This maritime sign is used by mariners to provide adequate signage on board vessels. Furthermore, some flag states and regulatory organizations require maritime signs on board to be in compliance with the maritime governing regulations. Maritime signs are critical in keeping a vessel's crew safe of any possible hazards, all safety equipment easy to mark, and provide directions on board a vessel.
MARPOL Annex V, Regulation 10 requires certain ships to use placards and plans to advise passengers and crew of garbage disposal regulations.