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:


 * 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:
 * 1) rinse thoroughly with fresh water after each use (even in swimming pool)
 * 2) keep out of direct sunlight
 * 3) 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:
 * 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:
 * 1) Inspect tank o-ring
 * 2) Clear valve with short burst (dust/water)
 * 3) Check air quality with short burst (smell - should be oderless)

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

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

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

Other:
 * 1) Mask defog
 * 2) Snorkel on left, regulator on right
 * 3) Inflate BCD before entering water
 * 4) Adjust weight belts (in water)

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

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)

http://i.imgur.com/rJRnitz.png

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.

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

 * 1) Make a normal ascent
 * 2) Ascend using an alternate air source
 * 3) Ascend using a controlled emergency swimming ascent
 * 4) 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

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

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
HowTo Videos:
 * PADI Divemaster Skill Circuit - Courtesy of UDC - YouTube - http://www.youtube.com/watch?v=AKHUqMefeg8

Easy: (most at surface)
 * Inflate/deflate BCD
 * Read and manage air with SPG
 * Properly don and adjust mask, fins, snorkel, BCD, weights
 * Ascend slowly (never faster than bubbles) and safely (hand up, looking around)
 * Pre-dive safety check
 * Pre-dive planning
 * Deep water entry (controlled seated entry/giant stride/roll backwards)
 * Clear snorkel
 * Adjust weights
 * Snorkel / regulator exchange
 * Boat diving procedures

Medium: (most under water)
 * Equipment assembly / disassembly
 * Clear regulator (exhale/purge)
 * Recover regulator hose (arm sweep/reach)
 * Clear mask (look up/purge)
 * Use alternate air source from other diver
 * Hand signals
 * Quick release weights
 * Orally inflate BCD
 * 3 min safety stop at 15 feet

Hard:
 * Establish neutral buoyancy (fin pivot)
 * Maintain neutral buoyancy (vertical) and horizontal direction
 * Mask removal, clear and recovery
 * Breathing without mask
 * Leaking inflation hose
 * Sipping from free flowing regulator
 * Emergency procedures (low air, emergency ascent, first aid)
 * Controlled emergency ascents
 * No mask swimming
 * Complete scuba gear removal, adjust and replace on surface
 * Dive tables and eRDP

Skin Diving:
 * Hyperventilation skin diving
 * Dive Headfirst skin diving from surface
 * Clear and breathe from snorkel upon ascent

Open Water Diver Manual Summaries
See Scuba/Open Water Diver Manual