Notes

• NACD (formed in Gainesville in 1968) - National Association of Cave Divers
  -gave their first certification in the early 1970s
• NSS (formed in Huntsville in 1947) - National Speleological Society
  -considered to deal well with landowners
  -the CDS (Cave Diving Section of the NSS) was a splinter group of the NACD
  -in the last 15 years, the NSS-CDS has become more training-oriented than the NACD

• PADI
  -teach cavern only based on the CDS cavern outline
• NAUI
  -teach cavern and cave with cave being taught by NACD/CDS instructors who wanted insurance for cave instruction
• YMCA
  -used to teach both cavern and cave, but now just do cavern - they used CDS instructors, but would issue a YMCA card

• IAND (International Association of Nitrox Divers), which evolved into the IANTD (International Association of Nitrox and Technical Divers) started by Tom Mount
  -taught nitrox, deep air, cave (teach slightly different than NACD or CDS with no apprenticeship to become an instructor)
• TDI
  -most places don't take TDI because it only takes 2-3 days to become an instructor
• GUE (Global Underwater Explorers)
  -tried to change NACD standards, because they wanted more instruction

Levels of Cave Training

GUE Cave Levels (Check out the GUE Classroom for more details)

• Cave 1 (12 dives) - use doubles, maximum penetration to a total of 1/6th of backgas
• Cave 2 (10 dives)
• Cave 3 (10 dives) - dive-based, with no comparable class from the other agencies

Accident Analysis

The stats for this subject go back to approximately 1961, although they have not been kept for the last 8 years. Many of the deaths occurred during solo diving, so unless there were obvious indicators as to the cause of death, these incidents were not included.

The 5 Causes of Death in Caves:

1. Lack of training
2. Lack of a continuous guideline to the surface
3. Not following the thirds rule of gas management
4. Diving too deep with improper gases
5. Not having 3 lights

Of the approximately 450 cases used in these analyses, only 45 were certified cave divers. Since certified cave divers are considered to have sufficient training, and as a part of this, should know to carry 3 lights, these two causes are eliminated from their causes of death.

The 3 Causes of Death of Certified Cave Divers:

1. Diving too deep with improper gases
   -these deaths occur from either narcin' or oxygen toxicity, where depth is relative to the O2 content of one's gas supply
2. Lack of a continuous guideline to the surface
3. Not following proper gas management procedures for the particular dive

GUE Cave 1 Limits

1. Can only dive one sixth of doubles
2. 100 foot maximum depth
3. 30 foot minimum visibility
4. 80 cubic foot starting pressure
5. No planned decompression
6. Main line only
   -no jumps (going from main line to side line)
   -no traverses (starting at one opening to the surface and exiting at another)
   -no circuits (going in circles - must go out the way you came in)
   -can do gaps (discontinuation of a line, usually occurring at a sinkhole)
7. No restrictions (somewhat ambiguous)
8. Must stay within personal limits
9. Must stay within team limits

3 Forms of Communication

1. Hand and Light Signals
   - includes command signals such as OK, Call the Dive, and Hold - these signals must be done and acknowledged with the same signal to have occurred
2. Writing on a slate
3. Touch Signals

Team Order

This section was a discussion on the order of members entering and exiting a cave. In general, the first one in is the person running the reel. They are the last person out as they take the reel out. The other team member(s) stay in their respective positions as well, so the last person in is the first person out. This can change if there is a light failure or gas-sharing incident. The person with the failed light should be in the middle of a three person team and in the front of a two person team on exit from the cave. This makes it possible for at least one of the other team members to see if the person without a primary light is trying to signal someone, since their secondary light will not be near as bright as the other team members' primaries. When a light failure occurs the team members must signal each other as to the new order of exit, and then proceed out.

Pre-Dive Checks

4 In-Water Pre-Dive Checks:

1. Equipment Check
   -checklist making sure all equipment is accounted for and functioning
2. S(afety)-Drill
   -deploy long hose to other team member, swim a little ways sharing air, and then switch roles
3. Bubble Check
   -check for any bubbles coming out of the gear, possibly indicating equipment malfunction
4. Review the Dive Plan
   -this step also includes gas planning, where one's penetration pressure is calculated

Dive Planning

Factors to consider before a dive:

• Maximum depth
• Gas planning with Maximum Operating Depths (MODs) based on gas mixes
• The dive site
• The maximum dive time and the turn time
• Team limits
• Team order (who runs the reel)
• Tides (dive during outgoing tides if applicable)
• "Special stuff" - various miscellaneous factors that can vary from site to site and dive to dive

Emergency Procedures (What Can Go Wrong)

1. Manifold
   -the isolator could be closed (indicated by a pressure gauge that reads too high, and is not dropping); broken knobs; burst o-ring; roll off on the left post
2. Drysuit
   -floods; overinflates (disconnect, or turn reg off and then disconnect); seals too tight
3. Light fails
   -stop moving and secure the line (touch something to stay oriented)
4. Regulators
   -if leak cannot be isolated or stopped quickly, close the isolator and breathe off of the bad post (this is only if the leak cannot be stopped, so since you are going to lose this gas anyway, use as much of it as you can) - check both posts first before shutting off isolator
5. Out-of-Air
6. Air Sharing
7. Fins
8. Mask
9. Bottom Timer/Depth Gauge
10. Wing
11. Disorientation
12. Lost
    -if you are lost, stop and cover your light - if you can't see anyone else, perform 3 searches:
    • 1st search - look around for other lights with your light covered
    • 2nd search - look around with your light (you're looking for clues of others or of where you came from such as silt, bubbles, or anything familiar)
    • 3rd search - performed using safety spool
    -if your buddy is lost - follow the same procedures as above
    • 3rd search - put a line arrow on the main line and pull out safety spool - wrap line around arrow and search away from the main line - continue searching until you reach your turning pressure or recalibrate your thirds
13. Entanglement
    -stop and signal buddy and attempt to free oneself one time - after that let your buddy do it - if you have to cut the line, make sure everyone is on the exit side, signal the cut, and then cut - after untangled, tie the line back together
14. Injury/Medical Problems
15. Collapse
16. Silt out

4 Types of Caves

1. Coral Cave
   -hazards are currents and hang-ups
2. Sea Cave (Littoral Cave)
   -hazards are surge, differential currents (change from outside to inside)
3. Lava Cave
   -can go back very far
   -hazards are black walls (absord light), abrasive walls, and tidal fluctuations
4. Solution Cave
   
   • vadose zone - area in a cave above the water table
     
   • phriatic zone - fully saturated zone of a cave
     
   -Factors affecting velocity of current:
   
   • changes in elevation
     
   • restrictions
     
   • backpressure of river system (can fluctuate greatly)

Hazards of Diving in Caves

3 Common in Any Cave:

1. No natural light
2. No air
3. Overhead environment

Others:

• Silt (bottom seds.)
  • sand
  • mud and mung (muddy particles in marine environment) - organic
  • clay - hard to disturb due to its very small particle size - takes forever to come out of solution
  -current determines silt contents
• Tannic acid
• Halocline
• H₂S (hydrogen sulfide) - when it goes into solution, it can absorb through skin (it is toxic) - milky looking
• Passage configuration
  • small tunnels - easier to get tangled and stir up silt - harder to get lost, lights more effective
  • larger tunnels - easier to get lost - harder to stir up
• Current
• Human failures

Dissimilar Tanks

Tank Markings:

Tank Volumes:

The math is easy when calculating turnaround pressures for a team of divers when all of them are wearing the same size tanks. A third of the air of the person who has the least amount of air in their tanks is taken, and subtracted from everyone's volume. To make calculations easier, the initial volume is rounded down to a number that can be easily divisible by 3. For example:

• Diver A has 3200 psi in a set of 104s
• Diver B has 3100 psi in a set of 104s
• Diver C has 3400 psi in a set of 104s

  The person with the least amount of gas is Diver B at 3100 psi. To make the calculations easy, 3100 is rounded down to 3000. A third of 3000 is 1000. 1000 is then subtracted from each of the team member's starting pressures making everyone's turnaround pressures the following:

• Diver A = 2200 psi
• Diver B = 2100 psi
• Diver C = 2400 psi

When calculating turnaround pressures for a team of divers who are wearing tanks of different sizes, it becomes a little more difficult. One must figure out a baseline for each size tank, which can then be applied to figure out tank volumes. The baseline is just how many cubic feet of air exist in a given tank at 1 psi. The calculations for a steel 104 are given below:

The problem is set up as ratio to give us the amount of cubic feet for every 1 psi. The opposite can also be done to figure out the number of psi for every cubic foot. The following table contains both baselines (cu. ft./psi and psi/cu. ft.) for some common tank sizes.

These numbers are then used to calculate who has the smallest volume of gas at the beginning of a dive. The following steps are followed to calculate the turnaround pressures for a team with dissimalar tanks:

1. Figure out who has the smallest amount of gas
2. Calculate a third of the smallest amount
3. Convert the smallest psi to volume (cubic feet)
4. Take this volume and convert it to psi for the larger amount of gas
5. Calculate a third of the larger amount of gas

An example:

• Diver A is diving with a set of LP steel 95s filled to 3200 psi
• Diver B is diving with a set of LP steel 104s filled to 3000 psi

1. Who has the smaller amount of gas?
   
   • Diver A (3200 psi x 0.036 cu. ft./psi = 115 cu. ft. in one tank or 230 cu. ft. in their doubles)
   • Diver B (3000 psi x 0.039 cu. ft./psi = 117 cu. ft. in one tank or 234 cu. ft. in their doubles)
   • Diver A has the smaller amount of gas, although not by much.
2. What is a third of the smallest amount?
   
   • Diver A has 3200 psi, so to make the calculations easy we round down to 3000. A third of 3000 is 1000 psi.
3. Convert the smallest psi to volume (cubic feet).
   
   • 1000 psi x 0.036 cu. ft./psi = 36 cu. ft. in one tank or 72 cu. ft. in their doubles
4. Take this volume and convert it to psi for the larger amount of gas.
   
   • 36 cu. ft. x 25 psi/cu. ft. = 900 psi
5. Calculate a third of the larger amount of gas.
   
   • 3000 - 900 = 2100 psi

• Diver A turns at 2200 psi
• Diver B turns at 2100 psi

The above calculations can be rather difficult to do in the field, especially if you're in the water and don't have a water resistant calculator handy. To get around this problem, there is a chart available that shows tank volumes at incremental psi s. To print a copy of this chart, go to Harry Averill's Cave Diving web site at the following address:

http://www.cavediving.com/how2/table.htm

He also includes an explanation of dissimilar tanks and gas matching at:

http://www.cavediving.com/how2/turnrnd.htm

End of the Notes