Scuba Notes Edit

Three Dangers in Scuba Edit

  1. Drowning - Happens when panicked
  2. Lung Overexpansion
  3. Decompression Sickness - Never come up faster than 30ft/min.

Seven Rules of SCUBA Edit

  1. Come up ASAP (As Slow As Possible)
    1. 30ft/min
    2. Safety Stop @ 50ft for 1 minute
    3. Safety Stop @ 20ft for 3 minutes
  2. Always breath slow and deep
  3. Watch your air supply
    1. Notify buddy and return to anchor at 1000psi
    2. Must surface at 500psi
  4. Stay with your buddy
    1. No more than 20ft away
    2. If buddy lost, search for 1 minute, then surface normally.
    3. Two buddy pairs stick together
  5. Don’t Dive too deep
    1. Max 120ft.
  6. Watch your time limit
  7. Check your buddy when you check your air

Four Causes of Decompression Sickness Edit

  1. Come up to fast
  2. Dive to deep
  3. Stay too long
  4. Dehydration

Boat Diving Edit

  1. Get to Know the Boat Captain (He is main rescuer)
  2. Surface current from surface to 30ft.
  3. Lines
    1. Anchor line – upwind
      1. Extra rope to set anchor angle is called scope
    2. Trail line – drifts downwind with float at end.
    3. Current line – runs from back ladder to anchor line.
  4. Hold onto trail line while you wait for your buddy
  5. Follow anchor line to the bottom
  6. Write anchor depth on slate.
  7. Note your compass direction leaving anchor.
  8. Note where anchor is on a wreck dive.
  9. Dive with reef wall on same side to easily reverse course.

Time Limits Edit

  • Time limits ensure nitrogen absorption level does NOT require decompression.
  • Any dive greater than 60ft have at least one hour rest. ** Called a deep dive.
  • Add 10ft of depth for strenuous (current) or cold.

Nitrogen Absorption & Oxygen Edit

  • Air is oxygen toxic at 218’
  • 100% oxygen is toxic at 20’
  • Air is 21% oxygen
  • Nitrox adds extra oxygen to air to reduce nitrogen absorption
  • Extra oxygen in Nitrox reduces your maximum depth due to oxygen toxicity.
  • Typical Nitrox of 32% or 36% oxygen, reduces max depth to 110 and 90 feet respectively.

Pre-dive Check Edit

Bruce Willis Ruins All Films!

  • B - BCD
    • BCD secure and functioning properly?
    • Low pressure inflator attached?
    • Appropriately filled for entry?
    • Buddy familiar with operation?
    • Tank secure?
  • W - Weights
    • Amount of weight appropriate?
    • System free and clear for emergency release?
  • R - Releases
    • All buckles and releases functional?
    • Locate releases without looking?
    • Buddy familiar with operation?
  • A - Air
    • Sufficient for dive?
    • Valve turned on all the way? (remember to turn a quarter turn back from all open)
    • Alternate air source properly located?
    • Familiar with buddy's alternate air source?
    • Air pressure on which to turn dive? (when to return back)
  • F - Fins (or Final Check)

Scuba Navigation Edit

  • Follow anchor to bottom
  • Note course when leaving anchor
  • If anchor is not visible from reef, mark an X in sand for point leave reef to anchor.
  • Record position, depth of anchor and course on slate
    • Position on a wreck or reef -- On top or in sand
    • Boat may be tied to the wreck, not to an anchor!
    • Note if anchor line goes over wreck/reef or away.
  • Shallow Dives
    • Swim till 1000lbs, surface, signal OK, take bearing, dive, swim back along bearing.
  • Deep Dives
    • Get shallower to preserve air
    • Get back to anchor from above.
  • At safety stop, be careful to NOT lift anchor. Do not pull up.
  • You CAN make your 50' safety stop while swimming to anchor.

Rescue Edit

  • Get to Know the Boat Captain (Main rescue person)
  • Someone must always be on the boat.
  • You must have three to do a rescue.
    • Do not try to tow a disabled diver unless absolutely necessary