Cave diving equipment has some similarities with recreational scuba diving equipment, but there are some very important differences too. Here, we’ll take a quick look at specialized gear for cave diving including double tanks, exposure suits, cutting tools, and DPVs.
Double Tanks
Unless you are a rebreather diver, you will be using double tanks (cylinders) during cave diving. Carrying a set of doubles reduces the amount of weight needed, and they ensure that you have plenty of air. Most cave divers and technical divers prefer large-volume low pressure steel tanks manufactured by companies such as Faber and Pressed Steel. In the United States, these cylinders usually have a working pressure of 180 bar (2,640 psi). Popular sizes include 80, 95, 104, 110, 112, 120, and 130 cubic feet. Aluminum 80 cylinders are sometimes used; they are lighter than steel ones, but their buoyancy characteristics are different, particularly if you find yourself low on air. No matter which tanks you settle on, be sure that you weight yourself so that you can remain submerged at a depth of 20 feet if your cylinders are empty.
Exposure Suits
Caves and caverns are chilly inside! Your exposure suit needs to keep you warm, and it also needs to be designed to withstand the occasional abrasion that can happen inside a rocky cave environment. A 7mm wetsuit will be enough if you’re diving in caves where the water averages 65 to 72 degrees Fahrenheit, but if you’re spending time in water colder than that, you need a drysuit – and you’ll also need to be drysuit qualified.
Cutting Tools
Your standard dive knife is a good start, but for cave diving, you’re best off if you carry some additional cutting tools. Line cutters are designed specifically to grab and cut line without damaging anything nearby; scissors are a good alternative but the potential for an accident is greater. Don’t skimp on cutting tools – get good ones that are strong enough to cut through tough line. Even if you and your team are careful with your lines, there’s a potential for entanglement in line someone else has left behind. Keep your cutting tools within easy reach and develop the muscle memory to grab them in an emergency.
DPVs (Scooters)
Some caves are the perfect setting for DPV use, and DPVs are prohibited in some places. You’ll be best off with a ride behind DPV rather than a ride-on DPV; these are easier to manage and can be used even in fairly small spaces. Be sure that you plan for battery burn time, configure your gear correctly to eliminate drag, and get the proper training and education required for the DPV you choose. Be sure to practice with it in open water before taking it into an overhead environment.
These are just some of the items you’ll need when cave diving – remember to always carry a primary light and two backups, and be sure that you have properly configured valves and regulators. Last, but certainly not least, remember that appropriate gear is no substitute for training. Obtain cave diver certification before even considering entering a subterranean chamber.