Sound
Despite the fact that the boating industry manufactures its products to meet all applicable sound standards, noise can be an area of conflict with some waterfront residents. In response to the demand for quieter watercraft, the boating industry is producing new products that are significantly quieter than those produced just one year ago.
Recent Technological Breakthroughs Result in Quieter Watercraft
Because of recent technological breakthroughs, marine engine manufacturers are now able to design both two-and four-stroke engines that offer significant reductions in noise the result being a quieter watercraft. Additionally, manufacturers are rerouting the exhaust system and incorporating resonators that block and cancel out both intake and exhaust noise. They are also incorporating rubber driveline dampers, rubberized engine mounts, thicker engine crankcase walls, hull liners, absorbing foam and other noise suppression materials to reduce vibration and other noises that get transmitted through the hull. This new sound reduction technology reduces watercraft noise significantly. Manufacturers report that many new 1999 watercraft are 50-70 percent quieter than the similar 1998 models.
The National Marine Manufacturers Association Supports Quieter Use Practices
The National Marine Manufacturers Association (NMMA) recognizes that noise is an issue for everyone who enjoys the water. The boating industry has conducted extensive research into the complaints about boat noise, and findings indicate that with proper equipment and courteous operation, complaints about boat noise can be virtually eliminated. In an effort to make all boaters more aware of the necessity to operate their vessels in a quieter manner, the NMMA provides boaters and consumers with tips on how to reduce noise levels.
Sound Measurement
The standard unit by which sound is measured is dB (A) and it is used by all government agencies responsible for protecting health and enforcing state and local noise standards. By conducting sound measurements in dB (A), the fact that the human ear is more sensitive to some frequencies and pitches is taken into account. This is accomplished through a "weighting" of some frequencies over others to simulate normal sensitivities of the human ear. This weighting is called the "A" scale, and sound measurements recorded in this way are expressed as dB (A).
