Scuba Notes – Online Classwork
The SSI Diamond
- K – knowledge
- S – Skill
- E – Equipment
- E – Experience
The Six Scuba Systems
- Snorkeling System
- Exposure System
- Delivery System
- Information System
- Buoyancy System
- Accessory System
Boyle’s Law – As pressure increases, volume decreases
P1xV1 = P2xV2
1 Bar = 14.5038 PSI
10 Meters down will increase pressure 1 bar
10 meters is roughly 33 feet (32.8084)
Absolute Pressure includes the current air pressure at sea level plus depth pressure (rarely used)
Methods to deal with Ear Squeeze
- Yawning
- Swallowing
- Jaw Rotating
- Valsalva Method
One of the body’s methods of Temperature resolution is Blood Shunting, where circulation to the outer extremities is slowed.
A diver at 1 bar (2 bar absolute) will use 2x as much air as normal. At 4 bar (5 bar absolute) that would be 5x amount of air.
Normal divers use 6 to 12 liters, new divers use 12 to 15 liters
A 12 liter cylinder at 200 bar is 15 liters for 160 minutes.
Standard fill is 150 to 300 bar. First stage reduces pressure to 10 bar (145 psi). The second stage reduces to ambient presure.
Proper positioning will assist in breathing. The recommended position is at 15 to 20 degrees above horizontal
O2 in air is about 21%, Nitro is about 78%
Bottle Label Identification
DOT (Alloy Type generally 3AL{alum} steel would be something else) PSI (3000 or something else) Serial number (manufacturer) Inspection date and size (80 cubic ft or some other size)
This is only for the US, no real regulation outside the country
Dive Computers, common features
- Planning Mode
- Dive Mode
- Logbook Mode
- Alarms
- Time to Fly and Diving at Altitude
- Personal Computer integration
Analog Instruments
- Submersible Pressure Gauge (SPG)
- Depth Gauge (Digital are more accurate than analog)
- Timing Device
- Compass
MySSI Logbook
These days can be paper or digital
Buoyancy
Archimedes’ Principle – And object floating or immersed in a liquid will be buoyed up by a force equal to the weight of the volume of the liquid displaced.
Three types of buoyancy
- Positive
- Negative
- Neutral
The BC – Buoyancy Compensator is the “vest” that is the main component of the buoyancy system
The BC should be serviced on an annual basis
SCUBA Assembly
- Pre-soak the BC Strap to prevent the cylinder from coming loose (not part of current class)
- Face Cylinder valve away from you
- Place your BC at the proper height on the cylinder
- Secure BC to cylinder
- Check and inspect the cylinder o-ring or DIN fitting o-ring
- Standing behind the cylinder, position your Delivery System with the primary regulator over the right side of the information System on the left side and gently tighten
- Before turning on the breathing gas, check the primary regulator and alternate air source by inhaling gently, you should not be able to Breathe
- Attach the power inflator hose to your BC
- Face your Information System down and away from you and close to the cylinder
- Open the cylinder valve, gently seating it in the fully opened position
- Inflate your BC Fully, check function of the pressure relief and dump valves. leave your BC fully inflated and monitor for possible leakage and release air after successful leak test
- Check the performance of your regulators and the quality of breathing gas by pressing the purge valve. Clean breathing gas is colorless, odorless, and tasteless. If the gas has any taste or smell, do not use.
- Once complete, place your Delivery and Information systems incyd your BC and secure it by laying the unit down.
- For disassembling, simply revers the order. once the gas is off, it is necessary to purge all the gas from the system.
Accessory system
- Dive Light
- Dive Bag
- (Camera – not mentioned)
- (Dive Knife – not mentioned)
- Spare Items aka “Save-a-dive” kit
- Extra Mask
- O-Rings
- Extra strap
- Anti-Fog
- Lens Cleaner
- Extra Mouthpieces
- Wire Ties
- Batteries
- Light Bulbs
- Multi-purpose tool
Basic Rules of Scuba
- Breathe Continuously
- Ascend slowly and maintain control
- No faster than 9 meters per minute (30 ft per minute)
- Never dive alone or beyond your level of training
Pressure Injuries
Lung Structure
- 300 million Alveoli at the end of Bronchiole trees
- Total lung volume is only about 5 or 6 liters
- Pulmonary Veins pull blood from lungs to the heart. Only veins with Oxygenated blood
- Left side of heart to right side of heart
If at 30 meters (100 ft) with 3 bars pressure (4 bars absolute), you fill your lungs and ascend to the surface 0 bars (1 bar absolute). The gas in your lungs would expand to a volume of 20 liters. 4 times the normal lung volume.
If lungs at max inflation, it only takes 1.2 meters (4 ft) of pressure decrease to cause a tear. Lungs only withstand over pressure of 0.12 bar (0.1 in sea water) bar per meter is 0.12 = 1.2 meter or 4 ft)
Arterial Gas Embolism (AGE)
When a rupture occurs and a gas bubble is allowed into the blood stream from the lungs through the heart to the brain and causes and embolism. Causing Hypoxia and may be irreversibly damaged after 4 to 5 minutes
Pneumothorax
Air between the lungs and the lung sac that can cause pressure on the heart
Subcutaneous Emphysema
Air escapes the lungs into the area of the heart (Mediastinum) and moves up along the windpipe (trachea) into the region around the collar bone (supraclavicular region) and neck
Mediastinal Emphysema
Same as above but instead of moving up the neck, just creating pressure on the heart.
Sometimes divers would be unaware of symptoms of over expansion other than a pulling sensation from chest
Onset of symptoms is immediate and the condition deteriorates quickly
- Unconsciousness or coma
- Respiratory and circulatory distress and/or failure
- Loss of small motor and gross motor control and paralysis
- Headache
- Vertigo
- Visual, auditory, and speech abnormalities
Decompression Sickness
Caissons Disease (Paul Bert – French Physiologist)
Breathing gas under pressure causes large quantities of Nitrogen into the body. The nitrogen stays in solution as long as the pressure is maintained. If a diver ascends too quickly, suddenly reducing the pressure, nitrogen will come put of the solution and may form bubbles in the tissues and blood stream. The bubbles are called “Free-phase gas”
Dalton’s Law – The total pressure of a mixture of gases equals the sum of the partial pressures (i.e. at surface 0.68 nitro / 0.32 o2 || at 1 bar 1.36 nitro / 064 o2)
Henry’s Law – the amount of nitrogen absorbed is directly proportional to the partial pressure of the gas. In other words, as pressure increases, more absorption takes place at an equivalent rate.
Diffusion – Gas moving from an area of higher concentration to lower concentration
Perfusion – the body’s process of delivering blood to the capillary beds in the tissue.
Adipose tissue is special connective tissue that functions as the major storage site for fat. Fat has a large capacity for absorbing nitrogen, but adipose tissue is not well perfused.
Rapid ascent can cause the pressure difference to become too large and the nitrogen will come out of the solution in the form of free gas bubbles in the tissues and bloodstream, resulting in various tissue damage.
Haldane’s Critical Ratio – Discovered the body can withstand a certain level of supersaturation. This level was a ratio of about 2:1 pressure difference. A diver can spend as long as they want at 10 meters (2 bar absolute) become fully saturated with nitrogen and return to the surface with no ill effects. If the diver goes deeper than 10 meters, it is possible to absorb an amount of nitrogen that will exceed 2:1 ratio on return to the surface. The deeper they go, the faster the 2:1 ratio is reached.
Workman’s Critical Difference – Revised Haldane’s ratio to 1.58:1. Determined by multiplying the absolute pressure at 10 meters times the partial pressure by a sample at sea level. (2 bar x 0.79 ppN2 = 1.58 bar ppN2)
This determined the maximum amount of nitrogen that any tissue could contain upon surfacing, calling this the “m-value”. It was also discovered this was not the same at all depths. Fomred the basis of the Critical Difference method
Signs and symptoms
- Deep, persistent pain. Mostly in joints.
- itchy skin rash
- visual disturbances
- motor paralysis
- Weakness
- loss of manual dexterity
- vertigo
- numbness
- respiratory distress
- headache
- uncionsciousness
- loss of memory
- Nausea
Prevention
- Plan your dive and dive your plan, do not dive beyond your training
- Be aware, constantly observe your computer for depth, remaining time, remaining gas, slow ascents and safety stops
- 5 meters {16.4 ft} for 3 to 5 minutes
- Get Ready – Physically prepare for dive and be well rested and hydrated
- Be honest – evaluate your physical condition
- Get Rest – no heavy exercise 6 hours before dive
- Stay Warm – do not become overly cold during dives as this can impact circulation
Treatment
Only determined by medical professional. Most cases, recompression.
If immediate medical attention not available, follow the following steps
- Activate EMS
- Treat for Shock
- Administer Oxygen if trained and available
- Apply CPR if trained and necessary
NEVER take a diver back underwater
ALWAYS have an emergency plan before you dive
Other factors affecting Nitrogen Absorption and Decompression sickness
- Sickness
- Age
- Alcohol or Drug use
- Extreme heat or cold
- Old injuries
- Proneness to blood clotting
- Obesity
- Medication
- Lack of Sleep Extreme fatigue
- Dehydration
If these are a factor, consult doctor before diving
Avoid flying for 24 hours. Increase this amount for in the case of consecutive dive days
Nitrogen Narcosis
Referred to as “the Rapture of the Deep”.
Signs and Symptoms (anesthetic style effect more that feeling euphoria)
- Light headedness
- Unusual behavior
- Loss of dexterity
- Dizziness
- Abnormal vision and hearing
- Inability to reason or follow a dive plan
- Carelessness ab out personal well-being
- Short-term memory loss and losing track of time
Factors that increase risk
- Consumption of alcohol and/or drugs
- Fatigue
- Carbon dioxide build-up
- Anxiety
- Inexperience
Prevention – Dives below 18 meters (60 feet) should only be made with more training and experience
Treatment – Ascend to a shallower depth
Oxygen Toxicity
Happens if the partial pressure of Oxygen approaches 1.6 bar (roughly 23 psi). The theoretical depth limit for air is 65 meters, far deeper than the depth limit for recreational diving.The theoretical depth limit on pure oxygen is 6 meters (1.6). SSI recommends not exceeding 1.4 bars.
Signs and Symptoms – recognized with the acronym (ConVENTID)
- Convulsions
- Visual problems
- Ear disorder
- Nausea
- Twitching
- Irritability
- Dizziness
Prevention
- Never dive with pure oxygen as your main gas
- Always analyze the content of your tank when you are diving with a gas other than air
- Never exceed a max of ppO2 of 1.4 bar
Treatment
Lower oxygen pressure. There is no residual or lasting damage.
Carbon Dioxide Buildup (Hypercapnia)
Signs and Symptoms
- Distress and anxiety
- Headache, caused by dilation of capillaries in the brain
- Possible confusion and irrational behaviour
- Drowsiness and unconsciousness
Prevention
- Breathe Continuously
- Wearing a Total Diving System that is well maintained
- Stay within diving limit of 30 meters
- Always maintain neutral buoyancy to minimize exertion
- If you are over exerting, stop. Surface carefully if not able to catch breath
Treatment
- Provide fresh uncontaminated gas
- Administer oxygen if qualified
- Administer CPR if required and qualified
- Contact EMS if needed
Carbon Monoxide Poisoning
Possibly not observed at depth due to the increased partial pressure
Signs and Symptoms
- Red Lips and nail beds
- Headache
- Dizziness
- Nausea
- Weakness
- Uncoordinated Movements
- Confusion and inability to reason
- Unconsciousness
- Respiratory failure
Causes
- Contamination of breathing medium caused by compressor too close to exhaust of a boat or overheating of compressor (causing internal lubricants to burn and foul gas)
Treatment
- move victim into fresh, uncontaminated air
- Administer oxygen if qualified
- Administer CPR if needed and qualified
- Contact EMS
Dive Buddy
3 Reasons to have a Dive Buddy
- Provides a 2nd Total Dive System
- Psychological Well being
- Comfort of someone to assist underwater
Dive Computer
We must track the amount of dissolved nitrogen in our bloodstream and tissues throughout the diving day and week.
Guidelines to follow when planning a dive with a dive computer
- Always have your own dive computer
- Check the battery prior to the dive
- Adhere to the limits of the dive computer
- Follow the ascent display or audible warning to stay within the proper ascent rate for the dive computer
- Remain with your limits and be conservative
- Plan and execute your dive carefully, and have a contingency plan if your dive computer fails.
The most essential reason to plan dives is to prevent incidents
Proper terminology in Dive Planning
- Depth – The deepest point reached during the dive
- Bottom Time – the amount of elapsed time from the start of your descent until the start of your ascent
- Total Dive Time – The total amount of elapsed time from the start of your descent until you reach the surface including ascent and decompression stop time.
- Surface Interval – The amount of time the divers stays out of the water or on the surface between dives. Beginning as soon as the divers surfaces and and ending at the start of the next descent.
- Repetitive Dive – Any dive started more than 10 minutes and less than 12 hours after a previous dive
- No-Decompression Limits – The maximum allowed time at depth without having to perform a mandatory decompression stop during the assent.
- No-Decompression Dive – Any dive made to a depth and time that allow a direct ascent to the surface without mandatory decompression stops.
- Residual Nitrogen – The amount of excess nitrogen dissolved in our bloodstream and tissues after a dive and all previous dives in a series
- Decompression Dive: any dive which exceeds the No-Decompression Limits at a certain depth, so that a direct ascent to the surface is not possible and mandatory decompression stops must be made.
Pre-Dive Briefing
- Objective of the dive
- Conditions of the dive
- Dive Plan
- Communication
- Buddy Check list
- Equipment Familiarization
- Entry and Exit procedure
- Lost Buddy procedure
- Emergency procedure
- G/No-Go Diving Decision
Shore diving
- Check surf conditions
- Currents
- Distance to diving area from the beach
- Depth of the diving area and bottom composition
- Water Temp – Surface and at depth
- Visibility
- Accessibility from the beach
- Compass headings
- Special hazards (boat access, surfers, marine life, etc)
- Fish and Game regulations and other misc concerns
Surf entry technique
- Hold hand with buddy, use other hand to hold mask
- You and buddy will look over your inside shoulders and begin shuffling backward, maintaining contact
- Time your entry into surf to coincide with a lull between wave sets.
Calculating Gas Consumption – Factors to be considered
- Your depth
- Your gas consumption based on your level of experience
- Your breathing pattern
- The amount of work performed
SAC – Surface Air Consumption
SAC = AC x V/ (t x P)
Surface Air Consumption equals gas consumption in bar times volume of the cylinder divided by time and absolute pressure at depth
SAC = 150 bar used x 12 liter cylinder Volume / (40 minutes x 3 bar) = 15 liters/min
Basic algebra will make is so you can figure out anything else
Note that the consumption rate is variable based on experience, if you are cold, under extra weight or the work being performed.
The Ocean
- Source of life
- Source of Oxygen (85% of oxygen in air is from marine plants)
- Source of fresh water
- Swim neutral buoyant
- secure equipment
- be responsible
Marine life
The Coral Reef
Hard Corals
- Elkhorn – Large quantity, sharp and can easily cut
- Staghorn – Similar to Elkhorn but more cylindrical
- Brain
- Star – cling closely to rocks in floral bursts
- Fire – upward plumes of “flame” and because it can inflict a burning sting if you touch the nematocysts
- Lettuce Leaf – a hard coral that gives the illusion of being soft
Soft Corals
- Gorgonian
- Black and Red
Worms
- Segmented worms (tube worms)
- Feather duster
- Christmas Tree
Mollusks
- Snails
- Abalone
- Conch
- Clam
- Oyster
- Mussel
- Scallop
Cephalopods
- Squid
- Octopus
- Chambered Nautilus
Crustaceans
- Lobster
- Crab
- Shrimp
Echinoderms
- Sea Stars
- Brittle Stars
- Sea Urchins
- Sand Dollars
- Sea Cucumbers
Vertebrates
- Fish
- Mammals
Fish identification
- Dorsal Fin
- Tail Fin
- Anal Fin
- Ventral Fin
- Pectoral Fin
- Lateral Line
Potentially harmful fish
- Sculpin or “Scorpion Fish” and the Stone Fish (Sting if touched)
- Lionfish (Sting)
- Eel (biting)
- Coelenterata or Jellyfish / Man-of-War.
- Cone Shell and Sea Urchin
- The Ray (sting ray)
- Sharks (Not as dangerous as made out to be)
- Barracuda (not as dangerous as made out to be)
Things divers do to cause injury
- The diver’s negligence
- The diver’s ignorance
- The diver’s aggressive behavior
3 Things to do to protect yourself
- Swim Neutrally buoyant at all times
- Keep your equipment secured
- Always be responsible
Freshwater Environment
- Lakes
- Ponds
- Quarries
- Mines
- Marine Parks
Freshwater life
- Freshwater eel
- bass
- pike
- catfish
- Trout
- Carp
- Walleye
The Scuba Diving Experience
Taking Care of yourself
- No drinking day before dive (or during)
- Drink water
- Eat a non-gaseous breakfast and throughout the day
Avoiding Panic
Causes of Panic
- Breathing difficulty – Low or out of gas / ineffective breathing pattern
- Environmental Conditions
- Water movement
- limited visability
- underwater drop-offs
- entanglement
- hazardous marine life
- cold
- Claustrophobia
- Separation from buddy
- Equipment
- Unfamiliar
- doesn’t fit well
- perform inadequately
- Comfort and Ability
- Diving outside ability can lead to stress
Recognizing a panicked diver
- Erratic, uncoordinated movements
- Wide-eyed, fearful look
- Erratic breathing pattern with bubbles seemingly exploding from second stage mouthpiece
- Vertical originated in the water, kicks ineffective
- Flailing arms, trying to “climb” out of the water
- Difficulty obtaining positive buoyancy on the surface
Things that can be done
- Locate alt air source in case it is needed
- Approach buddy and look for source of problem
- Face buddy and get their attention
- If they are erratic, back off until they calm down as not trained to deal with this situation
If on the surface
- Completely fill your BC
- Calmly talk to your buddy, and from a distance have bubby establish positive buoyancy
- If required, approach buddy and ditch their weights and inflate their BC
- Help find a position for them where breathing is most comfortable
- If they grab you, dive below the water as they will likely let go of you
- Never needlessly endanger yourself
To prevent panic in yourself
- Respond properly “3-R Rule”
- Regain Control
- Respond
- React
- Take specialty training for the type of dive your are going to take
- Most divers in bad situations due to breaking rules
- or doing something they were not trained for
- Honestly evaluate your diving limitations and never feel pressured
- Properly maintain your Total Diving System
- Introduce only one new variable at a time
3 Rules on Scuba to 4 rules
- Breath continuously
- Ascend Slowly and maintain control
- Never dive alone or beyond your limits
- Stop, Breathe, Think and Act
Decision Matrix – I am out of air and…
- Situation 1: my buddy is close enough to help
- Action: Sharing Air
- Situation 2: The surface is closer than my buddy
- Action: Emergency Swimming Ascent
- Situation 3: My buddy is lost and the water is too deep for the Emergency Swimming Ascent
- Action: Emergency Buoyant Ascent
Being a responsible diver – I pledge to:
- Dive within the limits of my ability and training
- Evaluate the conditions before every dive and make sure they fit my personal capabilities
- Be familiar with and check my equipment before and during each dive
- Respect the buddy system and its advantages
- Accept the responsibility for my own well-being on every dive
- Be environmentally conscious on each and every dive
Specialty Cards and Recognition
- 12 Dives plus 2 specialty courses – Specialty Diver Card
- 24 Dives plus 2 more specialty cards – Advanced Open Water
- 50 Dives plus Stress and Rescue course – Master Diver card
Recognition at different milestones
- Level 5 (100 dives) – Century Diver
- Level 7 (300 dives) – Silver Diver
- Level 9 (500 dives) – Gold 500 Diver
- Level 10 (1000 dives) – Platinum 1000 Diver
- Pro (5000 dives) – Platinum Pro 5000 Diver “World most elite water explorers”