S-drill and valve drill before every dive: how your team simulates gas emergencies, operates valves blind, and communicates with fixed hand signals.
The honest answer first: in technical diving you're never really alone — and your team is part of your gear, not just nice company. Without a direct path up, a functioning team is often the only real plan B you have.
That's why every dive starts with an S-drill ("safety drill" or "sharing drill") right before entering the water: each diver practices live, once, how to donate gas to a partner in an emergency and how to receive gas from someone else. It's a dress rehearsal, not a formality — exactly the movement that has to work in seconds during a real emergency.
Add to that the valve drill: systematically checking, and if needed shutting down, individual cylinder valves on doubles to isolate a gas leak without losing the whole supply. This standardized sequence of movements ensures you react consistently and efficiently even under stress, instead of improvising.
Together, both turn a group of individual divers into a real team: everyone knows their role, everyone finds a partner's gear blind, and communication runs on fixed signals instead of chance.
Simulate a gas emergency right at the boat or shore: show your partner the out-of-air signal, hand over the long hose, swap roles. This one minute instantly reveals whether gear and reflexes truly work.
On doubles: reach blind over your shoulder to each valve, open and close it fully once, check the isolator in the middle. The goal is a fixed, identical sequence of movements that works even under stress.
Decide in advance who navigates, who tracks time and gas consumption, and who takes the lead in an emergency. Unclear roles cost precious seconds when it counts.
Use a small, fixed set of signals for the most common situations: gas switch, one third reached, problem, emergency, turn around. Fewer but unambiguous signals beat a large repertoire nobody remembers under stress.
Never lose sight (or, on a line, feel) of your partner. A team dive means constant mutual observation — gas level, body position, pace — not diving side by side without paying attention.
A team is only as strong as its least-trained member. An S-drill that "usually" works is too unreliable in a real emergency — the motion has to work under stress exactly as it does in calm training.
Better to abort a dive if the S-drill doesn't run cleanly at entry than to hope it will somehow work out underwater. That one minute at the start is the cheapest insurance you have. The same goes for the valve drill: if the motion still feels shaky, practice another season on land before you need it in a real overhead environment.
Practice the S-drill regularly outside real dives too, for example in a pool or dry on land. The more often the motion is repeated, the less thinking it needs in a real emergency.
A trick from experienced teams: regularly rotate who plays the "emergency diver" role in the S-drill. That way everyone on the team knows both sides of the exercise, not just their habitual role.
A dress rehearsal right before entering the water, where each diver practices live donating and receiving gas. It's the final check that gear and reflexes truly work for a real emergency.
To isolate a gas leak or a failed regulator on one side of doubles without losing the entire gas supply. The standardized motion ensures you react consistently under stress instead of improvising.
Because underwater communication otherwise gets too slow or ambiguous — especially under stress. A small, unambiguous set of signals for the most common cases is more reliable under pressure than a large but shaky repertoire.
Yes, every time. Familiarity doesn't replace a working procedure — precisely because routine tempts you to treat the drill as a formality, repeating it before every dive is what matters.
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