Section 306.090 - Maximum sound levels for recreational motorboats - exceptions1. It is unlawful for any person to operate a recreational motorboat upon the waters of this state in any manner under any condition so that the recreational motorboat emits sound at a level exceeding eighty-six decibels on an A-weighted scale when measured from a distance of fifty or more feet from the recreational motorboat.2. This section shall not be construed so as to prohibit use of any exhaust system or device, including but not limited to those not discharging water with exhaust gases as long as the device or system emits sound at a level in compliance with subsection 1 of this section.3. The provisions of this section do not apply to motorboats operated under permit pursuant to section 306.130, nor to trial runs for a period not exceeding the twenty-four hours immediately preceding a regatta or race, nor to official trials in competition for speed records for a period not exceeding the twenty-four hours immediately preceding a regatta or race.L. 1959 S.B. 142 § 7, A.L. 1977 S.B. 151