46 C.F.R. § 151.45-9 Signals.
Title 46 - Shipping
While fast to a dock, a vessel during transfer of bulk cargo shall display a red flag by day or a red light by night, which signal shall be so placed that it will be visible on all sides. When at anchor, a vessel during transfer of bulk cargo shall display a red flag by day, placed so that it will be visible on all sides. This flag may be metallic.
Title 46: Shipping
PART 151—BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES
Subpart 151.45—Operations
§ 151.45-9 Signals.
