PART 86—ANNEX III: TECHNICAL DETAILS OF SOUND SIGNAL APPLIANCES Authority: Sec. 303, Pub. L. 108-293, 118 Stat. 1042 (33 U.S.C. 2071); Department of Homeland Security Delegation No. 0170.1. Source: 79 FR 37924, July 2, 2014, unless otherwise noted. § 86.01 Whistles. (a) Frequencies and range of audibility. (b) Limits of fundamental frequencies. (i) 70-200 Hz, for a vessel 200 meters or more in length. (ii) 130-350 Hz, for a vessel 75 meters but less than 200 meters in length. (iii) 250-700 Hz, for a vessel less than 75 meters in length. (c) Sound signal intensity and range of audibility. 1/3 Table 86.01( c Length of vessel in meters 1 3 −5 2 Audibility range in 200 or more 143 2 75 but less than 200 138 1.5 20 but less than 75 130 1 Less than 20 1 2 3 0.5 1 2 3 (d) Directional properties. 1/3 rd (e) Positioning of whistles. (ii) A whistle shall be placed as high as practicable on a vessel, in order to reduce interception of the emitted sound by obstructions and also to minimize hearing damage risk to personnel. The sound pressure level of the vessel's own signal at listening posts shall not exceed 110 dB(A) and so far as practicable should not exceed 100 dB(A). (f) Fitting of more than one whistle. (g) Combined whistle systems. (ii) The whistles of a combined system shall: (1) Be located at a distance apart of not more than 100 meters; (2) Be sounded simultaneously; (3) Each have a fundamental frequency different from those of the others by at least 10 Hz; and (4) Have a tonal characteristic appropriate for the length of vessel which shall be evidenced by at least two-thirds of the whistles in the combined system having fundamental frequencies falling within the limits prescribed in paragraph (b) of this section, or if there are only two whistles in the combined system, by the higher fundamental frequency falling within the limits prescribed in paragraph (b) of this section. Note to paragraph ( g If, due to the presence of obstructions, the sound field of a single whistle or of one of the whistles referred to in paragraph (f) of this section is likely to have a zone of greatly reduced signal level, a combined whistle system should be fitted so as to overcome this reduction. (h) Towing vessel whistles. § 86.02 Bell or gong. (a) Intensity of signal. (b) Construction. § 86.03 Approval. [Reserved]