What Is CAPTAS? Thales’s Submarine-Hunting Variable-Depth Sonar
CAPTAS is Thales’s “variable-depth sonar” (VDS) family, lowered into the water from warships, and one of Europe’s reference systems for submarine hunting. Its body is towed behind the ship like a trailer and can be lowered to a chosen depth, designed to catch silent submarines hiding beneath the ocean’s temperature layers. Trusted by 18 navies, the family has passed 100 orders.
What Is CAPTAS?
Short for “Combined Active and Passive Towed Array Sonar,” CAPTAS is one of the most critical sensors in anti-submarine warfare (ASW). Its core idea solves a problem a hull-mounted sonar cannot: in the ocean, temperature and salinity bend sound at different depths, and a submarine can hide in these “acoustic shadows.” CAPTAS’s variable-depth body (VDS) descends right beneath that shadow to hunt the submarine. The family comes in three versions scaled to ship size: CAPTAS-1, CAPTAS-2 and the most powerful, CAPTAS-4.
Technical Specifications (based on CAPTAS-4)
| Feature | Value |
|---|---|
| System type | Active/passive variable-depth towed sonar (VDS) |
| Manufacturer | Thales |
| Active body | UMS-4249, ultra-low-frequency sonar with four ceramic rings |
| Active frequency | 900–2100 Hz |
| Immersion depth | up to 300 metres |
| Typical detection range | up to 150 km |
| Coverage | 360° simultaneous active/passive surveillance + permanent torpedo alert |
| Versions | CAPTAS-1 / CAPTAS-2 / CAPTAS-4 (by ship size) |
Who Operates It?
The CAPTAS family is used by 18 navies worldwide, with more than 100 systems ordered or in service. The CAPTAS-4 equips the FREMM frigates of France, Italy, Egypt and Morocco and Spain’s F110 frigates. In the UK it serves on the Royal Navy’s anti-submarine frigates under the name “Sonar 2087.” Operators include major navies such as France, Italy, the United Kingdom and the United States.
Competing Systems
CAPTAS’s main rivals are other Western makers in the variable-depth sonar market: systems from Raytheon/DRS in the U.S., ASW sonars from Swedish and other European firms, and ASELSAN’s indigenous variable-depth sonar (DÜFAS) in Türkiye. DÜFAS forms the Turkish Navy’s domestic alternative in this field.
Relevance to Türkiye
Türkiye has turned to ASELSAN’s indigenous DÜFAS system for ASW sonar, so CAPTAS is not a system the Turkish Navy has adopted. Even so, CAPTAS is one of the most important international rivals and benchmarks for Türkiye’s home-grown sonars, frequently cited in technical comparisons.
Frequently Asked Questions
- What does CAPTAS do? It is a variable-depth towed sonar, lowered from a ship into the water, that detects silent submarines.
- Why does variable-depth sonar matter? It descends beneath the acoustic layers where submarines hide, finding targets a hull-mounted sonar cannot.
- How deep does the CAPTAS-4 go? Up to 300 metres, with a typical detection range up to 150 km.
- How many navies use it? 18 navies, with more than 100 systems ordered or in service.
- What is the UK’s “Sonar 2087”? It is the British variant of the CAPTAS-4 used by the Royal Navy.
