Maritime navigation is a crucial aspect of seafaring. To ensure the safety of ships and their crews, it is essential to provide proper notice to mariners about any potential hazards and other important information. Some synonyms for "notice mariners" include "inform seafarers," "advise sailors," "notify navigators," and "alert boaters." These phrases all convey the idea of providing crucial information to those on the water, allowing them to take appropriate action and avoid any potential dangers. By using clear and concise language when communicating with mariners, we can help keep them safe and ensure smooth sailing on the open sea.