The phrase "gone Davy Jones's locker" is a nautical term used to describe a situation where a ship or individual has sunk or died at sea. Some synonyms for this phrase include "lost at sea," "perished in the deep blue," "sunk to the bottom," and "sent to a watery grave." These phrases are often used to describe tragedies that occur at sea, and can be used in both literal and metaphorical contexts. It is important to carefully consider the context in which these phrases are used to ensure that they are appropriate and respectful to those affected by the event in question.