Engineering Solutions to Acoustic Problems
Any ship, whether it is a small workboat or a military aircraft carrier, can be a very noisy place; ask anyone who works on one. Smaller vessels (60 to 300 feet) have high power machinery (diesel engines, pumps, large hydraulic systems) just feet away from sleeping cabins, offices and control rooms causing high noise levels. Larger vessels can also have high noise in compartments near large machinery and propeller/thruster sources. HVAC and other auxiliary machinery or specialized sources (such as aircraft) can also be an important factor elsewhere in the vessel. Noise control is a critical factor for the marine industry, since quiet ships lead to improved crew morale, lower long-term hearing loss, improved crew performance, and reduced crew fatigue.
NCE is a leader in the field of Marine Acoustics. We have provided technical assistance on hundreds of vessels; our clients include naval architects, shipyards, government organizations, and private owners and operators. NCE's staff has authored more than 50 papers on shipboard noise, including the "Design Guide for Shipboard Airborne Noise Control", an industry standard published by the Society of Naval Architects and Marine Engineers in 1983 and its Supplement sponsored by the U.S. Coast Guard published in 2000.
Services offered to Naval Architects, Shipyards and Marine Operators are:
AIRBORNE NOISE ANALYSIS
Accurate noise predictions anywhere on a vessel can be performed based on a ship's general arrangement, typical structural details and machinery arrangements and details. NCE uses our own Designer-NOISE and other software products/tools (many of which were developed in-house) for the prediction and control of shipboard noise. For more information, go here.
NCE can predict potential low frequency 'habitability' and structural vibration problems using various tools including Finite Element Analysis (FEA). Analyses can be performed on a local or global level, with models ranging from specific foundations to masts to engine rooms to entire vessels. For more information, go here.
UNDERWATER NOISE ANALYSIS
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 predicting and controlling underwater radiated noise levels. For more information, go here.
MEASUREMENT & DIAGNOSTIC SURVEYS
NCE is highly experienced in the measurement of shipboard noise and vibration. NCE has conducted numerous on-site noise and vibration surveys. Our extensive test experience includes airborne noise, vibration testing, underwater radiated noise and sonar self noise. For more information, go here.
ABS ENVIRONMENTAL TESTING SPECIALIST
NCE holds an external specialist certification in "Ambient Environmental Testing" from the American Bureau of Shipping (ABS). We are the only company in North America and only one of four companies in the world to acquire such a certification. The certification includes measurements of noise, vibration, lighting, temperature and relative humidity for those seeking HAB, HAB+, COMF, or COMF+ notations. For more information, go here.
SONAR SELF NOISE ANALYSIS
Sonar-self noise is the sound of a vessel's machinery that is picked up from the vessel's hull mounted hydrophones. High self-noise interferes with optimally running sonar systems. NCE can predict the levels of self-noise to be compared with a sonar vendor's specifications. In addition, noise control treatments exist to mitigate such problems. For more information, go here.
NOISE CONTROL TREATMENT DESIGN
NCE selects optimal noise treatments based on a comprehensive sound and vibration analysis described above. A few of the treatments include: vibration isolators (see section below & details), acoustical insulation, damping, floating floors and silencers. For more information, go here.
MACHINERY VIBRATION ISOLATION
Machinery structureborne vibration is one of the biggest sources of noise in ships. An effective way to reduce noise, is to mount the offending equipment on vibration isolators. However, the isolation system needs to be properly designed and implemented or vibration can get worse. For more information, go here.
SERVICES FOR OFFSHORE PLATFORMS
Offshore structures, ranging from fixed platforms to semisubmersibles to FPSOs, can have noise and vibration problems similar to those found on ocean going vessels. Although the functions required of these structures varies significantly, the mechanisms that govern the creation, spreading, and radiation of sound and vibration are often quite similar, and are also similar to those found on vessels. For more information, go here.