The exhaust of every internal combustion engine used on any motorboat shall be effectively muffled by equipment so constructed and used as to muffle the total vessel noise in a reasonable manner in accordance with rules adopted by the commission. The use of cut-outs is prohibited, except for motorboats competing in a regatta or boat race approved as provided in section 462A.16 and for such motorboats while on trial run during a period from 8:00 a.m. to 6:00 p.m. not to exceed twenty-four hours immediately preceding such regatta or race. [C39, § 1703.11, 1703.17; C46, 50, 54, 58, §106.11, 106.17; C62, 66, 71, 73, 75, 77, 79, 81, §106.11 ; 82 Acts, ch 1028, §14 ] C93, §462A.11 Referred to in §805.8B(1)(b) For applicable scheduled fines, see §805.8B , subsection 1, paragraph b