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