Neil Benjamin: Caves and Caverns

By: Kari Klaboe

[All photographs by Neil Benjamin]

At our August general meeting, Neil Benjamin presented an entertaining and educational program on caves and caverns: what they are, where you find them, and how you can dive in them.

Neil coming through the “tanks off restriction” in the X-line in the Pet Cemetery section of NaHoch (Sac Aktun).

Neil started the presentation by describing the distinction between a cave and a cavern. A cave “is a hole in the ground or in the side of a mountain deep / twisty / far enough in to leave the light zone behind” and a cavern “is a name for a short or entrance part of a cave, still in light zone”. With that primer complete, Neil took us through some fantastic photos of the different types of caves you can encounter: alpine, lava tubes, sea fracture, artificial, and solution caves. Solution caves or karst caves were the focus of Neil’s presentation and he covered their general formation, with the Mexican Cenotes used as an example of karst cave systems that are frequented by scuba divers.

Points of light TajMeha Jan 2014.

However, before you begin your cave diving adventure, proper training and the appropriate equipment must be considered. Neil covered some of the basic navigation equipment that is used by cave divers, including continuous guidelines, permanent guidelines, jump lines, primary reels, exploration reels, a compass, lights, and cave line markers. The cave line markers were interesting in that the shape and orientation of some markers can be used by cave divers to convey additional information regarding the dive or diver. For example, the orientation of a cave arrow or REMM (both different types of cave line markers) can communicate the direction of travel of the scuba diver that placed the marker or can indicate the way out of the cave. This information is not only useful to the scuba diver that placed the marker, but is also useful to the other divers in their group and potentially divers that follow after the group.

Another useful tool to a cave diver is a “jump line”, which Neil explained is used when there is a break in the cave guideline that the scuba diver is using. This can be a potentially dangerous situation for a diver, as the they are without a guideline for a short portion of the dive. The jump line is a temporary line that is used to go from one guideline to another guideline. Neil demonstrated how you would tie off your jump line to the cave guideline that you were leaving.

Sidemount set up and entry platform at CarWash Cenote.

One of the most important tools for a cave diver that Neil covered was the cave map. Significant work to develop vector maps of different cave systems has been performed by divers and Neil showed a variety of maps that are available. Many of the maps looked like colorful scribbles, so it also likely takes a significant amount of practice to become proficient at reading these maps.

Neil ended the presentation with photos of his cave and cavern dives in the Yucatan, Mexico with Bill Briscoe and Ajna Cackovic. He also showed videos of cave diving by Steve Bogaerts and HP Hartmann that are available on Neil showed their video of the Glass Factory dive in Abaco, Bahamas, but there are many amazing videos available in the video gallery:

When asked what the appeal of cave and cavern diving was, Neil responded that it’s extremely beautiful and the rock formations are spectacular. One only needs to watch the first few minutes of the Glass Factory video that Neil played to see this.

Thank you to Neil for presenting a wonderful primer on cave and cavern diving!

Ajna inspecting the Jaw’s formation on the mainline in NaHoch Na Chich part of Sistema Sac Aktun, the white cave near Tulum in the Yucatan, Mexico.

Also, thank you to Linda Phillips, Larry Dimitri, and the other Aqua Tutus club members that provided computer assistance during the meeting. The start of the presentation was unfortunately delayed due to some challenging computer issues involving a failed USB drive, but the group worked together to recover Neil’s presentation.