The exhaust of every internal combustion engine used on any motorboat needs to be effectively muffled at all times in accordance with Oregon Revised Statute 830.260. The term "effectively muffled" means the exhaust system contains a mechanical device or appliance, designed, constructed and used to reduce the exhaust noise emissions of a motorboat below the maximum noise levels. Such a device or appliance must be integral to the motorboats' exhaust system. Water muffling systems which meet this standard are those which incorporate a marine exhaust manifold.
A person shall operate a motorboat on the waters of this state in such a manner that does not exceed the following noise level:
(a) For engines manufactured before January 1, 1993, a maximum noise level of 90 dBA when subjected to a stationary test as prescribed by SAE J-2005_199112;
(b) For engines manufactured after January 1, 1993, a maximum noise level of 88 dBA when subjected to a stationary test as prescribed by SAE J-2005_199112;
(c) A maximum noise level of 84 dBA measured as specified in the shoreline sound level measurement procedure for recreational motorboats SAW J-1970_201102.
(3) This regulation shall not apply to motorboats competing, under a permit issued by the Marine Board pursuant to ORS 830.375 or a United States Coast Guard permit, in a regatta, a boat race, or while on official trials for speed records during the time and in a designated area authorized by the permit; and those boats testing in areas designated by the State Marine Board pursuant to ORS 830.350.
A weighted decibel, abbreviated dBA, is an expression of the relative loudness of sound in air as perceived by the human ear. In the A-weighted system, the decibel values of sound at low frequencies are reduced, compared with unweighted decibels, in which no correction is made for audio frequency.
The Marine Board does not have authority to regulate for noise outside of internal combustion engines. Loud noise from stereo systems is a major source of complaints the Marine Board receives, so keep stereos turned down to avoid potential legislation.