Engineering Solutions to Acoustic Problems

Underwater Noise

Underwater noise for non-military applications has gained significant importance in the last ten years, particularly for vessels operating in environmentally sensitive areas. NCE has extensive experience in the design of such vessels which may include research vessels, tugboats, offshore supply vessels (OSV's) and other military vessels. Notable projects in this area are the acoustically quieted Fisheries Research Vessel (FRV) for National Oceanic and Atmospheric Administration (NOAA) and a quiet general research vessel for the University of Delaware, R/V HUGH R. SHARP. For further details use link to see the project portfolio or go to that page.

NCE offers analysis, design and testing services for the prediction and reduction of shipboard underwater noise levels. NCE can also evaluate other marine platforms such as offshore oil rigs. NCE uses Designer-NOISE™ to predict underwater noise levels which allows for determination of the critical noise path. This allows for effective selection of noise control treatments. NCE can perform underwater noise analysis and treatment evaluations and/or trade off studies during concept or detail design stages.

Whether specific underwater noise requirements need to be achieved (such as ICES CRR 209) or your vessel must operate quieter, NCE can provide engineering services during the early design phase of noise critical ships. We have underwater noise prediction tools such as Designer-NOISE™ and a large database of machinery noise and vibration (source) levels and underwater noise levels from various types of ships. This along with many years experience, allow NCE to generate accurate estimates of a ship's underwater noise from preliminary design information (usually, General Arrangements, Machinery Arrangements, Typical Structural Section, and Insulation Detail). Contact NCE for an exact list of required technical information.

In cases where requirements are not achieved, NCE will offer recommendations for noise reduction. Our approach is to recommend treatments with the highest reduction at lowest cost. However, in many cases integrated set of noise control treatments may be needed. Such treatments include vibration isolation, acoustic insulation, hull damping, and pipe attenuation devices. NCE has a large database of noise control treatment attenuation from both our own use and from the vendors themselves. Using the above tools, NCE can provide trade-off studies and cost-benefit analysis for a quiet ship design.

The construction of a quiet ship requires more than just a quiet design. Many of the noise control treatments can impact other factors in the vessel design such as space, weight, maintenance. Further, installation of the materials can be critical to final performance. Because treatment installation and ship construction are critical to vessel's eventual noise, NCE provides both training and vessel inspection services. NCE can train construction personnel in the important aspects of building quiet ships. Generally such training is important for engineering, quality control, supervisors and foremen. NCE also conducts inspections of noise critical ships during construction. Such inspections are performed during major machinery installation and insulation installation.

After the design and construction of a quiet vessel, verification may be required, usually for contractual reasons. NCE has the instrumentation and methodology to measure the underwater noise from ships or other marine structures in any open water location. Measurements are performed using "commercial-off-the shelf" (COTS) technology. NCE has conducted underwater noise measurements in the Atlantic & Pacific Oceans, Gulf of Mexico, Puget Sound and abroad. NCE can also serve as owner representative, if more rigorous measurements by the U.S. Navy are desired. NCE can arrange underwater noise surveys at U.S. Navy facilities on both East and West Coasts.