where persons have fallen overboard and have been saved because of the timely action of a good lookout. Also, as a Signalman, you must be familiar with the international distress signals (covered in chapter 6).  Recognition  of  ships  and  aircraft,  both  U.S.  and foreign,  is  another  important  part  of  your  duties (covered in chapter 13). You  also  have  to  know  the  different  aids  to navigation and their purposes; and naturally, as a Signalman, you must keep a sharp eye on the ships in company for signals. It sounds like a tough job, and if done correctly, it is. But remember, it is a part of your job, so apply yourself. NIGHT VISION If you were to go on night watch directly from a lighted compartment, you would be almost blind for a few minutes. As your eyes become accustomed to the weak light, your vision gradually improves. After 10 minutes you can see fairly well. After 30 minutes you reach your best night vision. This improvement of vision in dim light is called dark adaptation. DARK ADAPTATION Effective dark adaptation must be planned well in advance. Exposure to excessive glare during the day will hamper the ability of the eyes to adapt to the dark. This  effect  may  last  for  several  days  if  severe; therefore, you should wear sunglasses as much as possible in the daylight. Dark adaptation before going on watch consists of spending at least 30 minutes in darkness or with the eyes protected by red goggles. Wearing red goggles is effective because red light does not affect the eyes. To complete  adaptation  for  a  night  watch,  spend  5 minutes on deck before relieving the watch. These 5 minutes allow your eyes to adjust to the amount of illumination in which they will work. Once you have your night vision, be careful that you do not ruin the effect by looking into a white light. If you have to record a message or make a log entry, always use a light with a red lens. Dim red light does not spoil your night vision. Lookout  duties,  and  reporting  procedures  are discussed  in  the  training  manuals  Basic  Military Requirements  and Lookout Training Handbook. LOGS AND FILES LEARNING OBJECTIVE: Explain procedures for  maintaining  the  visual  communications  log, the visual station file, and the watch-to-watch inventory. Naval  Telecommunications  Procedures  Fleet Communications, NTP 4, requires that an accurate and complete record be maintained of all events that occur during  each  watch.  Included  in  these  records  are  visual logs, visual station files, and publications custody logs for   the   purpose   of   maintaining   accurate watch-to-watch  publication  inventories. VISUAL COMMUNICATIONS LOG The visual communications log is maintained in a ledger-type record book or other bound book printed for  that  purpose.  The  visual  log  will  contain  a complete,  accurate,  and  chronological  record  of  all visual  traffic  except  operator-to-operator  ZWC  and service messages that do not contain the prosign BT sent and received by the command. The  visual  log  is  to  be  safeguarded  and  maintained by the watch supervisor when the visual watch is set, and by the duty Signalman or person qualified as the duty Signalman when the visual watch is not set. Before assigning any security classification to the visual log, consult OPNAVINST 5510.1. The   visual   log   is   retained   and   disposed   of according to the SECNAVINST 5212.5 (Disposal of Navy and Marine Corps Records). At the minimum, the visual log must be retained for 1 month. However, the visual log may be disposed of when the ship is decommissioned  provided  the  log  does  not  meet  any of the special criteria specified in SECNAVINST 5212.5. Visual Log Guidelines The guidelines for the visual log entries are based upon usages. The following guidelines do not cover every  situation.  For  situations  not  covered,  good judgment by the watch supervisor or duty Signalman should  suffice. Use black ink and print legibly. Leave no blank spaces between lines. 8-5