Scuba/Notes

Scuba

SCUBA - self-contained underwater breathing apparatus

Originally was an acronym, but now it is just "Scuba".

Minimum age for certification:

10 years - Junior Open Water Diver / Scuba Diver
15 years - Open Water Diver / Scuba Diver

PADI - Professional Association of Diving Instructors

Rules and Tips

Number one rule to Scuba – Breath Continuously (and never hold your breath)

Always breathe slowly and deeply and continuously when using scuba. Strive to develop airway control.

Ascend (rise) less than 60 feet per minute (18 meters / minute), or 1 foot per second. Never ascend faster than your bubbles.

Equalize frequently (every few feet) to avoid squeeze / reverse squeeze (reverse block). Reverse block is rare, usually caused by medication wearing off.

Currents: Go against current at start of dive, so when you are tired you are not fighting it to get back. Currents are weaker on the bottom, so dive down to avoid currents. Avoid touching the bottom.

Average dive time – 30-40 minutes, depending on depth, physical condition, temperatures, etc.

Do not take regulator out to cough, throw up (“feeding the fish”), or on emergency ascends. Regulator is designed to clear all these.

Descend along an anchor line, or other descent line to help maintain direction and speed

Signals

Tap buddy's shoulder or rap on your cylinder to get attention

hand signal = meaning
ok = ok
stop = stop
Swipe throat = out of air
Pound chest = low on air
Two fingers to lips = share air
rock hand = something is wrong
thumb up = going up
thumb down = going down
swipe = level off
point to ear = ears not clearing
cross arms and shake = cold

page 106-107

Buddy System

PADI Rule - always dive with a buddy, who stays nearby at all times

Equipment

Mark your equipment so it is easily identifiable

Basic Equipment (Snorkel and Scuba)

When you start learning to scuba dive, as a minimum, you want your own: [1]

Mask (not goggles)
Snorkel
Fins (not flipper - Flipper is a dolphin) and boots

Scuba Diving: Necessary Gear - YouTube - https://www.youtube.com/watch?v=wCzxKGOT5B0

Scuba Equipment

When you start diving more, you will want to invest in the following, but can rent for now:

Dive watch / Underwater timepiece
Buoyancy Compensator Device (BCD) (also "control" is commonly used) (types: jacket/vest, back-inflate, backplate and wing)
Scuba Cylinder (not tank, although tank is commonly used)
Regulator (set of ‘regs’)
Submersible Pressure Gauge (SPG)
Weight system and weights
Dive Tables / Recreational Dive Planner (RDP)

Extra Recommended Scuba Equipment

Exposure suites: wet-suit / dry-suit
Dive computer (easier than RDP)
Compass
Thermometer
Slate
Equipment bag
Log book

Scuba Accessories

Surface float – flag, rest area
Dive flag
Slates – for writing
Dive light
Spare parts kits (“save a dive kit”)
Log book
Dive knife – blunt tip better, can be used as screw driver
Console – compass, depth gauge, air pressure
Timing device (watch) – water proof watch

Maintenance

All Scuba equipment:

rinse thoroughly with fresh water after each use (even in swimming pool)
keep out of direct sunlight
store in a cool, dry place

Equipment Bag

Pack in reverse order of what you will need, so that what you will need first is on top
Get a bag that won't rot easily due to water and sunlight

Save a Dive Kit

“Save a Dive Kit” – small pieces, first aid kit, etc.

o-rings
adjustable fin strap

Weights

Proper weighting – float at eye level with full breath and deflated BCD
Buckle on left, for right hand quick release
Quick release is most important feature

Mask

Some include a purge - if you have troubles clearing your mask
Proper fit - use "sniff" test. (without strap, push gently against face and inhale, should make a seal)
Use mask defog

Snorkel

Goes on left side of face (opposite of regulator)
When on surface, save on cylinder air by using snorkel
Get a "dry" snorkel if you don't like water splashing in

Fins

full foot - warm water, easy to put on, but size is set
adjustable straps - usually wear with boots (straps are prone to break)
Split fins - thrust water straight back for maximum efficiency

Regulator

Regulator: (“set of regs”)

2 stages
Stage 1 – drops 3000 psi to 150 psi
Stage 2 – drops to breathable pressure
2 second stages – primary and alternate (buddy reg)
- Brighter color
- “Octal”
- Alternate breaths harder (for emergencies)
Inflation hose – connect to BCD
Submersible Pressure Gauge (SPG)
Body right – both stage 2
Body left – SPG and BCD Inflation Hose

Components: first stage, second stage, pressure gauge, purge button, alternate air source

Connect regulator to tank facing head. Top of BCD should align with top of tank valve

Scuba Cylinder

Scuba Cylinder (tank) contains a mixture of:

Does not contain pure oxygen, otherwise would get oxygen poisoning
~80% nitrogen (79%) stored
~20% oxygen (21%) burned
Materials – Aluminum (lighter, holds less, will float) or Steel (heavier, holds more, will sink)
Fill to 3000 PSI (207bar)
Finish dives with at least 500 PSI (35bar)
Every 5 years hydro-static test – 5000 PSI test
Label of S80 means 80 cubic feet of air, 3AL means Aluminum, SS means steel, DOT mean regulated by Department of Transportation
3 Valves:
- K Valve – 80% of valves (regs clamps on)
- J Valve – older (before gauges)
- DIN Valve – for high pressure (regs screw into valve) (common in Europe)
O-ring – check
Valve Dust cap – keep on
Valve cover cap - leave off when tank needs to be filled

Scuba cylinders are technically all high-pressure gas containers, but within the industry in the US there are three nominal working pressure ratings (WP) in common use: [2]

low pressure (2400 to 2640 psi — 165 to 182 bar),
standard (3000 psi — 207 bar), and
high pressure (3300 to 3500 psi — 227 to 241 bar).

Buoyancy Compensator Device (BCD)

(also "control" is commonly used)

types: jacket/vest, back-inflate, backplate and wing
Wear a wet suit, body suit or at least a T-shirt/sweatshirt to reduce chaffing

Assemble Equipment

HowTo Videos:

SCUBA Equipment Set-up Demonstration - YouTube - https://www.youtube.com/watch?v=V2BYlSmLf_Q
How to set-up scuba diving equipment by Voceana - Exclusive Scuba Diving - YouTube - https://www.youtube.com/watch?v=7vP9adBY2LY
PADI Divemaster Skill Circuit - Courtesy of UDC - YouTube - http://www.youtube.com/watch?v=AKHUqMefeg8

Check cylinder:

Inspect tank o-ring
Clear valve with short burst (dust/water)
Check air quality with short burst (smell - should be oderless)

Attach BCD:

Wet BCD strap
Slide BCD onto standing cylinder
Turn cylinder so valve faces BCD and your head
Position top of BCD hard plate, or collar, to be even with base (or top) of cylinder valve
Secure cylinder band - tighten and lock
Check that it is secure by lifting cylinder with BCD back-plate and see if cylinder wiggles

Attach Regulator:

Inspect regulator o-ring
Clear valve with short burst (dust/water)
Remove regulator dust cap
Attach regulator to cylinder so primary 2nd stage goes to the right
Tighten to finger tight
Attach low pressure inflator (LPI) hose

Safety Check:

Slowly turn on air (counter clockwise) with SPG pointed away from face
Check for leaks
Open valve all the way, and turn back about 1/4 of a turn (in other words don't over do it)
Check SPG for expected pressure
Test Purge
Test inflate / deflate
Check easy breathing
Taste and smell air
Check for bad air (taste/smell)
Secure your hoses and gear (clips)
Lay down (with bcd/hose on top) so it does not fall over

Other:

Mask defog
Snorkel on left, regulator on right
Inflate BCD before entering water
Adjust weight belts (in water)

Pressure

Buoyancy

positive (float), neutrally, negative (sink)
Control with BCD
You are more buoyant in salt water than fresh water
Fine tune with 'fin pivot'
"I’m not fat, I’m just buoyant"

BCD – Buoyancy Compensator Device (aka “BC”) – controls buoyancy

Pressure Table

Depth	Pressure	Volume	Density	Dive Limit
0m / 0ft	1 bar/ata	x1	x1	Surface
10m / 33ft	2 bar/ata	1/2	x2	3 min Safety Stop (5m/15ft)
20m / 66ft	3 bar/ata	1/3	x3	Novice - Open Water Training (18m/60ft)
30m / 99ft	4 bar/ata	1/4	x4	Recommended Limit - Beyond Open Water Training (30m/100ft)
40m / 132ft	5 bar/ata	1/5	x5	Maximum Recreational Limit - Deep Diver Training (40m/130ft)

Dive Tables

See Scuba/Dive Tables

Plan all dives to be No decompression (no stop) diving
RDP – Recreational dive Planner
Repetitive dives – take residual nitrogen into consideration
Diving Depths:
- 30m / 100f – recommended limit
- 40m / 130f – max recreational limit
More than six hours, residual nitrogen has little consequence
Bottom time is total time in minutes from beginning of descent until beginning of final ascent

PADI dive tables include 4 parts:

how deep you are going (across the top)
how long you are going to be down (left center)
surface interval (right side)
pressure group (left side) - residual nitrogen

Which can be used to answer 3 questions:

What is my dive time limit for a desired depth?
What is my residual nitrogen for a repeat dive?
What is my maximum allowable bottom time?
What is my minimum surface interval? (use backside)

Altitude

Diving at Altitude requires adjusting the dive tables

Elevations of 300 m / 1000 feet, or higher, have special considerations
Altitude Dive Table

Flying

Single Dive - wait minimum of 12 hours Multiple Dives - wait minimum of 18 hours

Dive Profile

Dives are considered separate with at least 10 minute surface interval.

Environment

Variables of Diving

(things to consider when diving)

Temperature
Visibility (aka ‘viz’)
Currents
Bottom composition
Aquatic life
Sunlight

Thermocline

Thermocline – abrupt temperature drop in water (hot/cold layer)

Water ranges: -2° C / 28° F to 30° C / 85° F

Animal Life

Treat with respect
Carefully place feet / hands
Avoid shiny jewelry
Spearfish – remove quickly to avoid attracting predators
Exposure suits
Swim naturally buoyant
Swim carefully
Watch where you put limbs
Avoid touching

Temperatures

Ideal swimming is 80 degrees

Common water temperatures (from BSA Sae Swim Defense course)

hot tubs < 104
body temp 98.6
therapy 86-90
seniors 84-86
youth instruction 82-86
competition 79-81

ideal temperature = 80
hyperthermia > 910s
hypothermia < 70s

Planning

Determine where you are going
Determine where you will dive and the path
“Idiot check”
WBARF before diving

Decide:

entry and exit points
course to follow
time and depth limits
communications
returning air pressure
technique to stay together
what to do if seperated
emergency procedures
dive objective

Pre Dive Checklist

Weights, BCD, Air, Releases, Final OK

Mnemonic: WBARF
Mnemonic: Boys Will Run After Females
Mnemonic: Begin With Review And Friends

WET BARF - Weights - Emergency plan - Time - BCD - Air - Releases - Final OK

Problem Management

Controlled emergency ascend
- 10-12m / 30-40’
- Say ‘ahhhh’ on the way up
Buoyant emergency ascend (dangerous, last resort)
“near drowning”
Nitrogen narcosis – silly when deep, solution ascend a few feet
Decompression Sickness (DCS, aka ‘bends’)
- Safety Stop – preventative measure – at 5m / 15’ for 3-8 minutes
- Breath continuously
- Slowly ascend
- Recreational divers plan all dives as No Decompression (no stop) diving
STOP - Stop Think Observe and Plan
Need help? Ask!

Emergency Ascents

Make a normal ascent
Ascend using an alternate air source
Ascend using a controlled emergency swimming ascent
Make a buoyant emergency ascent

Safety Stop

Reduce DCI Risk

Recommended any time you dive more than 20’
Required if you dive near any limit on Dive Tables
Stop at 5m / 15ft for 3 minutes or more
Should plan for all dives, but mandatory deeper than 30m / 100ft

Advanced Equipment

Exposure Suits

Wet Suit
- http://en.wikipedia.org/wiki/Wetsuit
- “Shorty”
- “farmer john”
- full
Dry Suit – for really cold conditions

Compass

Lubber line – direction of travel
Magnetic North Needle
Bezel – two index marks
Heading reference

Misc

Boat Orientation

Bow (going ‘forward’)
Stern (going ‘aft’ or ‘rear’)
Starboard (right) (remember ‘first start on right’)
Port (left) (remember same amount of letters)
Windward side (direction wind coming from)
Leeward (direction wind leaving on)
Head (bathroom)
Galley (kitchen)
Helm / Steering well (on the bridge in the wheelhouse)

Snorkeling

Snorkeling (aka snorkel-jockeys)

Skin diving

Skills