The popularity of freshwater spring diving has led to some confusion among divers about cave and cavern environments and the limitations that apply.


1) Spring Basins: Though connected to subterranean caves and caverns, these open-water pools require no special training or equipment. Access to the surface is not restricted, so divers can ascend directly to the surface in case of emergency. However, untrained divers must exercise caution and avoid entering caverns and caves. Stay in ambient light (both behind and in front of you). Often, the spring's owner or dive operator prohibits open-water divers from carrying dive lights.


2) Caverns: A cavern is simply the entryway to a cave where natural light penetrates and the entrance is always visible. However, the restricted environment may prevent divers from ascending directly to the surface and can present additional hazards including silt and confusing passageways. Caverns can be safely explored after a short training program and with a minimum amount of additional equipment. Some training agencies place certain depth or linear penetration restrictions on cavern divers.


3) Cave: At heavily dived sites, the entrance to the full cave environment is usually blocked by a locked grate or marked with "grim reaper" warning signs that make no bones about the deadly consequences of venturing inside. Cave certification and full cave diving gear are necessary to explore these restricted areas.


The Evolution of a Cave Diver


The path from open-water diver to full cave certification involves a progressive series of certifications that teach divers specialized techniques and introduce new gear.


STEP 1: CAVERN CERTIFICATION
A two-day cavern training course is the first step in the evolution from open-water diver to cave diver. Cavern students typically use their open-water equipment with the addition of two dive lights (a primary and a backup), a safety reel and an extended hose on one of the second stages. The course includes four cavern dives and about four hours of academics focusing on very basic line handling, buoyancy control and alternate finning techniques.


STEP 2: INTRO TO CAVE
This course is a true technical diving program, and intro students can expect a good dose of reality with their training. The training process is based on accident analyses and much of the academic program is about the mistakes cave divers make that lead to fatalities or injuries. For some divers this is quite a shift in thinking, and it accompanies some significant modifications in your gear. First, you'll need to swap your BC for a technical harness with back-mounted buoyancy wings. This is required to support the high-capacity single cylinder, two independent first-stage regulators, a primary dive light (at least 14 watts halogen or equivalent), two backup lights, a primary dive reel and a safety reel. You will refine the skills learned in cavern and learn procedures for finding a lost guideline, loss of light and gas sharing. This is a two-day course.


STEP 3: FULL CAVE CERTIFICATION
A Full Cave certification course starts with a slightly more complicated gear setup built around a set of twin high-capacity cylinders. Because decompression stops are a reality in long duration cave dives, a decompression cylinder is also required. In this course, the only new skill is complex line navigation where multiple lines are used to navigate more complicated systems. Emergency skills learned in previous courses are refined by practicing the skills over longer distances and with the increased levels of complexity expected on a full cave dive. A Full Cave course takes about four days to complete, including eight cave dives.