye’s leading naval engineering company, STM, exhibited the pressure hull of the STM500 light submarine, offering attendees a glimpse of the future of shallow-water submarine operations. The displayed section at the exhibition is an actual-size pressure hull of the STM500 submarine, showing a milestone in the project’s development. According to STM representatives at the event, construction of the submarine is proceeding as scheduled, with the project’s timeline remaining on track.
STM first announced the construction of the STM500 submarine on June 26, 2022, emphasizing its focus on shallow-water capabilities and modern submarine warfare requirements.
The STM500 is a 500-ton diesel-electric attack submarine developed by STM as a conceptual design. Its design addresses both classical submarine missions and the growing need for operations in shallow waters. The submarine accommodates a crew of 18 personnel, with space for an additional six Special Forces operatives, and boasts a 30-day endurance while diving to depths greater than 250 meters.
With four torpedo tubes capable of launching a variety of eight modern heavy-weight torpedoes or guided missiles, the STM500 is well-equipped for a range of mission profiles. The platform’s capabilities are further enhanced by its ability to deploy unmanned underwater vehicles (UUVs).
The STM500 will be equipped with various types of advanced sonar systems, including a cylindrical array and cylindrical transducer array, as well as passive ranging, intercept arrays, and own-noise arrays. These sensor systems will feed into the submarine’s combat management system, and it will feature an optronic mast and an electronic support measures (ESM) antenna.
Key Technical Specifications of the STM500
The STM500 boasts an impressive array of technical capabilities, making it a highly effective platform for both conventional submarine missions and modern, shallow-water operations. Key specifications include:
- Length overall: 42 meters
- Maximum beam: 8.50 meters
- Surfaced displacement: 485 tons
- Submerged displacement: 540 tons
- Maximum speed: 18+ knots
- Cruising speed: 5 knots
- Diving depth: 250+ meters
- Endurance on diesel: 3,500 nautical miles
- Endurance on batteries: 75 nautical miles
- Endurance with diesel + AIP: 4,000 nautical miles
The STM500 is powered by a Permanent Excited Propulsion Motor generating approximately 1.5 MW, supported by two diesel generators, lithium-ion batteries, and an optional air-independent propulsion (AIP) system, giving it significant operational flexibility.