Scuba Diving Checklist: Cavern Diving

Proper preparedness is key in our sport, so checklists can be extremely useful, and DAN agrees. But what exactly appears on a checklist can vary.

Of course there’s standard gear for every dive: wetsuit or drysuit (or simply a rashguard if you’re in very warm waters), tank, BCD, regulator, fins and mask. Add a bit of personal gear, such as a camera, and on most dives that’s pretty much all you’ll need. But certain types of dives or those with a specific purpose call for specific pieces of equipment that you wouldn’t normally bring.

In this series of articles, we’ll help you put together checklists for various types of dives, this time for cavern diving. Note that we’re speaking specifically about cavern diving so you’ll be diving inside caves, but not beyond the light zone (the place in the cavern where you can still see the light from the entrance). Anything beyond the light zone is considered cave diving and is therefore a technical discipline.

Redundant air source and regulator

As soon as you head into an overhead environment, such as a cavern, you should not rely on a single air source. At the very least, a separate backup regulator adds an extra level of security. Note that this is different from the traditional octopus — whereas an octopus is a backup second stage attached to the same first stage as the primary, here we are suggesting a separate regulator entirely, with its own first and second stages. This can be attached to a secondary valve on the same tank as the primary regulator, or onto a separate bottle. The latter is preferable, as you then have an entirely redundant air supply. Technical cave divers use two full-size tanks, each with their own regulator. If one fails, whether it is the tank, the first stage, or the second stage, you still have a complete backup ready. For cavern diving, a pony bottle with a regulator should be sufficient, though, if you’re not quite ready to go with full doubles.

Light, and lots of it

Even within the light zone most caverns are dark, so a good dive torch is a necessity. A powerful light will not only allow you to better navigate, but will also take in the sights of the cavern. And, because dive torches do sometimes fail, a backup is a necessity here too. Ideally, you’ll have two backups. That way both your primary torch and your backup would have fail before you’d find yourself in the dark, so to speak.

Many dive organizations recommend that your primary torch should run on rechargeable batteries, for economic and environmental reasons, but that your backups should run on ordinary batteries. This is because your primary torch will see more action that your backups, so being able to charge it between dives is highly useful. But ordinary batteries have a small edge in reliability according to some, so the backups should use these. Modern rechargeable batteries tend to be very reliable, however, so this recommendation may be outdated.

Line reel

Even if you’re not venturing into a deep cave, a line reel can still be quite useful for cavern diving. While you should, at any time, be able to see the light from the exit, there can still be situations where finding it can be tricky, such as if someone accidentally kicks up a silty bottom. Being able to backtrack your way to the exit using a line reel can be a good form of insurance.

Backup mask

Swimming in overhead environments increases the risk that your mask is accidentally pushed off your head by an outcrop, and seeing as you cannot simply make your ascent directly from your position, a backup mask is very useful. Keep it in a drysuit, wetsuit, or BCD pocket, ready for deployment. Any mask will work, though there are specific backup masks, which are lighter and more flexible. Whether you choose a purpose-built one or not, make sure it is compact and low-volume.