The Valve Drill (Shutdown) Explained

A free-flowing regulator or a leaking O-ring is loud, startling and fast. On doubles, it can drain gas you need for the rest of the dive. The valve drill is how you make the response automatic: reach the right valve, close the right thing, switch to the right regulator, and stay in trim the whole time.

What is a valve drill?

A valve drill is a practiced sequence for reaching, closing and reopening each of your cylinder valves underwater while you keep breathing, stay neutral and stay in position with your team.

It does three jobs:

1. Proves you can reach your valves. If you can't reach them in calm water, you won't in a real failure.
2. Builds the response to a gas failure. Shutting down the failed side and switching regulators becomes muscle memory.
3. Confirms your valves are fully open at the start of the dive.

It's a core skill in UTD's Essentials courses and Doubles training. Essentials of Tech requires a valve shutdown drill.

How does a valve drill work on backmount doubles?

Backmount doubles have three valves: a valve on each cylinder, called the right post and left post, and an isolator in the manifold between them.

• Right post: feeds the long-hose primary regulator and the wing inflator.
• Left post: feeds the necklace backup, the pressure gauge and, if you dive dry, the drysuit inflator.
• Isolator: joins the two cylinders. Closing it separates them, so a failure on one side can't drain the other.

The practice drill includes the right post, isolator and left post. Establish the working breathing supply and team support required by the trained sequence before manipulating a valve. Your instructor teaches the exact regulator changes, valve order, checks and signals for the rig; the practice sequence is not a substitute for diagnosing an actual failure.

How fast should it be?

UTD's Doubles standard asks for effective valve management: switching regulators, shutting down a valve in less than 15 seconds and reopening it in less than 15 seconds, and/or completing a full valve drill in 2 minutes.

Speed is the result, not the goal. A fast drill that makes you roll, drop your knees or drift up three feet isn't a good drill. Stay horizontal, keep your depth and keep the team in sight.

What are the nine valve failures?

UTD trains backmount divers for nine valve failure scenarios:

The source summarizes parts of the failure flowchart as "leak means isolate" and "leak and can't turn also isolate." Learn those cues within the complete diagnosis and team response for manifolded doubles. The leaking location, available breathing supply and valve condition matter; the nine scenarios are not nine identical shutdowns.

Failures 7 and 8 matter because the first guess is often wrong. The drill trains you to confirm which side is actually failing before you decide the problem is solved.

UTD's material ends with a caution worth repeating: other valves fail too, including drysuit inflation and stage and deco bottles. Don't limit your thinking to the nine.

What about a single tank?

A single tank usually has one valve feeding both regulators, so there's nothing to isolate. The single-tank check is about reach, function and the trained gas-failure response. Both regulators may share one valve and first stage, so changing second stages does not solve every failure, and closing that valve removes gas from both. Practice valve manipulation only within the procedure and backup arrangements taught by your instructor. UTD includes valve drills in all its Essentials courses, single tank or doubles.

What is a modified valve check?

Before the dive, teams run a short version: each diver reaches back, confirms each valve is operable and fully open, and checks the regulators breathe. It's quick, and it catches a valve that was turned off by mistake on the boat. See Pre-Dive Checks That Catch Real Problems.

How often should you practice?

Often enough that it stays fast and calm. Valve drills fade with time, especially if you dive a different rig between trips. Many teams build one into the start of training dives, with a teammate in position and ready to donate gas.

Practice the drill yourself once you've been taught it. In training, instructors also create surprise failures, with a safety plan and a gas source ready. Don't recreate those surprise scenarios on each other without that supervision.

Common valve drill mistakes

• Rolling or tipping forward to reach a valve. That's a fit or flexibility issue: adjust the harness and plate position with your instructor, and work on reach on land.
• Not checking the regulator before reopening a valve.
• Leaving the drill configuration uncertain. After a practice drill, verify the intended open valves and working regulators. In a real failure, a failed component may need to remain shut; do not reopen it just to copy the practice sequence.
• Doing it alone. The drill includes signaling your team and keeping them in position.
• Stopping at "fixed." After any real failure, the dive has changed. Reassess the gas plan with your team.

Learn it properly

The Doubles (Backmount or Sidemount) course trains valve management and the nine failures in depth. Essentials of Tech adds valve shutdowns to buoyancy, trim, propulsion and deco bottle handling. For how the drill fits into team diving, see Team Diving vs Buddy Diving.