Uniform

Phonetic alphabet letter U.

Warning of Danger: When a vessel displays the Uniform flag, it serves as a warning to another vessel that it is approaching or heading towards a potentially hazardous situation or area. This could include shallow waters, navigational hazards, or dangerous conditions like rocks, reefs, or submerged objects.

Flag

Code Flag Uniform (U)

Nautical or signal flags are used at sea to convey messages over long distances. Only black, blue, red, white and yellow are used because these are the only colours readily distinguished at sea. Many different coding schemes have been used, but the International Code is the most common.