The ABCs and How They Will Keep You Alive

One of the first things you learned in your Open Water course was the ABC’s before you enter the water. Occasionally people have a hard time remembering what the ABC’s stand for and definitely need some reminders. Others who consider themselves veterans of the sport get complacent and skip right over it.

In 2008 DAN conducted a study of diving accidents and when they occur during a dive. 26% of these accidents take place on the surface or before a completed decent. A further 24% of these accidentsoccurred on the surface after ascending from a dive.

Lets look at an unofficial scenario, a certified diver who has not gone through his ABC’s jumps in the water without his air on and no air in his BC. Luckily this diver was intelligent enough to stick the regulator in his mouth before the giant stride. As he starts sinking below the surface, and goes to take his first breath while simultaneously trying to add air in to his BC, the horror sets in when he realizes his air is not turned on! Fortunately this diver is not a novice and is flexible enough to reach back, turn his air on, kick with all his might to stay up, and equalize his ears since he is sinking. Assuming he is capable of turning the tank valve on, he is now able to get that breath he has been struggling for. Now, to add extra stress to this divers life, he also realizes he forgot to hook up the inflator hose to the BC. This will force him to do one of two things, try connecting the inflator hose or try to orally inflate. The connection is made and relief consumes him. Then one look at his gauges tells him he accidentally grabbed a nearly empty tank. Starting with near empty tank combined with his stressful breathing rate has made the cylinder quickly approach 0 PSI. Luckily he was able to make it to the surface and climb back on the boat to grab a new tank, if he is still up for a dive. For a veteran such as this fictional diver, this may just be a stressful and very embarrassing way to begin their dive. For others this scenario could mean a death on the surface before they even get to complete their long awaited dive.

To avoid situations such as that, lets take a closer look at the ABCs

A – Stands for more than just “air” or is your air on? Are ALL of your regulators performing ok? Are your regulator hoses routed or clipped in a way that they could be donated in the event of an emergency? Are you breathing from the correct tank? Have you analyzed the contents of what you are breathing? Does your air taste or smell funny? Are there any noticeable leaks?

-To know if a regulator is performing satisfactorily you really need to try it in the water. You will not know how well it is breathing, or if it has a leak in the mouthpiece etc until trying it in the water. (This is why this is also part of the Safety Drill)

B – Stands for BC, for most people this simply means putting air in the BC. This should be taken much further. Is the BC inflated? Are the inflate and deflate mechanisms working? Is the BC attached to your tank and or harness correctly? Has the wing or BC been inspected for damage? Is the back-up inflation system working properly? (ie dual bladder wing or drysuit) Are all clips accessories, straps, and integrated weight pockets attached securely?

C – Stands for console, computer and any other gauges. If you just let your computer turn on with the wet contact points as it makes contact with the water you will not be able to check the battery level. Checking your computer includes checking all the settings. Is the Altitude set correctly? Is the conservatism set correctly? Is the desired Algorithm selected? Are all the planned/contingency/deco gases programmed? Is the correct gas selected to start the dive? If using a transmitter is it working correctly? If using a transmitter you also have to have the computer on to check your air pressure. When was the last time you replaced the battery in the transmitter?

Tech divers are taught to take the ABC’s one step further and do a Safety Drill abbreviated as S-Drill. This is done in the water and should be completed before EVERY dive. Any S-Drill is meant to be done as a buddy pair or in a team. If solo diving the S-Drill should still be completed just as it would be with a buddy or a team. The biggest difference is a mirror is needed in a solo S-Drill to do a self-bubble check. I challenge you to think through any dive accident you have read about and try to see where the S-Drill would not have prevented it.


A HH CCR Class in Troy Springs, FL. Photo by: Dan Wright

CCR S-Drill

  1. Confirm BOV is functioning – Switch to the BOV, take a couple breaths and signal your buddy that the BOV is OK, by pointing to your BOV followed by giving the OK signal. If diving with a DSV, confirm operation and watertight seal.

Note: Never test breathe a regulator with Hypoxic mixes at the surface!

  1. Confirm Off-Board Bailout – Physically pull out the stowed regulator and breathe off of it. After taking your two breaths pass it to your buddy and let him confirm it works as well by breathing off of it. After all, in an emergency this gas could be for him. (See team bailout procedures). Repeat this for all Bailout/Stage bottles. Then properly re-stow regulators and check SPGs.

Note: Never test breathe a regulator with Hypoxic mixes at the surface!

  1. Check Line Cutters- Pull out each line cutting device show it to your buddy. After receiving the OK from your buddy re-stow the line cutter.
  2. Check Lights – One at a time pull out each light, and turn it on and confirm battery is working. After you receive the OK from your buddy, re-stow the light. This should be repeated for all of the required lights for the dive, ie for a cave dive check all three lights. If using the screw on switch, press against it to confirm the pressure at depth will not turn the light on. This is a good time to get in the habit of turning a light on BEFORE unclipping it.

Note: After using a back-up light during a dive, the batteries should be replaced prior to the next dive. After all, new batteries are cheap insurance.

  1. Check Reels/Spools – Pull each spool out of pockets, or unclip from behind you. Verify line is stowed properly on all reels/spools.(A complete reel/spool inspection should have been done prior to entering the water.) After receiving the OK from your buddy restow all reels/spools.
  2. Check Lift Bags/Surface Markers – Verify location. (If inspected prior to entering the water, there is not a need to inflate the bag during S-Drill but this skill should still be practiced frequently)
  3. Check Inflation/Deflation Mechanisms – Make sure all of your inflate/deflate mechanisms are working correctly. This includes, your wing, backup bladder, drysuit etc.
  4. Check All Other Equipment Required For Dive
  5. Bubble Check – Diver should signal (to) his buddy to check him for bubbles. While the buddy is observing, do a slow helicopter turn. As the diver turns they can point to their first stages on the rebreather and bailout as well as the loop/counter lungs to remind the buddy of specific places he should be watching for bubbles.


Why the S-Drill is important

CCR S-Drill

  1. Confirm BOV is functioning – By switching to and breathing off of the BOV you confirm it is working correctly. This is also a great review of the steps to bailing out in an emergency. Builds muscle memory and confidence.
  2. Confirm Off-Board Bailout – The best way to test a regulator is to try it in the water. Most CCR divers dive with the bailout on. (At least the bailout mix they will be switching to in an emergency) If you practice this before EVERY dive, retrieving and stowing your bailout regulators will no longer be a dangerous struggle but a smooth, rehearsed easy motion. It will also encourage you to configure and route your gear in an easy, simple and safe method.
  3. Check Line Cutters- Make sure you haven’t left them in the truck and that you can reach them in case of an emergency. Also allows your buddy to see where you have your line cutters located and reassures him they are useful and not completely rusted out etc.
  4. Check Lights – The first time my primary light went out during a cave dive I pulled out my backup only to find the battery was dead. I have also seen people get in the water with back-up lights that had no batteries in them. I have also seen people completely silt out a cave trying to retrieve a back-up light because they have it stowed out of reach and have not rehearsed retrieval.
  5. Check Reels/Spools – In an overhead environment forgetting a safety spool could mean your life. On a deep dive forgetting a line to shoot your lift bag could be catastrophic. On a complex multi-jump dive forgetting even one of your ten planned spools/reels can mean ruining the planned dive. Better to prevent these scenarios by checking your spools/reels as a team in an S-Drill.

Pulling out each spool/reel before each dive allows you to confirm you can reach it, that the clip is still there, the line is not frayed and that you have enough reels/spools for the planned dive.

  1. Check Lift Bags/Surface Markers – Have you ever dived somewhere with current in the open ocean? If so you should already have the diligence to confirm you have your SMBs during the S-Drill.
  2. Check Inflation/Deflation Mechanisms – What is the point of carrying a back-up inflation system if it does not work? When was the last time you checked yours? If it wasn’t at the beginning of the dive it has been too long.
  3. Check All Other Equipment Required For Dive
  4. Bubble Check – Bubbles are bad! They are weak points that are about to fail and ruin your day, possibly your life. Find them before the dive and fix them BEFORE the dive. Laziness is not an excuse! Even if you are an instructor and doing what you consider an easy dive. If as an instructor you have to stall the class to fix a bubble on your own kit then your students will see a good example. “Practice what you preach”

When performing the S-Drill in a 3 man team

Team member 1 performs the drill to team member 2 who then performs it to team member 3 who does it back to team member 2, ideally where team member 1 can see him as well.

Can this be done on a solo dive?

Yes, when teaching or solo diving I do this drill with myself. I have to be self-reliant. A CCR instructor is training a student to know what to look for. By the end of a course should be able to rely on the student to safely check the instructor but during the first dive maybe not. I suggest a polished sheet of stainless steel that can be used as a mirror for a self-bubble check. All other checks should still be performed to verify they are functioning correctly and to build the muscle memory of deploying them on every dive.

This may need to be modified depending on water conditions. For example could be done slightly deeper to avoid surface current, or on the steps with just feet in the water etc. Be prudent and only modify it to make it safer for the conditions.

This should not replace your pre-breathe nor pre-dive checks that happen before you even get into the water.

These may all seem like simple tasks but the first time you have to do any of these “simple tasks” in a blind, heavy current situation combined with the stress of an emergency you will be thanking me you practiced them at the beginning of every dive and that the muscle memory and confidence made it a “simple task” rather than a tragic diving accident.

Risk management is preventing an accident and being prepared for the accident that cannot be prevented. Always follow the rules you learned in your training. Plan your dive and dive your plan. Practice contingencies and diligently do your S-Drill before every dive. This will keep you alive.

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