[h=3]THE CAVERN TOUR[/h]Cavern tours are offered by qualified certified full cave divers who have earned a minimum Divemaster rating in the leadership structure. The purpose of these standards is to assist the growing needs of professional open water scuba instructors, who guide recreational divers into caverns found in north Florida, the
Bahamas and the Riviera Maya of Mexico´s Yucatan peninsula.
[h=4]LIMITATIONS:[/h]1. Natural daylight and an unobstructed ascent to the surface
2. Maximum linear distance from surface: 200 feet
3. Maximum depth: 100 feet
4. No restrictions
5. No decompression
6. Minimum visibility: 40 feet
7. Guide ratio: It is strictly 4:1 maximum.
8. Minimum psi/bar to begin cavern dive: 2000 psi/140 bar.
9. Minimum tank pressure to exit cavern zone: 1200 psi/80 bar or 20 cu. ft.
[h=4]GUIDE QUALIFICATIONS:[/h]Following two are required:
1. Certified full cave diver and
2. Certified as a qualified, certified Divemaster.
2. Recommend being an Open Water Instructor.
The Guide must use full cave gear configuration. Double tanks are required for air/gas management, handling of potential emergencies and as an example to potential students. No single tanks with dual outlet valve or side mount configurations are allowed to be used by the Guide.
[h=4]PROCEDURES:[/h]1. Detailed briefing before each dive
2. Explanation and review of rules for cavern diving
3. It is not necessary to go through extensive equipment modifications for the
cavern tour because it is considered a controlled experience. Minor
changes may be necessary, such as the addition of alternate air source,
removal of snorkel, and proper weighting.
4. Use of the guideline is essential to ensure a safe dive and demonstrate
proficient skills. It is recommended that the guide demonstrate proper
overhead protocol at all times.
5. No diver participation is mandated
6. Definitions:
a. speleogenesis and hydrology
b. cavern/cave environment (unique and fragile)
c. accident analysis
d. problems
7. Techniques
Brief review of:
a. buoyancy control
b. finning techniques
c. light use and signals
8. Review of basic communications
a. “OK”
b. “Stop or Hold”
c. “Dive is over, exit”
d. “Out of air”
e. Instructor’s choice for additional hand signals
9. Dive Plan
10. Complete post dive review:
A Guide should stress that divers on a tour are under supervision and in a controlled environment. Urge the divers to participate in a cavern course if they wish to pursue cavern diving.
1. Equipment:
Equipment is the same as for a cavern course. Standard open water scuba equipment with two battery powered lights
Cavern Tour Briefing Recommendations
It is recommended that critical aspects of the following outline be incorporated into the dive briefing for cavern touring.
I. This is a Cavern Tour NOT a “course”.
II. DEFINITIONS:
Cavern - Limits
1. Area with ceiling and some visible light from the sun
2. Large with no restrictions
3. Minimum visibility of 40 feet (12 meters)
4. Depth: Recommend 70 feet (23 meters) or less
5. Penetration: Maximum 200 linear feet (65 meters) from an opening
6. No decompression
Cave.
1. Beyond the sunlight zone
2. Extensive training is required: (A course takes a minimum of 7/8
days.)
3. Different equipment is necessary: (Double tanks, redundant
equipment)
III. ENVIRONMENT
Unique and fragile.
Dive gently.
Conservation.
1. Take nothing
2. No grabbing or pulling on speleothems
3. Try not to touch sediments
IV. GEOLOGY
The Yucatan peninsula is limestone rock.
1. Ancient sea bed
2. Sedimentary layered rock
3. Porous
4. Erosion from water forms the passageways
5. Speleothems form during dry periods (ice ages)
V. TECHNIQUES
Buoyancy and propulsion
1. Minimize weight (buoyancy check before the dive)
2. Neutral buoyancy
3. Gentle kicks from the knee and ankle, not the hip
Body positioning
1. Slight head down, feet up
2. Midwater positioning (stay off the bottom, away from the ceiling.)
VI. COMMUNICATIONS:
Light signals
1. OK: circle
2. Attention: wave light slowly side to side
3. Emergency/Assistance: rapid waving of the light
Hand signals
1. OK 4. Air status 2000 psi/1200 psi (140 bar/80
bar)
2. Stop/hold 5. Out of air
3. Turn the dive 6. Call the dive - Exit. (Any reason, anytime)
VII. ACCIDENT ANALYSIS
1. Training - if people have an interest in cavern diving it is
recommended they take a cavern course.
2. Guideline - continuous to the open water. Redundant reference
to the exit.
3. Air/Gas - 2000 psi (140 bar) to turn the dive. 1200 psi (80 bar) to exit the overhead environment.
4. Depth - maximum 70 feet (23 meters)
5. Light - minimum three lights: (Natural daylight and two battery
powered lights)
VIII. ADDITIONAL CONSIDERATIONS:
1. Equipment check, bubble check
2. No snorkel, no knives
3. Do not swim under the guideline
4. Halocline (some divesites)
a. saltwater is below the halocline, fresh water is above.
Rules that you refer to were formed by statistics-- look at deep air, once accepted due to lack of any other option, it took collecting data to prove it was a bad idea, and even the strongest of opponents had to eventually admit that the data didn't support their decision to continue doing it...
