33 C.F.R. Subpart B—Bell or Gong
Title 33 - Navigation and Navigable Waters
A bell or gong, or other device having similar sound characteristics shall produce a sound pressure level of not less than 110 dB at 1 meter. Bells and gongs shall be made of corrosion-resistant material and designed to give a clear tone. The diameter of the mouth of the bell shall be not less than 300 mm for vessels of more than 20 meters in length, and shall be not less than 200 mm for vessels of 12 to 20 meters in length. The mass of the striker shall be not less than 3 percent of the mass of the bell. The striker shall be capable of manual operation. Note: When practicable, a power-driven bell striker is recommended to ensure constant force.
Title 33: Navigation and Navigable Waters
PART 86—ANNEX III: TECHNICAL DETAILS OF SOUND SIGNAL APPLIANCES
Subpart B—Bell or Gong
§ 86.21 Intensity of signal.
§ 86.23 Construction.
