1. 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

2. PADI Final Review

3. 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)

4. Water Pressure and Air volume

5. Depth, Pressure and air Density

6. Depth, Pressure and Surface Equivalent

7. 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

8. 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

9. 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

10. 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

11. 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

12. 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)

13. 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

14. 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

15. 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

16. 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

17. 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

18. 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

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

20. 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

21. 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

22. 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

23. Wet Suits

24. Dry Suits

25. 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

26. 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

27. 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

28. 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

29. 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

30. Buddy System

31. Buddy System

32. 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

33. 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

34. Diving in Current

35. 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

36. Marine Life

37. Shark Feeding

38. 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

39. Lion Fish

40. Portuguese Man o war

41. Fire Coral

42. Stone Fish

43. Sea Urchin

44. Dive Flags

45. 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 meters/ feet away

46. 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

47. 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

48. 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.

49. 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

50. 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)

51. 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

52. 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

53. 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

54. 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 ft
Driving to altitude (going to mountains) would follow same procedures as flying

55. 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

56. 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