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Deep Diver

Knowledge Review - Part 1

Five (5) factors to consider when determining your personal deep-diving limit are:

  • environment: visibility, temperature, current
  • yourself: experience, emotions, health
  • previous (repetitive) dives
  • proximity of emergency care
  • your buddy

Determine if your equipment is suitable for deep diving:

  • regulator: balanced first stage, balanced adjustable second stage
  • submersible pressure gauge: regular service, mechanical SPG not reading high
  • buoyancy compensating device
  • cylinders: more air capacity is better
  • exposure suit: more insulation than usual
  • alternate air source: properly positioned, adjustable second stage, pony bottle
  • gauges and computers: depth gauge + timer, dive computer, compass

Five (5) pieces of specialized equipment recommended for deep diving are:

  • reference lines
  • emergency breathing equipment
  • extra weight
  • dive light
  • first aid and emergency oxygen

Proper ascent and descent techniques for deep diving:

  • ascend head up
  • use anchored or weighted reference line
  • track ascent rate
  • make safety stop

Avoid low on air or out of air situations by checking your submersible pressure gauge frequently.

Safety stop at 5 meters with a visual reference:

  • three (3) minutes
  • hold line so chest stays level
  • horizontal position is optimal

Prevent narcosis by:

  • avoiding hard work underwater
  • having experience with deep diving
  • avoiding alcohol or drugs
  • limiting anxiety
  • avoiding fatigue

Treat narcosis by ascending to a shallower depth.

Six (6) symptoms of decompression:

  • pain, often in the limbs, maybe joints. Pain can move over time
  • numbness, tingling or paralysis
  • unusual fatigue or weakness
  • skin itch
  • shortness of breath
  • dizziness and vertigo

Six (6) signs of decompression illness:

  • favoring an arm or leg, or rubbing joint
  • paralysis
  • unconsciousness
  • staggering
  • collapse
  • coughing spasm
  • blotchy skin rash

The primary reason divers get decompression illness is diver error.

Minimize risk of decompression illness by:

  • diving well within table/computer limits
  • making safety stops
  • adhere to conservative diving practices

Knowledge Review - Part 2

Proper deep diving objective should be nearly singular and specific.

Five (5) guidelines to follow when using a dive computer:

  • always use your dive computer as a no stop device
  • don't share computers
  • follow the more conservative computer
  • if computer malfunctions then make a normal ascent and a safety stop
  • don't follow you computer blindly

Maintain neutral buoyancy while deep diving by:

  • beginning dive properly weighted with an empty cylinder
  • while descending add air to BCD periodically to avoid very negative buoyancy
  • maintaining neutral buoyancy as you ascend

Two (2) techniques for estimating a proper ascent rate:

  • monitor ascent indicator on dive computer
  • use backup depth gauge and ascend no faster than 6 meters per 20 seconds

If divers discover they have accidentally omitted an emergency decompression stop they should not reenter the water and monitor themselves for DCS symptoms.

Five (5) recommendations that you should follow when making a deep drift dive:

  • make them from a boat
  • stay closely coordinated with you buddy
  • decide starting BCD inflation before entering water
  • tow an unanchored line and buoy
  • watch air supply and no stop times closely and allow extra margin with both

Four (4) guidelines to follow when diving near a wall:

  • watch your depth
  • dive as close to wall as possible
  • use wall as reference near the surface
  • ???

Ten (10) factors that may predispose a diver to decompression sickness:

  • dehydration
  • excess fat tissue and poor fitness
  • age
  • heavy exertion before, during or after dive
  • injuries and illness
  • use of alcohol
  • cold water
  • hot showers immediately after a dive
  • carbon dioxide increase
  • exposure to altitude

Steps to take if a diver is suspected of having decompression sickness:

  • have diver lie down
  • administer 100% oxygen if available
  • provide CPR if necessary
  • put in recovery position if unresponsive
  • contact EMS

A diver suspected of having decompression sickness should not be put back in water because:

  • requires extreme pressure
  • may take 6-10 hours
  • impossible for medical personnel to observe diver
  • worse if attempt incomplete