NAUI Master Scuba Diver 230 Diving Techniques and Deeper Diving LEARNING GOALS In this chapter, you will: 1. Be introduced to the terms shown in bold letters. 2. Learn some equipment modifications that can be made to improve efficiency. 3. Learn why overweighting is dangerous. 4. Read about five personal limitation considerations in deep diving. 5. Learn the steps required for planning a deep dive. 6. Read about cylinder, valve, and regulator options for deep diving. 7. Learn gas management procedures for deep diving. 8. Learn four potential hazards in deep diving. COMMUNICATIONS The more advanced your diving skills become and the more time you spend under water, the more sophisticated you need your underwater communication skills to be. The most fundamental of these skills relies on the use of hand signals. Take the time to become proficient at hand signaling, and you will increase your fun and enjoyment of diving. You and your buddy may enjoy developing your own special signals, as well. Many divers use signals for indicating various forms of marine life. You use a different set of signals when you communicate by feel rather than by sight. Tactile signals are utilized during line work or when in physical contact with your buddy. You may be using a buddy line in low visibility, using a line in a search and recovery exercise, holding hands, or simply touching. The number of times the signal is repeated is the key to its meaning. Signals should be discussed before every dive. A common set of line-pull signals is: 1 pull = “Are you all right?” or “I am all right” 2 pulls = “Going down” or “Give me slack” 3 pulls = “Take up my slack” 4 pulls = “Come up” or “Haul me up” Continuous pulls = “I am being eaten by a giant squid” At times, you will need to send or receive audible messages. Some commercial dive boats use an underwater recall system that sounds like a siren. It is used in case of an emergency or when re-positioning the boat. This sound requires that you immediately surface (at the appropriate rate and with the appropriate safety stop) for further instructions. The divemaster or crew will tell or signal you whether to hold your present position or return to the boat. If there is not a recall system, apply the same rules as in the tactile system, e.g., one sharp hand clap or rap with your knife against your cylinder translates to stop, two indicates go, and so forth. Your buoyancy compensator should have a whistle attached for use on the surface. Do not blow it unless you are in distress. A whistle can be heard much more clearly than your voice, and the lifeguard or divemaster on duty will respond when it is blown. Just as with tactile signals, five blasts on your whistle means to come quickly, or help! The whistle can be difficult to use with very cold hands and lips. Written communication allows more complex information exchanges. An underwater slate and a pencil can fully convey messages too complicated for hand signals. A slate in your B.C. pocket ensures your ability to make yourself understood. Dive Flags Flags are employed when other types of signaling are impractical (figure 10-1). Divers towing floats and boats use three different types of flags: • Red/white—This is considered the sport diver flag. It is recognized internationally and it indicates there are divers in the area and to stay clear for a 30 m (100 ft) radius. • Blue/white swallowtail—This is an international code flag for the letter “A.” It indicates the boat is unable to maneuver due to a diving operation underway and to stay clear. • Blue/white (square)—This is an international code flag for the letter “P.” It is used as a diver recall. Divers leaving the immediate vicinity of their boat and those diving from the shore are vulnerable to injury by boat traffic. Under these conditions, use a diver flag
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