spell checked and changed some permissions

1 files changed, 68 insertions, 6 deletions

diff --git a/SCUBA b/SCUBA
index be524ca..4ffe3d6 100644
--- a/SCUBA
+++ b/SCUBA
@@ -1,13 +1,60 @@
 ============

 SCUBA Diving

 ============

+--------------------------------------------

+Self Contained Underwater Breathing Apparatus

+--------------------------------------------

 

-SCUBA stands for "Self-Contained Underwater Breathing Aparatus".

-The primary organization regulating SCUBA diving is PADI (the

-Professional Association of Diving Instructors) 

+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). 

 

-Safety

-======

+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

 ------

@@ -15,7 +62,22 @@ 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.
\ No newline at end of file
+hours before flying (or going to high altitude, eg over 300m).

+

+.. [*] Need a citation, heard this word of mouth