From 7c66201b5ae92ab9ca73a0abdbf687d17c3a94e8 Mon Sep 17 00:00:00 2001 From: bnewbold Date: Mon, 19 Oct 2009 04:49:47 +0000 Subject: fixy --- tmp/SCUBA.page | 172 +++++++++++++++++++++++++++++---------------------------- 1 file changed, 89 insertions(+), 83 deletions(-) diff --git a/tmp/SCUBA.page b/tmp/SCUBA.page index 84d1345..6e15c52 100644 --- a/tmp/SCUBA.page +++ b/tmp/SCUBA.page @@ -1,83 +1,89 @@ -============ -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 +--- +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 -- cgit v1.2.3