Code of Federal Regulations Title 33. Navigation and Navigable Waters § 33.67.10–10 Operating requirements

(a) Sound signals required by §§ 67.20–10, 67.25–10, and 67.30–10 must be operated continuously, regardless of visibility, unless the sound signal is controlled:

(b) During construction and until such time as a sound signal is installed and operating on a platform, the whistle of an attending vessel moored alongside the platform may be used to sound the signal required for the structure by this part.