Posted to News on 24th Jul 2026, 10:00
Structural vibration sensor meets the extreme demands in naval applications
Keeping a submarine silent is one of the most demanding engineering challenges in naval design. Every pump, turbine and fan on board generates vibration, and if that energy reaches the hull, it radiates into the water as sound, which in turn is picked up by enemy sonar. Managing this "acoustic signature" is central to submarine stealth, and it depends on being able to measure structural vibration accurately, continuously, and in some of the harshest operating environments in the world. That's where Sensonics' QZA accelerometer comes in.
The Sensonics QZA design originated during the late Cold War submarine programme era and remains a core part of Hull Vibration Monitoring Equipment (HVME) fitted to Royal Navy vessels, as well as other NATO navies.
The QZA is built around high-performance piezoelectric technology, chosen for its ruggedness, long-term stability, and suitability for the extreme conditions found on board a warship or submarine. This is fundamentally a structural vibration sensor, not a condition-monitoring device in the traditional industrial sense. Its primary role is to measure how much vibration energy is present in the hull and machinery structure, feeding that data into the vessel's HVME system so crews can understand and manage their acoustic footprint. The condition of the machinery generating that vibration is part of the picture, but not the main purpose of the sensor.
Built to survive combat conditions
The QZA is permanently mounted to the hull and machinery rafts using a heavy-duty, four-point flange system, engineered to maintain a rigid, high-fidelity mechanical connection even under the extreme shock loading a warship may experience.
This mounting approach also allows the stainless-steel housing to be bolted directly to bare metal without introducing electrical ground loops, since the internal sensing element is fully isolated from the case.
The sensor's output is a 50 uA/g constant current signal rather than a voltage signal, a deliberate design choice for naval applications, where cable runs to the central processing rack can extend up to 100 metres through electromagnetically noisy environments. A current loop output is inherently resistant to cable resistance losses, high-frequency roll-off, electromagnetic interference, and triboelectric noise from cable flexing, ensuring the vibration data reaching the HVME processing system remains clean and accurate however far it has travelled.
Supporting the mission, not just the machine
By continuously monitoring both auxiliary machinery and the main propulsion train, QZA sensors allow HVME systems to flag when vibration levels move outside expected limits, giving crews the information they need to maintain their acoustic signature, plan maintenance, and ultimately protect the safety and effectiveness of the vessel and its crew.
The QZA is available in several configurations, including versions with an integral connector and versions with integral flexible conduit of various lengths, all listed under NATO Stock Numbers. With decades of continuous service across the Royal Navy and allied fleets, the QZA accelerometer remains a proven, dependable choice for structural vibration monitoring in the most demanding of naval applications.
