APPENDIX  I GLOSSARY ABEAM—Bearing 90° or 270° relative from own ship. ACP—Allied  Communications  Publication. CELESTIAL  NAVIGATION—Navigation with the aid of celestial bodies. CLASSIFICATION —The determination that official information requires, in the interest of national security, a specific degree of protection against  unauthorized  disclosure,  coupled  with  a designation  signifying  that  such  a  determination has been made. CODRESS —Message having the address buried in the encrypted text. COMMISSION  PENNANT—A     long,     narrow, starred  and  striped  pennant  flown  aboard  a commissioned  ship. CONVOY—A number of merchant ships or naval auxiliaries, or both, usually escorted by warships and/or aircraft, or a single merchant ship or naval auxiliary  under  surface  escort,  assembled  and organized for the purpose of passage together. DAYSHAPES —Shapes specified in both International and Inland Rules of the Road to visually   indicate   particular   operations   or situations from one vessel to another. DEBARKATION   STATION—The place on a ship where personnel assemble to debark in boats. DECLASSIFICATION —The determination that in the  interest  of  national  security,  some  classified material   no   longer   requires   any   degree   of protection    against    unauthorized    disclosure, coupled  with  removal  or  cancellation  of  the classification  designation. DEFENSE  MAPPING  AGENCY—Government agency that produces and sells navigational charts and  publications. ENCODE—To  convert  plain  text  into  unintelligible language, usually word by word, by means of a code  book FATHOM—A unit of length equal to 6 feet. FLAGHOIST—A nondirectional means of transmitting signals with predetermined meanings taken from authorized publications. The U.S. and Allied Navies use 68 different flags/pennants or combinations   thereof   for   this   purpose. International use consists of 40 different flags and pennants. FLASHING  LIGHT—The   term   applied   to   the transmission  of  signals  by  light.  The  equipment employed may be directional or nondirectional in operation. The use of directional flashing light reduces the possibility of its interseption, thus providing   some   security.   When   security   is required at night, only highly directional flashing light should be used and its brilliancy should be the  minimum  necessary  to  provide  communica- tion.   Nondirectional   flashing   light   permits simultaneous transmission to a number of stations in  any  direction  but  has  little  security  from interception,  particularly  at  night. FORETRUCK —The  highest  point  of  the  forward mast. FORMATION—Any ordered arrangement of two or more ships or aircraft proceeding together. FUSELAGE—The body of an airplane. GAFF—A small spar abaft the mainmast from which the national ensign is flown when the ship is underway. GIVE-WAY   VESSEL—As directed by Rules of the Road, any vessel required to keep out of the way of another vessel. GNOMONIC PROJECTION—A map projection in which  points  on  the  surface  of  a  sphere  or spheroid,  such  as  Earth,  are  conceived  as  projected by radials from the center to a tangent plane. GREENWICH  MEAN  TIME—Local mean time at the Greenwich meridian; the arc of the celestial equator, or the angle at the celestial pole, between the  lower  branch  of  the  Greenwich  celestial meridian and the hour circle of the mean sun, measured westward from the lower branch of the Greenwich  celestial  meridian  through  24  hours; AI-1