When you sit in a car and set off on a journey, you don’t expect to be involved in a collision but we still always take the precaution of wearing a seat belt anyway, and everyone hopes they make the journey complete without the hassle and inconvenience of getting a flat tire though we still always carry a spare tire/wheel, and when we drive into unfamiliar areas most drivers these days are equipped with GPS navigation systems or carry maps, so redundancy and self-sufficiency are essentials components of a car journey or road trip, should problems occur.
Yet as an active dive professional for the last 15 consecutive year, I often ask myself if most recreational divers, when diving at the outer edge of recreational diving limits in the 100ft/30mt to 130ft/40mt range, were to encounter problems underwater such as disorientation, loss of buddy, out of air, accidentally overstaying their no-decompression limits to entanglement, would they be comfortable making it safely and slowly back to the surface, would they have the self-sufficiency and redundant equipment that might be needed.
In most dive training programs at the entry level, and even beyond, divers are typically outfitted with a single cylinder of air/nitrox, with a jacket style BCD, and a regulator with an alternate (octopus attached), this equipment vary rarely evolves within the recreational realm regardless of depth and as the diver gains experience diving deeper, though a small percentage of divers may go further and carry a spare air/pony bottle device, this is more the exception and norm. Whilst diving in the 100ft/30mt – 130ft/40mt range in warm tropical waters, with good visibility very rarely presents problems should the dive go well and as planned, if a recreational diver in this range were to suddenly face hazards and have to manage problems, they would find their reactions delayed and thinking impaired, even more so in colder waters and with lower visibility and more environmental challenges. In recent years some of the technical dive training agencies have even advocated the use of helium to supplement recreational breathing mixes to minimize narcosis.
When recreational divers think of technical diving, the image of a 250 lb/120 kg male with double steel 120 cubic foot/16 litre tanks on their back, dressed in all black, and with enough gadgets to be the envy of a newly decorated Christmas Tree, springs to mind, and as such may find this off putting and not the training path they wish to pursue, or time and financial commitment to the equipment purchases needed for tec diving.
However there is a program that any recreational diver, who wishes to dive in the 100ft/30mt – 130ft/40mt, should consider and boosts their confidence and skills for deeper recreational diving, without the time, cost and equipment commitment needed for typical and traditional recreational diving, and within the PADI training system is known as Tec 40, denoting the depth limits of 130ft/40mt and building a divers confidence and skills set to solve problems in this range, such as loss of air, entanglement, narcosis, buddy separation, so they can easily make it back to the surface safely. Although most people chose to take her training with double manifold tanks on their back, a smaller stature person, has the options of 1) Side mount with 2 tanks slung on each side of the body, or 2) use standard recreational gear carrying a stage tank with the same breathing mix. This allows the diver to have a redundant air supply at depth should they occur a catastrophic hose/o-ring failure at depth, remember it’s one thing to handle a car with a blown tire whilst driving at 30km an hour, and another thing to handle a blow out at 90km an hour, and handling out of air/lost gas scenarios at depths of 30mt/100ft – 40mt/130ft requires quicker reactions and redundancy than diving at shallower depths around 12mt/40ft – 18mt/60ft.
In addition to learning about the equipment that should be carried and configured for diving in the range of 30mt/100ft – 40mt/130ft, the entry level PADI Tec 40 course also teaches divers how to plan dives beyond the recreational time limits, and most computers and dive tables allow a no decompression limit of 20 minutes at 30mt/100ft, dropping to just 8 minutes at 40mt/130ft. Yet entanglement or narcosis can always cause a diver to overstay these limits, particularly when diving wrecks where monofilament line may be a hazard, or if distracted by mesmerizing aquatic life and taking photographs this can also cause divers to accidentally to stay beyond their limits. The PADI Tec 40 allows divers to clock up to 10 minutes of a decompression obligation, which allows extended bottom time at depth, maybe just enough to get that photo opp of a lifetime and return to the surface safely if alone for some reason, and tell your buddy all about it!