CFR › Title 49 › Part 176 › §176.17649 CFR §176.176Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗Copy linkWhen Class 1 (explosive) materials are being loaded, handled, or unloaded on a vessel, the vessel must exhibit the following signals:(a)By day, flag “B” (Bravo) of the international code of signals; and(b)By night, an all-round fixed red light.