Descent/Safety Checks (S-drills, Bubble & Computer Check)

Descent checks are a great practice to get into doing on every dive. The descent check (aka s-drill, bubble, safety check) consists of 4 underwater checks. 3 before starting your dive and then a 4th if diving beyond 30m. The order of the checks should be discussed in the dive briefing along with the relevant signals, and what the course of action will be if there is a problem.

The start of the checks are normally indicated by the diver drawing a large S in front of them towards their buddy.

Check 1 – Bubble Check
Common Signal – I, Look, You, Bubbles
Your buddy will then either duck their head or twist slightly giving you full view of their 1st stage and hoses for a couple of seconds. You are then looking for bubbles coming from any part of his setup. Either your response would be ‘OK’ or ‘Something Wrong’. You then reverse the check with your buddy doing the check on you.

Check 2 – Alternative Air Source/Reg/Octopus semi deployment or full deployment.
Common Signal – I, You, Point at Reg, Switch
A full deployment is where you will release your alternate Reg to your buddy and allow them to take a couple of breaths before replacing the Reg. This is normally good to do with a new buddy or if you are diving with different kit configurations such as a long hose primary donation. For a semi deployment you demonstrate your alternative Reg can be deployed easily and will be free of any tangles and then restow. This check is not designed to replace your buddy checks, but to give you and your buddy chance to experience the donation underwater. As per the problem with tangles, you will see many divers do their buddy checks, then before going in the water, they add all their accessories.

Check 3 – Gauges Check
Common Signal – Look, Point to Wrist/Gauges
You are checking to make sure your computer is on and working as it should be as well as checking other gauges such as your gas. You should have agreed on a depth, so this gives you a chance to check your depth gauge is reading the correct depth. If they are working it is a simple ‘OK’ to your buddy if not then ‘Something Wrong’.

The checks are normally completed at a depth of around 5 meters. 5m is a good safe depth as it’s not deep and gives you a chance to sort any issues before descending. Now there are many dives and circumstances where it will not be possible to complete the checks at 5m. If this is the case the checks should be done as soon as possible. This could mean they are done at the bottom of the shot.

Check 4 – Narc Check
Common Signals – Flicking/Tapping the Cheek/Head
These checks should start between 25-30m (Depth Narcosis starts to kick in). If you are going beyond this depth, it’s good practice to do the check every additional 5 meters. Once you have reached you maximum depth, it is normally good practice to do a check after a couple of minutes. This is because they say Narcosis maxes out after this time (so if you stay at that depth you will be as Narc’d as you would be during the dive. As per the checks, there are a number of different ones you can do. 2 Common ones I see and use are;
Total 5 – This is where you put up x number of fingers, then your buddy puts up y number and the total of the 2 should equal 5. So if I put up 3 they put up 2.
Plus 1 – In this test works similar to ‘Total 5’ but your buddy instead puts up the next number in the sequence. So I put up 3, they put up 4.
It is good for your buddy to check back, and to use a different check if possible. As a buddy you are looking for 1) The correct test being carried out, 2) correct answer being given, 3) answer being given fairly quickly.
If anyone does any other checks, please share them.

As always I hope you have enjoyed the read.

G-SAV