John Partridge founded Sonardyne in 1971 and his vision was to improve the safety and efficiency of underwater navigation for divers through innovation in acoustic signal processing, hardware design and custom engineering.  From our origins in the North Sea in the early 1970s, innovation and performance has maintained our reputation for technical leadership. Today we have an unrivalled portfolio of acoustic and non-acoustic technologies for use in the most challenging marine environments. Our vision is to facilitate safe, secure, economical and environmentally sound operations upon and within the world’s oceans and seas; continuing  to expand on  John’s original vision.

Whilst underwater acoustics remains at the very core of what we do, our business now reaches far beyond this, driven by both the possibilities of new technologies and the needs of our clients.   In just a few short years sonar imaging, optical communications and inertial navigation technologies have emerged from our research programmes. But if experience has taught us one thing, it is that the more you understand about your client’s business, then the more responsive you can be as an organisation and the better prepared you are to deliver and support the right solution. Our investment has provided great value to our customers. Survey operations become ever faster and more efficient, deepwater vessels are able to operate safely in all conditions, seabed to surface data transfer is reliable and quick and waterside installations are better protected against the threat of attack.



  • Detects divers and underwater vehicles approaching your marine asset
  • Perfect for yachts, harbours and waterside facilities
  • Rapidly deployed for instant protection
  • Stand alone or networked operation

Close the gap in your situational awareness by specifying the world’s most widely deployed underwater intruder detection sonar, Sentinel, to help safeguard your maritime assets.

Whether it’s protecting a commercial harbour, naval vessel, private yacht, critical national infrastructure (CNI) facility or waterside residence from the threat of attack, Sentinel is cost-effective, easy to operate and proven in all theatres of operation.


Sentinel detects, tracks and classifies divers and autonomous underwater vehicles (AUVs) approaching a protected asset from any direction and alerts security personnel to the threat. With the ability to identify targets at ranges of up to 1,500 metres*, Sentinel takes reliable, long range underwater intruder detection to a new level and since its introduction, has been used in CNI, vessel and VIP protection duties around the world.

Sentinel is small and lightweight so is quick to deploy from a boat, install in a port or fix along a coastline – providing you with an instant underwater security shield. We’ve engineered all the complexity associated with configuring and operating advanced sonar technology into easy-to-use software meaning that your security personnel don’t need to be sonar experts to use it. In fact, once it’s set up, Sentinel can be left to run autonomously.


The base system, Sentinel, is configured to meet the needs of commercial and infrastructure facility protection projects. It can be used as a standalone security sensor or integrated with third party command and control (C2) security systems. Support for networked sonar is also offered, meaning that entire waterfronts can be protected using a single operator station.

Our Sentinel Expeditionary System is a portable diver detection sonar (PDDS). Its small topside footprint means it’s perfect for short term operations using offshore patrol vessels (OPVs) and temporary sites on shore. We also offer a military-only variant not available to private or commercial users.

*Depending on environmental conditions and product variant. 900 metres range for divers

Get in Touch


Click to email