One of the more interesting uses of this vocative in literature occurs in Herman Melville’s Moby Dick. Ishmael attends the Whalemen’s Chapel in New Bedford and hears the sermon delivered by Father Mapple, a former sailor and harpooneer...

A shipmate is literally a mate on one's own ship, ie. a member of the same crew. A sailor of the oceans and seas who demonstrates selfless dedication and loyalty, putting the crew, the ship and the mission above his/her self interests. Depending heavily...