Engineering Solutions to Noise and Vibration Problems

Underwater Noise Measurement

Noise Control Engineering is the first private non-government organization in the U.S. to offer measurement of ship underwater noise. This is done with a proprietary system called BAMS™: the Buoy Acoustic Measurement System. Using BAMS™, NCE can provide calibrated underwater source sound pressure level measurements to compare with a criteria or another ship.

Why Measure a Ship's Underwater Noise?

Features and Benefits of BAMS™

Calibrated Measurements Performed to Industry Standards

Cutting Edge State-of-the-Art Technology

Best System for Compliance or Diagnostic Testing

Comparison of Underwater Radiated Noise between NCE BAMS™ and Permanent Range

The figure shows a comparison between the underwater radiated noise of a research vessel measured with a permanent hydrophone array and with BAMS™. The general correlation between measurements is very good. Small deviations on the order of 1 dB are seen at specific frequencies between 25 and 20,000 Hz. The difference at 20 Hz is due to variations in operating machinery between measurements, while differences at 10 and 12.5 Hz are attributed to hydrophone motion during the BAMS™ measurement.

(click to enlarge)

Both measurements were performed using the basic test framework outlined in ANSI/ASA S12.64 [1]. The subject of the measurements is a research vessel with a relatively low underwater noise signature as compared to common commercial vessels such as tug boats, tankers, platform supply vessels, etc. Although the absolute magnitude of the spectrum cannot be shown, the scale is shown with 5 dB per division.

[1] Det Norske Veritas, "Silent class notation, Newbuildings, Special Equipment and Systems: Additional Class," Norway, 2010.