The caves of the Riviera Maya in Mexico are complex low-to-no flow caves, requiring a competent level of trim, buoyancy and navigational precision.
Equipment should be as tidy and streamlined as possible, be readily accessible and in good working order for every dive.
Below are some Hogarthian configurations that are appropriate for cave diver training and the majority of backmount cave diving in the Riviera Maya.
TANKS
Nearly all double tanks locally are aluminium 80s with an isolator. Dissimilar tank issues are the exception, not the rule. Fills rarely go beyond 3000-3100 psi (200 bar). Most dives are no deeper than 50 feet / 15 metres and do not require enriched air, but EAN 32 is recommended and readily available.
BACKPLATE, HARNESS AND WING
A single bladder wing with 40 pounds (18 kilos) of lift is ideal for Mexico. Bungeed bladders will not be allowed for training and we discourage them for cave diving, since, should the bladder be punctured, the bungees can completely deflate the wing and are a potential entanglement hazard. Aluminium tanks are narrower than many steel ones, so a narrow profile wing design is suggested.
Aluminium backplates requiring no extra weighting are sufficient for most divers. Larger divers may consider a steel backplate (check first though, airline luggage weight restrictions are becoming draconian!). Any weights should be positioned above the waist.
A single strip of webbing is best. Plastic harness clips are unnecessary and not recommended, being a potential failure point.
REGULATORS
How to configure
In order to minimize drag, hoses should be the correct length for your body and be routed down and in.
Convenient first stages are those with 5 LP ports and a swivel turret (for example, the Scubapro MK 25), allowing the end port to be used, thereby crossing the hoses without obstructing the gas flow.
"Flathead" first stages (for example, some Apeks designs) are equally suitable, with hose routing again being down and in.
Types of regulators
The water is a constant 77° F (25° C) and most dives do not exceed 90 feet, with a vast amount of dives at no more than 50 feet. Depth here is not the issue it is in Florida, for example.
Therefore, simple, mainstream balanced piston first stages are suitable for most backmount cave diving in the Riviera Maya. Environmentally sealed first stages are equally appropriate (more so for sidemounting, since passages may be tighter and more likely to collect dirt) - just be aware that some regulators may be more difficult to service promptly. Remove any plastic covers that may (and invariably will!) dislodge in the caves. We believe divers should be in the overhead environment with DIN connectors only, since yokes can shear off under contact with the cave.
Simple second stages that can be opened underwater without tools are preferred, thereby allowing cleaning.
Hoses
Unless unusually large or small, most divers use a 7 foot (210 cm) hose for the primary regulator, which allows single file air sharing, routed down from the right post to the right hip, then diagonally across the chest, around the left side of your neck, with the second stage breathed from the right. A small dogclip should be attached to the end of the hose with cave line or O-rings - no metal to metal attachments! - for clipping off when not in use.
The backup regulator hose (22 - 24 inches / 55 - 60 cm, depending on body size) is routed from the left post behind the diver and is breathed from the right. The second staged should be attached to a suitably sized bungee necklace and hung around the neck.
The LP inflator hose (15 inches / 38 cm) crosses from the right post behind the diver's neck. The corrugated hose should be bungeed to the harness to avoid it slipping behind the diver's back.
The HP hose routes directly down from the left post. It can be attached either to the left hip D-ring (24 inches / 60 cm is a good size for most divers) or one of the chest D-rings, depending on length and preference. It is important that the hose be streamlined, whichever the choice. The hip D-ring is recommended since divers learn muscle memory by clipping/unclipping.
Hose protectors should be removed - they allow dirt to build up and can hide damage and small leaks.
Gauges
The submersible pressure gauge (SPG) is all that is required. No consoles, no rubber boots (see hose protectors above). A small dogclip should be attached to the end of the hose with cave line or O-rings - no metal to metal attachments! - for clipping off when not in use. Gauges may be calibrated in either psi or bar.
PRIMARY LIGHT
A canister primary light attached to the waistband at the right hip is the preferred choice, providing a convenient "holder" for the primary hose. A 10W HID or 35W halogen light is sufficient. Avoid unwanted sliding of the canister by attaching a second beltclip to the waistband webbing. You should be able to remove the canister underwater. A hard or soft handle is required, thereby allowing both hands to be free.
Dive lights and batteries are rapidly evolving for the better. Both HID and LED technologies are making rapid improvements in burn time and output. It is not unreasonable to imagine primary lights soon becoming the size of current backups.
BACKUP LIGHTS
Your two backup lights should be chosen with a view to attaching them to your chest D-rings and secured with bungee along the chest webbing for streamlining. If placed in a pouch, you/your team may not notice them if they accidentally switch on. A small dogclip should be attached to the end of the light with cave line or O-rings - no metal to metal attachments, which if entangled can spell disaster! - for clipping off when not in use. LED lights are becoming increasingly popular for their high performance in terms of output and relatively long burn time.
CUTTING DEVICES
A small (blunt-tipped) knife or Z-knife (needs to be checked regularly for rust) is required in the event line needs to be cut. For such an essential safety tool, we recommend two cutting devices, stored separately, should you lose or be unable to reach one of them. Waistband/pouch/pocket and wrist or both wrists are two suitable choices.
SAFETY REEL/SPOOL
A safety reel or finger spool (each has its pros and cons) with at least 100 feet (30 metres) of line is required. Again, for such a key safety tool, we recommend two, stored separately, should you lose or be unable to reach one of them. Left waist D-ring and pouch/pocket or left waist D-ring and butt D-ring are two suitable choices.
PRIMARY REEL
Each dive team should bring one primary reel without a brake (minimum length 350 feet / 110 metres). We do not advocate the sharing of reels, not even the primary, since this has been a contributing factor in some past fatalities.
JUMP/GAP REELS/SPOOLS
Cave diving in the Riviera Maya often involves complex navigational decisions. Ensure you bring enough reels/spools (and no more) to complete your dive plan.
POUCH/POCKETS
Waist pouches and thigh pockets (whether attached to the divesuit, strapped on or on neoprene shorts) are convenient locations for your dive tables and accessory equipment. They should all be streamlined and provide easy access. Pockets/pouches should have internal D-rings for attaching your accessories.
DIVE PLAN SUPPORT
We suggest one wrist computer (ideally with enriched air options) and one wrist bottom timer (or computer in gauge mode), along with air dive tables (certified cave divers are encouraged to bring enriched air/accelerated deco tables as well). Flexible IANTD tables are ideal.
WETNOTES
While many divers use slates for dive planning, we recommend wetnotes, which allow for detailed dive planning as well as acting as a logbook, without the need to rewrite the details. Remember to bring spare pencils!
EXPOSURE PROTECTION
While the water is a constant 77° F (25° C), cave training and diving can keep you in the water for extended periods, therefore we recommend at least a 5-7mm full wetsuit with a hood (for protection and securing long hair). No gloves are required since you should not be touching anything other than your equipment, your buddies and the guideline. Drysuits are appropriate for longer dives and for those who chill easily.
FINS
Cave diving finning techniques make split fins impractical and they are not permitted during training. Many cave divers use short, rubber fins (for example, Scubapro Jetfins) while others may feel more comfortable in a wetsuit using lighter fins, which must be fairly rigid (the Mares Avanti Quattro is a popular choice). Loose fins straps should be taped down or have springs/bungee. Freediving fins are not appropriate, since they are too long for cave diving.
MASK
Most masks are appropriate, unless you are planning to use a DPV, when a low-profile mask reduces buffeting. Mask straps should be taped down (to avoid possible entanglement), alternatively the mask may be placed under the hood. A second mask is a matter of personal preference and may be useful for dives with deco obligations, where gas switching and checking gauges require two free hands.
PERSONAL MARKERS
For training, 4 markers are required - 2 directional markers (line arrows) and 2 non-directional markers (REMs or cookies). Referencing exit markers (REM) may be used in place of cookies and are encouraged for cave divers. Most caves in the Riviera Maya have no system distance markers and any system arrows may be limited to marking jumps. You may want to bring more directional markers than usual, should you want to reinforce your exit direction from time to time.
GENERAL NOTES
Whether you are a trained cave diver or are signed up for cave diver training, feel free to contact us regarding purchases of new equipment or choosing the best equipment for the job.
The above guidelines are our personal recommendations for cave diving in the Riviera Maya in Mexico and, while they meet (and indeed go beyond) NSS-CDS cave training standards, they do not necessarily reflect the views of that training agency.
The choices are not "holistic" and we do not embrace philosophies that advocate only one way of diving. So long as an individual's configuration is safe, efficient and explained to other team members, we believe personal choice is the better.
If you are considering diving sidemount in Mexico, please contact us for any information you may require.
Dive safely.
Ela Bertoni (NSS-CDS # 363) and Adam Korytko (NSS-CDS # 364)
CAVEHEAVEN
Puerto Aventuras, Riviera Maya, Mexico
http://caveheaven.com
