SSI Open Water Diver Flashcards
Q: What is the SSI diamond?
A: The SSI diamond consists of four parts
- Experience
- Knowledge
- Equipment
- Skills
Q: What are the qualifications requirements for the open water diver certification?
A: Open water diver (the full qualification)
- 6 Academic session
- 6 Pool session
- 4 Open water dive
Q: what are the 6 elements of the total diving system?
A: there are 6 components
- Snorkel system
- Exposure system
- Delivery system
- Information system
- Buoyancy system
- Accessory system
Q: What are the differences in heat loss between air and water?
- water is a heat sink, air insulates
- in water you lose heat 25-30x faster
Q: What is the effects (3) of heat loss on the body while diving
- hypothermia if the core temperature drops below 35°
- when cold, the body may reduce circulation to the extremities in a process called blood shunting
- also when cold, the body can’t absorb nitrogen buildup as well
Q: describe the three types of heat loss during diving
- convection: steady flow of new water means it won’t reach equilibrium so heat loss intensifies
- internal conduction: when gas expands it cools, so breathing gas cones out cold and the body has to use energy to heat it
- external conduction: contact with water causes heat transfer
Q: Describe the most effective and efficient breathing pattern and body position for diving
- calm and continuous with a deep inhale and a long exhale
- body at a 15-20 degree angle so lungs and mouth are horizontal
Q: Why does air consumption increase with depth? Name four factors that influence air consumption rate.
- air consumption increase is due to the air coming out compressed, so more air is consumed per breath
- being cold
- excessive exertion
- improper response to stress
- poor physical condition
Q: What are air consumption rates for land versus water?
- air: 6-12 litres per min
- water: 12-15 litres per min
Q: what percentage of heat loss comes from head and extremities?
30-40%
Q: When the torso and brain get too cold, what is the bodies’ response and what is the name that response?
blood shunting: reduced circulation to extremities
Q: describe the two main types of delivery system
- open circuit demand regulator: used air gets released as bubbles
- closed circuit rebreather: used air goes into a tank and gets recycled
Q: Name the components of the delivery system and their function.
- Demand regulator
- First stage: tank pressure to 10bar
- Second stage: 10 bar to ambient
- primary secondary stage: for breathing
- secondary secondary stage: for sharing gas
- Dive cylinder: holds breathing gas
Q: name the 7 elements listed on a cylinder marking
- Safety body overseeing manufacture and safety
- Material
- Pressure rating
- Serial number
- Manufacturer
- Month + Year manufactured
- Volume (cu.ft.)
Q: what are the two valve systems for connecting regulator and cylinder
- Yoke
- DIN connection (as in DINA4)
Q: Name the components of the bouyancy system and their function.
- BC: Buoyancy compensator
- Weights: as belt or integrated pockets
- Pressure adjuster
Q: Explain the Archimedes principle and how it relates to diving
- An object submersed in liquid will displace liquid equal to its volume
- if the weight of the displaced liquid is greater than the object (lower density) it will float
- if the weight of the displaced liquid is less than the object (high density) it will sink
- if it is equal, the object stays in equilibrium
Q: Name the 3 components of the information system and their function.
- dive computer
- underwater slate and shaker
- analogue instruments
Q: What are the three most common configurations for information systems
- air integrated dive computer + compass
- regular dive computer + submersible pressure gauge + compass
- all analogue instruments
Q: What 5 analogue measurement devices are often part of the information system?
- Submersible pressure gauge
- Depth gauge
- Time piece
- Compass
- Thermometer
Q: What are the 5 functions most dive computers have?
Planning mode
- determine no-decompression time for planned dives
- see current surface interval (time till next dive)
- View above two time intervals for different depths while planning
Diving mode
- automatically activates in water
- track: depth, actual bottom time, remaining no-decompression time
- warns about ascent rate
- when back on surface, will calculate nitrogen release rate
- so if dive again, will take residual nitrogen into account
- air integrated: also tracks air and time remaining from cylinder pressure and air consumption rate
Logbook mode
- stores some dives, but can also be transferred to Logbook
Alarms
- can set alarms for various events
- ascent too fast, nearing end of no-decompression time, air low etc.
Time to fly
- how long to wait after flying
- also adjust nitrogen release rates for altitude
Q: Explain the 5 basic maintenance methods for diving gear by system.
Recorded in logbook
- Delivery System: performance tests, disassembled, cleaned, low pressure seals and dynamic o-rings are replaced
- Information System: accuracy tested and batteries checked
- Buoyancy Compensator: checked for leaks, seam integrity, buckle tension. Disassembled, cleaned and tested
- Visual Inspection: Annual inspection of cylinders to check for rust etc
- Exposure System: minor repairs or specialist maintenance
Q: What are the 14 steps in assembling SCUBA gear
Assembling SCUBA gear:
1. Pre-soak your BC strap to prevent the cylinder from becoming loose underwater.
2. Face the cylinder valve away from you.
3. Place your BC at the proper height on the cylinder by using the height adjustment strap (if available).
4. Secure your BC to the cylinder.
5. Check and inspect the cylinder o-ring or DIN fitting o-ring for cuts.
6. Standing behind the cylinder, position your Delivery System with the primary regulator over the right side and the Information System on the left side and gently tighten.
7. Before turning on the breathing gas, check the primary regulator and alternate by inhaling gently — you should not be able to breathe.
8. Attach the power inflator hose to your BC.
9. Face your Information System down and away from you and close to the cylinder.
10. Open the cylinder valve, gently seating it in the fully opened position.
11. Inflate your BC fully, check function of pressure relief and dump valves, leave your BC fully inflated and monitor for possible leakage and release air after successful leak test.
12. 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 breathing gas has any odor or taste, DO NOT DIVE WITH THAT CYLINDER! Once you have checked the quality of the breathing gas, breathe through your regulators and make sure they are working properly.
13. Once complete, place your Delivery and Information Systems inside your BC and secure it by laying the unit down.
14. For disassembling, simply reverse the order. The only difference is turning the breathing gas off. Once the breathing gas is off, it is necessary to purge all breathing gas from the Delivery System before removing from the cylinder.
Q: What are the three basic rules of SCUBA?
- Breathe continuously
- Ascend slowly and maintain control
- Never dive alone and beyond your training
Q: What is the max rate of ascent?
9m per minute
Q: In basic terms, describe the respiratory process
Oxygen from the air in the lungs diffuses into the bloodstream through the pulmonary capillaries
At the same time Carbon Dioxide diffuses out of the blood into the air to be exhaled
The oxygen rich blood flows into the left side of the heart through the pulmonary vein
It is transported through the body via the aorta, organs absorb the oxygen and diffuse Carbon Dioxide into the blood
Oxygen low blood flows into the right side of the heart and from there back into the pulmonary bed
Q: Name the three components of the lungs, what is the average lung capacity?
Bronchioles (air pipes)
Alveoli (grape like bunches)
Pulmonary capillary bed (for blood)
capacity: 5-6 litres
Q: what is the maximum amount of overpressure lungs can withstand, and how much depth does that equate to?
A: 0.12 bar or 1.2m depth
Q: give an example of how gas bubbles could enter the bloodstream
A: by lung overexpansion during ascent. if you don’t breathe normally and hold your breath while ascending, the air expands in you lungs which is dangerous. breathing normally prevents this injury
Q: List four possible lung overexpansion injuries
Arterial Gas Embolism
Pneumothorax
Subcutaneous Emphysema
Mediastinal Emphysema
Q: Describe cause, symptoms (7), prevention and treatment of Arterial Gas Embolism
cause
Arterial Gas Embolism. an embolism describes arterial blockage. this comes from air entering the bloodstream via ruptured Alveoli and traveling to the brain causing a blockage in the capillaries
signs:
unconsciousness while surfacing or withing 6min
signs similar to a stroke: slurred speech, confusion, weakness in limbs (can be both sided)
respiratory and circulatory distress or failure
loss of motor functions and paralysis
headache
vertigo
visual, auditory, speech anomalies
prevention:
do not ascend faster than 9m per minute
treatment:
the usual 4 first aud steps
Q: Describe symptoms (2) and treatment of Pneumothorax
Pneumothorax: air escapes into the lining between lungs and ribcage and pressure can cause the lungs to collapse
breathing difficulties
heart failure
Q: Describe symptoms and treatment of Subcutaneous Emphysema
Subcutaneous Emphysema: air escapes from lungs to heart region and from there into trachia (windpipe) and collarbone region
voice change
swollen neck and throat
crackling sensation when touching swollen area
breathing difficulties
Q: Describe cause, symptoms (4), prevention and treatment of Mediastinal Emphysema
Mediastinal Emphysema: air escapes from the lungs to the heart and presses on the heart.
cyanosis: blue lips and nail beds from lack of oxygen
chest pain
weakness
respiratory distress
prevention
* breathe continuously
* don’t ascend faster than 9m/min
treatment: the usual first aid 4
Q: What are the four first aid steps?
treat the shock
administer oxygen
administer CPR
get the patient to emergency treatment (shouldn’t this come first?!)
Q: Define the term partial pressure.
A: the total pressure of a gas is given by the pressure of its component parts, the pressure of these parts is called partial pressure
Q: List the percentages of nitrogen and oxygen in gas and calculate the partial pressure of each at 1 bar
Nitrogen: 79%, pp: 0.79bar
Oxygen: 21%, pp: 0.21bar
Q: Define the term gradient and relate the definition to the effects of breathing gas at depth
pressure gradient is the difference in pressure between two connected regions
until equilibrium, there will be a gradient between the breathing gasses and the gasses in solution in the blood and tissue
