The Valve Drill Explained: Why Doubles Divers Practice Shutdowns

A free-flowing regulator is loud, startling and fast.

On doubles, it's also draining gas you need for the exit. Every second you spend finding the right valve is gas you don't get back.

That's what the valve drill is for. Not to look tidy at the start of a dive. To make the response automatic, so your hands know where to go while your head stays on the problem.

What is a valve drill?

A valve drill is practiced valve manipulation underwater while you keep breathing, stay neutral and stay in position with your team.

It does three jobs:

• It proves you can reach your valves. If you can't reach them in calm water, you won't in a real failure.
• It builds the response to a gas failure. Closing the right thing and changing to the right regulator becomes muscle memory.
• It 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.

How do the valves on doubles work?

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

• The right post feeds the long-hose primary regulator.
• The left post feeds the necklace backup.
• The isolator joins the two cylinders. Closing it separates them, so a failure on one side can't drain the other.

That's the whole point of a manifold. One failure shouldn't cost you all your gas.

Which valve you reach for, in which order, with which regulator in your mouth, depends on what failed and where. That diagnosis is what training is for. It's also why the drill is never just "close everything and open it again."

What about a single tank?

A single tank usually has one valve feeding both regulators, so there's nothing to isolate. The drill is about reach, feel and the response to a regulator problem. UTD includes valve drills in all its Essentials courses, single tank or doubles.

What does good look like?

Calm. Controlled. Still in trim.

Good valve work doesn't mean fast hands and a diver rolling forward to reach. It means reliable, repeatable valve manipulation while you keep control of your buoyancy, your trim, your breathing and your place in the team. Speed comes from that, not the other way around.

Where do valve drills go wrong?

• Rolling or tipping forward to reach a valve. That's usually fit or flexibility. Fix the rig with your instructor and work on reach on land.
• Doing it alone. The drill includes your team. They're in position and ready to donate gas.
• Stopping at "fixed." After any real failure, the dive has changed. Reassess the gas plan with the team.
• Never practicing after the course. Valve drills fade, especially if you change rigs between trips.

Here's the reality check.

The comfortable belief: I did my valve drill in class. I know where my valves are.

The truth: you know where they are when you're calm, warm and expecting it. Practice until that's true when you're not.

Learn it properly

Essentials of Tech builds valve work alongside buoyancy, trim, propulsion and bottle handling. The Doubles (Backmount or Sidemount) course trains valve management and failure diagnosis in depth. For the checks before every dive, see Pre-Dive Checks That Catch Real Problems.

Could you reach your left post right now, in full kit, without rolling?