A shipmate is literally a mate on one's own ship. In English-Speaking navies and the United States Coast Guard, the term "shipmate" is used among sailors as a generic moniker. It is used in the third person by a member of a ship's crew to describe another member, or in the second person when referring to any other Naval service member. In the United States Navy, "shipmate" is most accurately a term used by anyone in the Navy to reference anyone else in the Navy. It can be used with a range of connotations—most often as an expression of camaraderie, but also as a respectful way to address other crew members whose rank or naval rating is not obvious. It can even be used in a derogatory manner. It is used both on land and at sea and it is used among Naval service members without regard to whether they are in fact members of the same ship. The term is used so abundantly in the American Navy that the inflection, context, and tone of the speaker can connote more meaning than the term itself. In the United States Navy, recruits are indoctrinated with heavy use of the term immediately upon beginning training at Recruit Training Command. There, they use the term abundantly to refer to their peers in all but the least formal settings. Notably, recruits use the term superfluously and with enthusiasm to sound off to their peers in scenarios when referencing another person by name or title would be otherwise unnecessary. For example, a recruit in the chow line will add "shipmate" after identifying each item of food he or she wishes fellow recruits to place on his or her tray. In turn, the recruits serving his or her food will repeat the expression as the recruit moves down the line "potatoes, Shipmate!", "green beans, Shipmate!", "bread, Shipmate!"... to confirm that they understood the commands. It is used so abundantly during this stage of a sailor's training that it can sound curious to a new recruit or a visitor. The term is almost never used by superiors to refer to inferiors during recruit training except ironically or in a derogatory tone. Sometimes the term is modified to connote the derogation more explicitly, as in "Shipwreck" in reference to someone who is messy or fails to maintain a military bearing. As the extreme hierarchical distinctions in recruit training tend to fade once the recruit joins the regular Navy, so do the above distinctions. It is not uncommon to hear an Admiral or Captain refer to his lowest subordinates as "shipmate" in order to express camaraderie. Inversely, it is not uncommon for peers to refer to one another as "shipwreck" or use a vocal inflection that connotes derogation, usually with an accent on the "-mate." The term is often used in a follow-on training status such as "A" School from superiors to their subordinates to point out deficiencies, usually when rank of the subordinate is not easily identified. An example would be "Hey shipmate! Fix your uniform!" The use of the term in this context would be similar to a division commander referring to a recruit as "Recruit". Although the term is not commonly used outside maritime scenarios, it is often used by Navy veterans toward one another as a means to reminisce or bond about shared experience.
Usage in literature
's Moby-Dick, a popular maritime novel, is laced with the term, although the narrator Ishmael seldom uses the word: "This man interested me at once; and since the sea-gods had ordained that he should soon become my shipmate, I will here venture upon a little description of him."
Usage in contemporary maritime dialogue
One might refer to a fellow crew member by saying, "He and I were shipmates before reporting for duty here in Norfolk." The word is used in this sense in the old song "Don't Forget Your Old Shipmates". When getting the attention of a fellow sailor, one might simply call out "Shipmate!" or "Hey, shipmate!" When speaking to a group or crowd of sailors, i.e. "My fellow shipmates..."
