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== Open Water Diver Manual Summaries ==

http://i.imgur.com/rbRlSWN.jpg

ISBN: 978-1-878663-16-0 (c) PADI 2010

== Underwater World ==

* Whether an object sinks, floats or does neither in water depends on its weight and is displacement.
* You'll use lead weight and a BCD, as well as lung volume, to control your buoyancy.
* The body is made up mostly of in-compressible liquid, so you only feel pressure on the air spaces, which hold compressible air.
* There's a proportional relationship between pressure, air volume and density.
* You can use one of three techniques every metre / few feet to equalize your ears to prevent a squeeze while descending.
* You exhale into your mask through your nose to prevent a squeeze.
* Never continue to descend if you can't equalize.
* The most important rule in scuba diving is to never hold your breath.
* Don't dive with a cold or allergy congestion, even with decongestant.
* The deeper you go, the faster you use up your air supply.
* When scuba diving, breathe slowly and deeply, and avoid getting out of breath.

== Dive Equipment and The Buddy System ==

* Comfort and fit are the two most important criteria in purchasing dive gear
* You can't use goggles for scuba diving because they don't enclose your nose
* You need to rinse your equipment in fresh water after each use
* The jacket BCD is by far the most common BCD used by recreational divers
* Your scuba cylinder needs an annual visual inspection, and periodic pressure (hydrostatic) testing
* You never leave scuba cylinders stating unattended - you block/secure them when transporting so they can't fall or roll.
* Regulators reduce cylinder pressure in two stages to breathing pressure
* A regulator's most important feature is ease of breathing
* You need to have your regulator professionally serviced annually
* Have the dust cap in place and don't push the purge button when you rinse your regulator
* You need an SPG (submersible pressure or contents gauge) so you can tell how much air you have at any time during the dive
* You always dive with a buddy for safety, practicality and fun
* You can make all your dive gear match and look good without sacrificing comfort, fit or important features

== Adapting to the Underwater World ==

* Objects are magnified when you see them underwater, making them look closer and/or larger
* Water absorbs light and colors
* It's hard to tell sound direction underwater
* Water absorbs heat about 20 times faster than air
* If you start to shiver continuously, get out of the water, dry off and seek warmth
* It's best to move slowly and stay relaxed underwater

== Respiration ==

* For maximum efficiency, breathe slowly and deeply
* Overexertion symptoms include fatigue, labored breathing, a feeling of suffocation, weakness, anxiety, headache, muscle cramping and a tendency to panic
* You prevent overexertion by staying relaxed and knowing your limits
* If you become overexerted, stop all activity and rest
* Airway control lets you breathe past small amounts of water

== Dive Equipment ==

* Wet suits and dry suits insulate you, but differ in that you get wet in a wet suit and stay dry in a dry suit
* You should avoid wearing an excessively tight hood
* You want to wear gloves while diving for thermal protection and to avoid cuts, scrapes and stings
* Although you're protected (to a large extent) from the environment, remember that the environment isn't protected from you - use care to avoid damaging aquatic life
* Be cautious to avoid overheating in your exposure suit
* The most important feature in a weight system is the quick release
* Locate your alternate air source in the triangle formed by your chin and the corners of your rib cage
* Look for a dive knife with both smooth and serrated edges and a sheath
* You need dive instruments to tell you depth, direction, temperature, time and air supply

== The Dive Environment ==

* Temperature, visibility, water movement, bottom composition, aquatic life and sunlight affect dive conditions
* A thermocline is an abrupt transition to colder water
* Plan your dive accounting for the water temperature at your planned depth
* When possible, use a visual reference for descending and ascending
* When diving with a current present, head into the current during the dive
* If caught in a current, don't fight it - swim across the current, or establish buoyancy and signal for assistance
* Avoid bottom contact by staying neutrally buoyant
* Most aquatic life injuries result from carelessness - watch where you put your hands, feed and knees
* Wear gloves and an exposure suit to reduce the likelihood of aquatic life stings and cuts
* Sunburn is entirely avoidable
* Surf diving requires special training and techniques
* If you get caught in a rip current swim parallel to shore until you're out of it

== Dive Planning and Boat Diving ==

* Planning your dive plans your fun
* A dive plan doesn't have to be complex, nor take a lot of time, nor be inflexible, but you do need to follow it
* Boat diving has many benefits that make it popular
* You want to inspect and pack your gear appropriately before a boat dive
* Different parts and areas on a boat have nautical terms you should know
* Be careful when moving around on a rolling boat with your gear on
* Listen to crew briefings and procedures, where to enter and exit the water, and other techniques and emergency considerations
* Don't get under another diver who's climbing the boat ladder
* You may choose to avoid seasickness by taking seasickness medication

== Problem Management ==

* Most problems occur at the surface
* You prevent most problems by staying relaxed and diving within your limits
* If you have a problem at the surface, establish positive buoyancy and call for help if you need it
* A diver with a problem who is in control tends to respond to instructions, and to establish buoyancy
* A panicked diver tends to spit out the regulator, push off the mask and to not inflate the BCD or drop weights
* When assisting another diver, establish buoyancy, calm the diver, help the diver reestablish breathing control, and if necessary help the diver back to the boat or shore
* If you watch your SPG, it's highly unlikely you'll run out of air
* You can breathe from a free-flowing regulator by not sealing your lips on the mouthpiece
* Entanglement isn't a big deal if you react calmly and carefully untangle yourself
* Bring an unresponsive diver immediately to the surface, check for breathing and pulse, and begin rescue breathing and/or CPR as necessary
* Ask for help when you need it

== Dive Accessories ==

* You use a surface float to support your dive flag, for resting and to carry accessories
* Use an appropriate dive flag when diving where boats may be present and according to local law
* Don't attach a full collecting bag to your gear
* Underwater lights have both day and night uses
* A spare-parts kit can help you keep from missing a dive
* Start and maintain a log of all your dive adventures
* To communicate with an underwater slate, you have to have one

== Health for Diving ==

* Don't drink, smoke or take drugs before diving (or ever)
* Don't dive when you don't feel well
* Stay in good health
* Have a physical examination at least every two years
* Keep tetanus and typhoid immunizations current
* Pregnant women shouldn't dive
* Review your dive skills and knowledge after a period of inactivity

== Breathing Air at Depth ==

* Air is 79 percent nitrogen and 21 percent oxygen
* Contaminated air symptoms include headaches, nausea, dizziness, unconsciousness, and cherry red lips and nail beds
* Don't have your cylinder filled with oxygen, and don't use enriched air unless certified in its use
* To avoid nitrogen narcosis, avoid deep dives
* Decompression sickness is caused by excess nitrogen forming bubbles in the body after a dive
* Stay well within dive table and dive computer limits, especially if secondary factors apply to you
* Signs and symptoms of DCS include limb and join pain, tingling, numbness, paralysis, shock, weakness, dizziness, difficulty breathing, unconsciousness and death
* Decompression illness (DCI) is a clinical term for both decompression sickness and lung over expansion injuries
* A diver with DCI should receive emergency oxygen, rescue breathing and CPR if necessary, and will require treatment in a re-compression chamber

== Dive Tables and Dive Computers ==

* Dive tables and dive computers use mathematical models to estimate the theoretical nitrogen in your body before, during and after a dive
* People vary in their susceptibility to DCS, so no computer or table can guarantee you'll never get DCS, even within its limits - so dive well within table/computer limits
* A dive computer has some use advantages and disadvantages compared to tables, but it is neither more nor less valid
* Recreational divers only make no decompression (no stop) dives
* The RDP is the most popular recreational dive table, and it is the first one developed and tested exclusively for recreational diving
* The eRDPml and dive computers offer you more no decompression dive time when making multilevel dives
* You must account for nitrogen you absorb on a dive if you make a repetitive dive before your nitrogen levels return to normal
* Stay within the depth limit of your training and/or experience - generally:
** 12 m / 40 ft - Scuba Divers
** 18 m / 60 ft - Open Water Divers
** 30 m / 100 ft - general recreational limit
** 40 m / 130 ft - maximum limit
* Be a SAFE Diver: Slowly Ascend From Every Dive

== Special Dive Table and Computer Procedures ==

* You should make a safety stop at the end of virtually all dives (except when an emergency prohibits it)
* A safety stop is a pause in your ascent between 3 and 6 meters / 10 and 20 feet for three minutes or longer
* Consider a safety stop mandatory if you dive deeper than 30 metres / 100 feet or reach any limit on the RDP or your computer
* For recreational divers, decompression is only an emergency procedure
* You need to follow special procedures when diving at an altitude greater than 300 metres / 1000 feet
* Follow the recommendations for flying after diving conservatively, and stay up to date with the most current recommendations
* Plan cold/strenuous dives with the RDP as though the depth were 4 metres / 10 feet deeper than actual - with a computer, be conservative using the most appropriate method for your computer

== Using a Dive Computer and Basic Compass Navigation ==

* You should have your own computer while diving - don't try to share one
* Keep your computer turned on all the time
* The dive medical community recommends that you make your deepest dive first and plan successive dives to progressively shallower depths
* Stay well within computer limits
* Back up your computer with dive tables
* Underwater navigation skills add to dive fun and safety
* The compass lubber line always indicates your travel direction; the compass needle always points north

== keywords ==

[[Category:Manuals]]
[[Category:Scuba]]
[[Category:Recreation]]

Scuba/Open Water Diver Manual - Revision history

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