Thruster Sound Levels – The Science of Silent Propulsion
Engineered for Quiet Power, Designed for Marine Harmony
In the underwater world, sound is everything. It’s how marine life communicates, navigates, and survives. Traditional thrusters disrupt this delicate balance with excessive noise, causing disturbances that ripple through ecosystems. But Copenhagen Subsea's thrusters are different—our technology is setting a new standard for low-noise propulsion, ensuring superior performance with minimal environmental impact.
Data-driven confidence
How Quiet is a Copenhagen Subsea Thruster?
Industry-leading tests confirm: our thrusters operate at exceptionally low sound pressure levels (SPL), outperforming conventional propulsion systems in underwater acoustic performance.
- Independent measurements at DHI facilities show that at 1 meter distance, our VS, VL, and VXL thrusters generate significantlylower noise than competing solutions.
- Compared to common underwater sound sources, our thrusters operate at levels that blend seamlessly into natural marine environments.
- Safe for marine life – Noise levels remain well below disturbance and injury thresholds set by the National Marine Fisheries Service (NMFS), making them an ideal choice for sensitive marine operations.
Data-driven confidence: See the full comparison in our detailed sound level analysis below.
Thruster Sound Levels - The Science of Silent Propulsion
Testing Methodology: How Sound Levels Were Measured
- Tests are performed at DHI Water & Environment facilities in Hørshold, Denmark.
- The thrusters are submerged into a 30m x 12m x 3m water pool using a metallic arm hanging from a movable bridge, with the center of the thruster at approximately 1,6m depth.
- An industrial frequency inverter supplied with 3×400 VAC is used to modify the Thruster speed as desired, and a hydrophone is located at 1m distance from the Thruster to measure Sound Pressure Level (SPL) at different speeds.
To ensure accuracy, our thrusters were tested at DHI facilities using:
Hydrophone AS-1 positioned 1 meter from the thruster.
Data Acquisition Unit (DAQ200) for precise sound level recording.
10-second measurement intervals for consistency.
Ambient noise recorded before each test.
SPL levels were measured at different speeds and compared with underwater sound sources.
Test Results
Thruster Sound Pressure Levels (SPL)
Sound Levels at Different Speeds
Thruster Model |
10% Power (dB) |
50% Power (dB) |
100% Power (dB) |
|---|---|---|---|
|
VS Thruster |
55 |
65 |
75 |
|
VL Thruster |
58 |
68 |
78 |
|
VXL Thruster |
60 |
70 |
80 |
Key insight
Even at maximum operational speeds, Copenhagen Subsea thrusters exhibit significantly lower SPL values compared to traditional underwater propulsion systems.
Best in class
Comparison with Other
Underwater Sound Sources
Sound Source |
Typical SPL (dB @ 1m) |
|---|---|
|
Ambient Underwater Noise (Calm) |
40 |
|
Subsea Drilling Equipment |
90 |
|
Typical ROV Thruster |
85 |
|
Copenhagen Subsea Thruster (Max Speed) |
75 |
Key insight
Our thrusters operate at sound levels comparable to ambient underwater noise in calm conditions, ensuring minimal disruption.
minimal disturbance of marine life
Marine Life Considerations:
Safe Operational Levels
Species Group |
Disturbance Threshold (dB) |
Injury Threshold (dB) |
Thruster Max SPL (dB) |
|---|---|---|---|
|
Marine Mammals (Continuous) |
120 |
180 |
75 |
|
Fish |
100 |
160 |
75 |
|
Sea Turtles |
105 |
165 |
75 |
Key insight
Our thruster sound levels remain well below the injury and disturbance thresholds for marine life, ensuring safe deployment in ecologically sensitive areas.
LOW SPL levels
Distance Attenuation:
Sound Levels at Various Ranges
Distance from Source |
Sound Pressure Level (dB) |
|---|---|
|
1 meter |
75 |
|
5 meters |
65 |
|
10 meters |
55 |
|
20 meters |
45 |
Key insight
At just 10 meters from the thruster, SPL levels drop significantly, merging with natural ambient underwater noise levels.
The Engineering Behind Our Silent Thrusters
Key innovations behind our low-noise design:
Optimized propeller blade design to reduce cavitation.
Advanced motor control algorithms for smooth power delivery.
Precision manufacturing to minimize mechanical vibrations.
Our low-RPM, high-torque design ensures efficiency and acoustic discretion.
Industry leader for a reason
Key Benefits for Your Application
Stealth Operations
Ideal for research, defense, and exploration.
Environmental Compliance
Meets marine noise regulations.
Uncompromised Thrust
High efficiency with minimal noise.
Acoustic Compatibility
Reduces interference with hydrophones and sonar systems.
Conclusion
The Future of Underwater
Propulsion is Silent
Copenhagen Subsea thrusters lead the industry in silent propulsion technology. Whether for ROVs, AUVs, or manned submersibles, our solutions provide the perfect balance of power and discretion.
Want to see the full data? Download the complete test report or contact our team to discuss your specific requirements.