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diff --git a/misc/SCUBA.page b/misc/SCUBA.page deleted file mode 100644 index 6e15c52..0000000 --- a/misc/SCUBA.page +++ /dev/null @@ -1,89 +0,0 @@ ---- -format: rst -categories: -toc: no -... - -============ -SCUBA Diving -============ ---------------------------------------------- -Self Contained Underwater Breathing Apparatus ---------------------------------------------- - -SCUBA stands for "Self-Contained Underwater Breathing Apparatus". -One of the primary organization regulating recreational SCUBA diving is -PADI (the Professional Association of Diving Instructors). - -Equipment ---------- - -:BCD: The buoyancy control device is basically an inflatable live vest - that you can inflate using the regulator (or by mouth) to control - your buoyancy. Your buoyancy changes as you use up air (tank gets - lighter for same volume displaced), inhale/exhale, swim in water - of different temperature or salinity, or change depth: increased - pressure compresses any flexible air pockets, including the BCD - itself, neoprene foam, or a dry-suit. - Most BCDs have their own pressure hoses coming from the first stage - regulator that supply air. - Sometimes there is only one vent valve, which has to be at the - highest orientation or air will not vent out of the bladders. -:Tank: Most tanks are made of steel or aluminum and can store compressed - air of up to 3000psi. They are stored at pressure to prevent moisture - from leaking in. There is a valve built into the tank itself that - usually gets taken apart and repaired every two years. Tanks - can last for decades even with heavy use; they are pressure tested - for fatigue and leaks. -:Regulator: The first-stage regulator is connected to the tank and steps - the pressure down to about 250psi above the surrounding/ambient - pressure. Hoses carry air at this mid-level pressure to the second - stage regulator/mouthpiece, which steps the pressure down to - about what is in your lungs. Depending on the regulator they can - be stiff (you have to suck a bit to get air, but then it rushes - in with force) or very natural feeling (air comes very smoothly - on inhalation and doesn't press into your lungs). -:Alternate: These days almost everybody carries a second regulator mouthpiece - for emergencies. These are always on and ready to breath from, - but usually stiffer so they don't free-flow as often. -:Dive Computer: - A dive computer monitors time and depth to give you an accurate picture - of how much excess nitrogen is in a diver's bloodstream. By - continuously integrating they usually "give more time at depth" than - hand calculations using tables (which err towards safety). -:Dry Suit: A dry suit is a sealed and air tight, keeping the diver's skin dry. - Extra insulation is needed to give warmth underneath. Some dry - suits are made of compressed neoprene. - A dry suit has to be constantly adjusted with tank air just like - the BCD to maintain inflation and buoyancy. -:Wet Suit: Wet suits work on the principle of holding water against the skin: - a diver's body warms this water and stays cozy as long as water - flow is restricted enough. Even little bit too much flow through - wrist or ankle openings can be very cold. - - -Depths ------- -A PADI Open Water Diving course gives a recommended limit of 20m/60ft. -A "deep dive adventure course" gives a recommended limit of 30m/100ft, -and additional experience gives a limit of 40m/130ft. - -With careful decompression stops and enriched compressed air (higher oxygen -content) it's possible to reach depths of hundreds of meters. Sometimes -commercial divers will dive for many hours using surface supplied air, -then live at the surface in a compression chamber overnight between dives -to stay at the same pressure [*]_. - -History -------- -I'm pretty sure `Jacques Cousteau`_ invented the aqualung, which is the basis -for modern diving, but I'll have to check. - -.. _Jacques Cousteau: /k/jacquescousteau/ - -Flying ------- -After a regular no-decompression dive, wait at least 12 -hours before flying (or going to high altitude, eg over 300m). - -.. [*] Need a citation, heard this word of mouth |