About

About Tethys ONE

Tethys ONE is a 35 kg underwater vehicle rated to 300 metres and designed to hold position in currents up to approximately 3.5 knots. It can operate through a tether at ranges of 400 metres or more, while hot-swappable batteries support roughly four hours of operation. Autonomous functions include repeatable area coverage, structure scanning, depth hold and distance lock.

Operators can pilot the robot directly for close inspection or use autonomous coverage and sonar-assisted mapping where visibility is poor. Modular cameras, sonar, lights and inspection sensors adapt the system to offshore wind, civil infrastructure, search and rescue and explosive-ordnance work. A ten-minute setup and compact control station allow deployment from smaller vessels without the cranes and containerised workshops used by conventional work-class ROVs.

Timeline

Aramco Europe completes Tethys ONE lake demonstration
2025-10-16 - Demonstration - Aramco Europe described the Swiss-lake demonstration as completed. The Tethys-supplied unit was evaluated for automated inspection of complex underwater infrastructure. A real-facility test in Saudi Arabia was a next step, not yet a completed deployment.
Source
Tethys names SepcoTech as Denmark partner for subsea systems
2025-07-29 - Partnership - SepcoTech was named as Tethys' new partner in Denmark. The collaboration targets defence and offshore inspection applications. The announcement describes market representation, not a completed customer sale or deployment.
Source
Tethys Robotics releases new Tethys ONE underwater drone
2024-08-22 - Product Launch - The 35-kilogram system combines pilot-controlled ROV operation with autonomous AUV operation. Tethys specified operation to 300 metres and position holding in currents up to 3.5 knots. The modular payload architecture supports cameras, acoustic sensors, metal detection, UT, XRF and manipulators.
Source

Context

Comparable Systems

Aquanaut
Nauticus Robotics - Hybrid Rov Auv
Sabertooth
Saab - Hybrid Rov Auv