By Danny Choo CC BY-SA 2.0

Snorkeling Equipment

Chose best clothing to the ocean

Retama - Foto propia，GPL

By Peter Southwood, CC BY-SA 4.0

By Alexander Z., CC BY-SA 3.0

Snorkeling Eq.

Mask, Snorkel

• Single Window
• Double Window
• Low Volume

• Dry
• Semi-Dry

Wet Suit, Gloves, Boots

• 3mm
• 5mm
   
• Jumpsuit
• 2-piece

Fins

By Emma & Michael's Excellent Adventures CC BY 2.0

• Flutter kick
• Frog kick

• Shore dive
• Boat dive

• Positive buoyancy
• Negative buoyancy

Chose Best Clothing to Ocean

Retama - Foto propia，GPL

By Peter Southwood, CC BY-SA 4.0

By Alexander Z., CC BY-SA 3.0

"Parachuting Santa Procession" by jurvetson is licensed under CC BY 2.0.

Fly under Water

BCD

buoyancy control device

BCD

Change Buoyancy

Fix all your gears

Tank holder

Weight pocket

fix more based on your needs ...

Wing

Jacket

sit / stand

lean over

• Fix gears
• Change buoyancy
• Jacket easier to stand
• Multiple outlets
• Ask any try before you buy!

Recall

Q & A

• Which outlet will be used to deflate BCD when you diving in upside down position?

Control Your Buoyancy!

 By Soljaguar - Own work, CC BY-SA 3.0

Regulators

Breathe under water

Regulators

Components

1st stage

Meters

x 2

BCD

2nd stage

Breathe From Tank

LP

HP 200 bar

Env

How to use
&

Gear up

• From HP to LP
• Open before gear up
• Closed when store
• Take care your gears!

Recall

• Easier to find
• Meters(HP), BCD(LP), 2nd x2 (LP)

Q & A

• Why special color for 2nd?
• How many tubes?

Breathe Under Water!

"P-3B Begins First Day of Science Flights" by NASA Goddard Photo and Video is licensed under CC BY 2.0.

Diving Computer

Control Your Dive in Safe

Diving Computer

• Going
• Return
• Backup
• Follow Instructor

Rule of Thirds

DATA

Depth

Azimuth

Time

Air

DATA

Depth

Azimuth

Time

Air

No Decompression Limit

• NDL
• The time you can dive in the depth
  • Without additional decompression
• Suggestion > 7

Safety Stop

• Sign Language
• Not requirement but good to do
• 5M 3min
  • 5 ~ 6M

• When
  • NDL
• How
  • < 9m / min
  • Safety Stop
    • 5m 3min
    • ...

Ascent Procedure

• When
  • NDL
• How
  • < 9M / min
  • Safety Stop

Ascent Procedure

• Read DATA from diving computer
• Ascent with controlled

Recall

• Depth, Azimuth, Time, Air

• Ascent speed

Q & A

• What are the basic DATA in computers?

• What should be watched when ascent

Control Your Dive in Safe

By Wesley waiting - Own work, CC BY-SA 4.0

Safety Under Sea

Diving Physics

Diving Physics

Colors

 1 feet = 0.3048 meter

Refraction of Light by Water

General Gas Equation

P * V = n * R * T

Boyle's law

Gay-Lussac's law

Charles's law

Dalton's law

Henry's law

Pressure & Depth

By MikeRun - Own work, CC BY-SA 4.0

Volume & Depth

12L

6L

4L

3L

1

1/2

1/3

1/4

Physics Under Water

〞

 Any object, totally or partially immersed in a fluid or liquid, is buoyed up by a force equal to the weight of the fluid displaced by the object.

Buoyancy & Depth

12L

6L

4L

3L

3Kgw

4Kgw

6Kgw

Diver's Buoyancy

Neutral

Positive

Negative

Sea

CurrentTide

Wave

• wind-generated water wave
• surface wave

By Kraaiennest - Own work, CC BY-SA 4.0

Swell

• a series of mechanical waves
• Occasionally longer than 700m

By Michel Griffon - Own work, CC BY 3.0

Current

a continuous, directed movement of seawater

Tide

• Sea level changes
• Gravitational force by moon
• Combined with sun

By This vector image was created with Inkscape-default - Own work, CC BY-SA 3.0

• Color change by water
• Chose Correct Wet Suit
• Buoyancy changed by depth

Recall

Q & A

? bar

Pressure & Depth

By MikeRun - Own work, CC BY-SA 4.0

Volume & Depth

12L

1

1/?

? L

Volume & Depth

12L

6L

4L

3L

1

1/2

1/3

1/4

• Close to the bottom

Q & A

• Where the waves have the least impact?

Safety

Under Sea

Diving Physiology

Know your body when diving

Diving Physiology

Body During Diving

Equalization

• Ear
• Sinuses
• Lung

• Mask

Equalization

Mask

Lung

Inhale your mouth
Exhale from the nose

Do not hold your breathe

Equalization

Ear

Valsalva

Frenzel

Body During Diving

Air＝78% Nitrogen + 21% Oxygen

Nitrogen Narcosis

• > 4 bar (30m)
• Feel drunk
• Loss of coordination
• Slowed thinking
• Slowed reactions
• Confusion

Ascent slowly and no need additional medical treatment

 CNS Oxygen Toxicity

• Central Nervous System(CNS)
• ppO2 > 1.6
  
• 0.21 * 2.8 (18M) = 0.59 < 1.6
• 0.6 ppO2 during 12hr
• Hyperbaric Oxygen Seizures

Rare and almost impossible for open water divers with air

But be careful when using nitrox

https://pmc.ncbi.nlm.nih.gov/articles/PMC7092644/

Hypercapnia

• CO2 retention
• Caused by overloading
• dyspnea (breathlessness)
• headache
• confusion

• Decrease loading
• need medical treatment if unconsciousness

Decompression Issues

Decompression Illness

• aka DCI
• including Decompression sickness (DCS)
• including arterial gas embolism (AGE)

DCS

• Decompression sickness
• Type I - avoid diving at least 7 days
  • Itching
  • insects crawling over the skin
  • Mottled or marbled skin
• Type II - avoid diving at least 2~4 weeks
  • Bends for joint or skeletal pain
  • Chokes for breathing problems
  • Staggers for neurological problems.

DCS

Time to onset of first symptoms

DCS

• First aid with oxygen

• Recompression Chamber (3~6 bar)

CC BY 3.0 rs

DCS

• Follow decompression schedule
• 12/18/24 hrs avoid fly after 1/multiple/decompress procedures diving
• Avoid alcohol, sleep late, drink water more
• Keep body fit and healthy

• Gas dissolve into body when decent, and release when ascent
• How to handle gas narcosis
• Follow NDL, ascent speed
• Avoid fly after diving

Recall

• Follow NDL, ascent speed
• Ascent slowly

Q & A

• How to prevent DCS?

• How to deal with Nitrogen Narcosis

Know

Your

Body When Diving

Basic Technical

Diving Plan

Diving Check

Divers' Sign Language

Diving Flags

Q & A

• How to tell others you run out of gas?

• What meaning of this sign?

Basic

Technical

Connect to tank

Din

York

General Gas Equation

P * V = n * R * T

Boyle's law

Gay-Lussac's law

Charles's law

General Gas Equation

P * V = n * R * T

Dalton's law

P       ~ n            

Dissolve in water

Henry's law

Upwelling

• involves wind-driven motion of dense
• cooler
• nutrient-rich
• replaces surface water.

CC BY-SA 1.0

Carbon monoxide poisoning

• Headache
• Dizziness
• Weakness
• Vomiting
• Chest pain
• Confusion

need medical treatment

Refraction