PADI Open Water Course Course Requirements must be completed for certification Knowledge development- completed before pool Read PADI manual, complete worksheet, Video and quiz for all 5 chapters Pass PADI final exam 2 pool practice sessions 4 ocean dives, 2 per day

PADI Final Review

Water Pressure and Air Volume At Sea level the weight of the atmosphere above us exerts a pressure of 1 Atmosphere (14.7 psi) on us Water is heavier than air so it only takes 33 feet of water to equal 1 ATM of pressure At 33 feet under water you are at a pressure of 2 ATM, 1 from the atmosphere and 1 from the water above you Pressure increases by 1 ATM every 33 feet(10 meters)

Water Pressure and Air volume

Depth, Pressure and air Density

Depth, Pressure and Surface Equivalent

Increasing Pressure and Body Air Spaces Body air spaces include Lungs, inner ear, sinuses and mask and possibly teeth fillings To equalize your ears and sinuses pinch your nose and blow gently against it To equalize your mask exhale out your nose adding air to the mask If you cannot equalize stop your descent immediately, signal your buddy or instructor An unequalized air space is called a squeeze

Equalization of Air Spaces Ascend slightly until discomfort passes and try again, after you equalize descend slower and equalize more often Continuing to descend with unequalized air spaces can lead to dammage to the eardrum An unequalized mask can cause bruising around the eyes If you cannot equalize stop the dive

Equalization of Air Spaces Never attempt a forceful or extended equalization Use short gentle, frequent equalizations Never dive with a cold or allergy, congestion can block sinuses and air passages Cold medications can wear off during a dive Never use ear plugs or goggles while diving

Effects of Decreasing Pressure on Air Spaces Air pressure decreases during ascent Expanding air must exit the body This happens naturally in your ears, sinuses and mask Expanding air in your lungs is most important Normal breathing while ascending will release expanding air from your lungs Never Hold your breath While on SCUBA It can cause Lung Overexpansion

Effects of Decreasing Pressure on Air Spaces Most Important Rule in SCUBA is Always Breath Lung over expansion can happen in as little as 3 feet, a slight pressure change Anytime the regulator is not in your mouth exhale a slow steady stream of bubbles

Breathing Underwater Pressure increases with depth and decreases air volume Density of air increases as volume decreases The deeper you are the faster you use air A tank of air that lasts 1 hour at 0 feet will last ½ hour at 33 feet (10 meters)

Air in tank vs depth Depth Pressure Air Volume Air Density 0m/ 0ft 1 atm 1 X1 10m/ 33ft 2 atm 1/2 X2 20m/ 66ft 3 atm 1/3 X3 30m/ 99ft 4 atm 1/4 X4 40m/ 132ft 5 atm 1/5 X5

Buoyancy Buoyancy of an object is dependent on the weight of the object compared to the weight of the water displaced by the object Three types of Buoyancy positive, neutral and negative The Buoyancy compensator device allows us to change our buoyancy as needed

Buoyancy The weight system allows us to overcome the bodies natural Buoyancy Salt water causes more buoyancy You will be more buoyant in salt water than in fresh water You know you are properly weighted when you float at eye level with a deflated BCD and holding a normal breath

Regulator The first stage is the “hub” of your regulator and supplies air to the components Second Stage Alternate air source The SPG/computer Low-pressure inflator hose

Alternate Air Source Combines a second stage with you BCD low-pressure inflator. If necessary you may switch to it and pass your body the primary second stage from your mouth You want to place your Alterna air source in the triangle areas formed by your chin to your lower corner of your rib cage

Yoke vs. DIN valve The Yolk system hold the first stage to the cylinder with a clamp The DIN system the regulator threads into the valve https://www.scuba.com/video/23/Differences-between-Din-and-Yoke-scuba-tank-valves.html https://youtu.be/mybvNFzPeo8

Cylinder Have your cylinder visually inspected annually, scuba cylinder are drained, open and inspected internally for corrosion or other contamination/damage

Cylinder care Have your cylinder pressure tested (hydrostatic tested) every 2-5 years= Have it visually inspected annually Close and open the valve gently, don’t use excessive force Never empty the cylinder completely this will prevent moister from entering Store in standing position Keep the cylinder out of high heat

Water is 800 times denser than air which causes many differences between terrertrial and aquatic worlds Magnification- underwater everything looks 1/3 larger which causes it to look closer Color loss occurs as you go deeper, red, yellow and orange penetrate the least, Blue, green and purple penetrate the deepest Underwater sound travels 4x faster and greater distances, we cannot tell the direction it is coming from

Staying Warm Water absorbs heat 20 times faster than air, you can chill rapidly in water 86 degrees Hypothermia is a serious condition, uncontrolled shivering means end the dive and exit the water immediately An appropriate exposure suit, wet or dry suit will keep you comfortable while diving Wet suits work by absorbing water which your body heats and retaining that water so you do not have to reheat new water

Wet Suits

Dry Suits

Buddy System Number two rule in SCUBA Diving “Never Dive Alone” Buddy System- Two or more divers working together for convenience, safety and fun Plan the dive and then Dive the Plan Agree on entry and exit points, course to follow, depth and time limits, signals and communication, turn around point, who leads and who follows, separation procedures

Buddy system cont. Predive safety check- begin(BC)- with(weights) - review(releases) – and(air)- friend(final OK) Buddy separation procedures- look for no more than one minute 360 degrees on bottom then surface and reunite on the surface and descend together On deep shipwreck meet at anchor/ascent line It is Your responsibility to stay together

Running Low On/ Out of Air underwater Make a normal ascent- cylinder is not completely empty, as you ascend you get more air from your cylinder Ascend using alternate air source- Best choice when an alternate air source is available, stay close to your buddy

Running Low On/ Out of Air underwater Controlled Emergency Swimming Ascent- completely out of air and no deeper than 30 ft. Buddy is too far away. Look up and swim to the surface making an aaah sound to exhale expanding gas. All gear stays in place, control your rate of ascent Buoyant Emergency Ascent- deeper than 30 ft same procedure as emergency swimming ascent except drop your weight belt, near surface flare arms and legs to slow ascent

Problem Management Assisting Divers Unresponsive Diver at surface- establish buoyancy for both divers, check breathing and begin rescue breaths while towing, call for help from boat Unresponsive Diver underwater- make victim buoyant, hold regulator in mouth if already there, swim victim to surface, ascend at a safe rate, check breathing at surface

Buddy System

Buddy System

Problem Management Assisting Divers Free flowing regulator- hold regulator up to lips and sip air from regulator, let excess air escape, head to surface Overexertion- most common underwater problem you feel air starvation. Feels like regulator is not providing enough air If you feel air-starved and unavailable to catch your breath, stop all activities and rest, you may hold on to something for support

Water Movement Two types of water movement affect diving, waves and current The stronger the wind the larger the waves, smaller waves 1-3 feet seldom affect diving but larger waves require more experience and may prevent diving Currents are a result of waves, tides, heating and cooling water and the earths rotation Begin your dive into or against the current, when you head back the current will assist you

Diving in Current

Bottom Composition Bottom composition types-silt/mud, sand, rock, coral, vegetation Bottom composition may be multiple types at a dive site Avoiding bottom contact keeps visibility clearer and avoids hazards like cuts or scrapes Aquatic organisms may be fragile and damaged if touched Disorientation of which way is up or down when your in midwater and cant see the surface nor the bottom

Marine Life

Shark Feeding

Aquatic Animal Injuries Be familiar with hazardous organisms in the local environment Avoid wearing shiny dangling jewelry Watch where you put your hands, knees and feet, avoid bottom contact if possible Be cautious in murky water, animal may mistake a diver for prey in poor visibility Usually very pretty or very ugly organisms who do not try to escape are dangerous Most injuries caused by aquatic animals happen because they are trying to defend themselves

Lion Fish

Portuguese Man o war

Fire Coral

Stone Fish

Sea Urchin

Dive Flags

Dive flags Unless other wise stated by a law you should stay within 15 meters / 50 feet of the dive flag Passing boats should stay 30-60 meters/100-200 feet away

Contaminated Air Contaminated Air contains unintended impurities and is very rare in diving Contaminates may be harmless at the surface but toxic at depth Compressors for filling SCUBA cylinders use special filters and separators Contaminated air may smell and taste bad but sometimes can be odorless and tasteless

Decompression Sickness Secondary Factors which can affect how much nitrogen is absorbed and released by the body leading to decompression sickness include: Fatigue, cold, illness, dehydration, Injuries, Age, Poor fitness, Alcohol consumption and strenuous activity during a dive On a very cold or strenuous Dive you breath at a higher rate and absorb more Nitrogen, count the dive as if it were 10 ft deeper for additional safety

Dive Computers Use the same computer for all dives the entire day, do not change computers or turn yours off Each Diver needs their own computer, there is no “group” computer Many serious divers have more than one computer, if one fails you may continue on the other computer Ascend at the rate recommended by the computer, it may be slower than 60 ft per min.

Dive computers When your buy a computer the first step in programing it is to read the manufactures instructions Safety Stop is Done at 15 Ft for 3 minutes Safety stops and emergency decompression stops are programed into the computer follow the instructions air supply permitting Safety stops are required any time you come within 3 boxes of a black box, at a black box or to any dive to 100 Ft or greater according to the dive tables

Dive Tables and Dive computers Because of variations in people Dive Tables and Dive computers cannot guarantee that decompression sickness will never occur Dive within the limits and slowly ascend form every dive NO Stop Diving is planning your dive so that at any time you can swim directly to the surface ( no decompression Dives)

Dive computer If your dive computer fails and you don’t have a back up you should signal your buddy, ascend, make a safety stop and end the dive

Gas Narcosis Many gases including oxygen and nitrogen have an intoxicating effect under pressure Signs and symptoms include: feeling drunk or high loss of coordination slowed thinking and slowed reactions inappropriate laughter depression, false sense of security false sense of security, ignoring or disregard for safety Anxiety or panic

Gas Narcosis cont. Most divers begin to feel effects around 100 ft Being tired or dehydrated and some prescription and over the counter medications combine with narcosis to make the effects stronger Cool, Dark water and limited visibility seem to increase narcosis possibly from additional stress Diving experience seems to reduce narcosis Ascending to a shallower depth and continue the dive at a shallower depth eliminates the symptoms

Flying after Diving cont. Repetitive dives or multiday dives (diving every day for several days in a row) a minimum preflight surface interval of 18 hours is recommended Dives requiring emergency decompression stops- a minimum preflight surface interval greater than 18 hours is suggested These times are based on an airplane cabin pressure of 2000-8000 ft Driving to altitude (going to mountains) would follow same procedures as flying

Altitude Diving Diving at altitudes above 1000 ft require special procedures Some dive computers automatically adjust, some can be set up and some cannot be used at altitude Altitude Dive tables which convert your actual depth to a theoretical depth that adjusts the pressure difference

Your Limits as a Diver Open water divers are trained to a maximum depth of 60 ft or the actual depth you reached on training dives The absolute maximum for recreational divers is 130 ft You are certified to dive in conditions as good as or better than the conditions you were trained in