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NAUI Scuba Diver 32 Diving Equipment most convenient method of keeping track of your dive time as well as your depth. The dive computer combines your depth gauge, timing device, and sometimes your submersible pressure gauge in one unit. New dive computers are introduced every year, with more features available. At a minimum, a typical dive computer records or displays the following information: • Maximum depth • Current depth • Actual dive time • Remaining allowable dive time Between dives, the computer can display information from your previous dives as well as the amount of time that you have been out of the water. The computer can also help you plan your next dive by telling you how long you can stay at different depths. See Chapter 5 for detailed information about dive computers. Backup Instrumentation Even the best instruments can sometimes fail or malfunction. Having an instrument fail does not necessarily mean an emergency, but it can end your diving day unless you have a backup. If you use a bottom timer, you should back it up with a watch. If you use a dive computer, you should back it up with a second computer or a watch and a depth gauge. If you use an air-integrated computer, you should back it up with a submersible pressure gauge, depth gauge, and watch. Maintenance Rinse your instruments in clean, fresh water at the end of each diving day and have your instruments inspected and serviced once per year by a qualified repair technician. Instruments are highly reliable, but they can go out of calibration. Also, O-ring seals can wear out and must be replaced or water can flood the instrument. If salt water gets into an instrument and stays inside, the instruments are quickly ruined. Do not subject watches to extreme changes in temperature, such as by wearing them in a hot shower following a cold-water dive. The extreme change in temperature can cause condensation in the dive watch and ruin the mechanism. It is also possible to ruin the seals in a watch in this way, which will cause the watch to flood. Verify What You Have Learned Review the following questions about instrumentation: 13. A __________________ calculates your remaining allowable bottom time while diving. 14. A diving watch must be ______________ and measure _________________ while under water. 15. Proper maintenance of instruments includes _________________________ and _________________________. BUOYANCY COMPENSATOR A buoyancy compensator (BC), enables you to control whether you float on the surface of the water, hover in the water, or sink to the bottom. You control this by adding air to or venting air from your BC. By controlling the amount of air in your BC, you can precisely control your buoyancy. Buoyancy control is one of the most important skills you will learn as a diver. Features All BCs are made of durable material that can hold air and are designed for rugged use. Alternatively, a FIGURE 2-31. WATCHES FOR DIVING MUST BE DESIGNED TO WITHSTAND PRESSURE.


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