You are out of the boat: the first ten seconds of a whitewater swim

Everybody swims. Instructors swim, expedition paddlers swim, people who have been on rivers for thirty years swim. The idea that a swim represents failure is one of the more dangerous ideas in the sport, because it makes people delay their exit until the situation is worse than it needed to be.

So: you are out of the boat. The water is loud, cold and moving faster than it looked from the bank. What happens in the next ten seconds determines most of the outcome.

Get on your back, feet downstream, feet up

This is the defensive swimming position and it is the default for a reason. On your back you can breathe. Feet downstream means you hit obstacles with your legs rather than your head. Feet near the surface — actively lifted, not dangling — keeps them out of the rocks on the riverbed.

The instinct is to face the direction of travel, because that is what land animals do. Fight it. Roll onto your back immediately and stay there until you have decided where you are going.

Never stand up

The single most important rule on moving water. If your foot goes into a gap between rocks and the current pushes your body downstream, your ankle becomes a hinge and the water holds your head under. This is foot entrapment, it happens in water that looks trivially shallow, and it is one of the most common ways people die on rivers.

The threshold is roughly knee-deep with any real current. If the water is moving, stay horizontal until you are genuinely in the shallows and the flow has stopped pushing you.

Breathe in the troughs

In a wave train you get air on the crest and water in the trough. Time it. Take a breath at the top and close your mouth on the way down. Panic breathing in a rapid is how people inhale water, and a person who has inhaled water stops making good decisions almost immediately.

Keep your paddle if it is easy. Let it go if it is not. Boats and paddles are replaceable and chasing them into a hazard is a well-documented way to get hurt.

Decide: passive or aggressive

Defensive swimming is for travelling through the rapid. But you cannot reach shore on your back with your feet downstream — that position has almost no propulsion. At some point you have to flip over and swim hard, front crawl, at an angle across the current toward a target you have already chosen.

Choosing the target first is what makes this work. Look for an eddy, a gravel bar, a friend with a throw bag. Then commit. Half-hearted swimming across a fast current achieves nothing; you get one or two decisive efforts before the cold takes your arms.

Hazards you swim differently for

Strainers — fallen trees, branches, anything water passes through and you do not. Do not go under. Swim aggressively toward it, get your head and shoulders up, and try to climb over. It is counterintuitive and it is the only thing that works.

Holes — recirculating water below a drop. If it is holding you, stop fighting the surface. The water leaving the hole is underneath. Tuck, swim down and downstream, and let the outflow take you. Ball up and go deep.

Undercut rock — water disappearing under a boulder with nothing coming out. Swim hard away from it, early, before you are close. This is the hazard that gives you the least time and the least warning.

The rope that is thrown to you

Grab it and roll onto your back with the rope over your shoulder, on the downstream side of your body. Do not wrap it around your hand or your wrist. Do not tie into anything. The person on the bank will pendulum you to shore and your only job is to hold on and keep breathing.

If you cannot catch the bag, do not chase it upstream. Look for the next one.

Practise this on purpose

Swim an easy rapid deliberately, on a warm day, with people watching. Feel how much slower you travel than you expected. Feel how hard it is to move across current. Learn how quickly your hands stop working in cold water.

A first swim in an emergency is a bad first swim. A twentieth swim in an emergency is a procedure.