Skip to main content

AQUATIC TACTICS: Safe Ascents & Dry-Land Drills by Mark Hatmaker


In prior articles in this series we have dealt exclusively with descending, preparing to descend, and how to manage comfortably while at depth. Now, let’s talk ascents as there are some dangers here as well, but, again, a marriage of science and indigenous diving wisdom renders these dangers negligible.

As we have discussed, when the human body descends to even shallow depths we experience great pressure changes, so great that even if we had a snorkel one meter long we would lack the muscular ability to intake a breath of air to survive.

At a depth of 10 meters [approximately 30 feet] we are already experiencing twice the pressure at the surface. The pressure at even greater depths is so extreme that deep sea fish brought to the surface often evert their viscera as the gas in their swim bladders expands and forces their guts out though their mouths.

Now, we are not deep-sea animals and seldom traipse along at such depths without extreme mechanical measures, but can we be subject to the same or similar dangers in shallow depths?

Indeed.

Let’s go back to that depth of 30 feet. If we were to take in a full lungful of air and then ascend without releasing any of that volume the air would expand and burst the lungs.

Even if we wisely do not surface with full lung-expansion we cannot assume a smaller volume is safe, we can still be subject to the dangers of the pressure change.

Even at partially filled capacity the lung-expansion as exterior pressure decreases on ascent can cause rupture of the air-sacs in the lungs allowing gases into the pleural cavity surrounding the lungs.

Even if the gases do not escape into the pleural cavity they can escape directly into the bloodstream where gravity, being gravity, will allow the lighter than blood-volume gases to rise through the throat into the cranium where the effect can be arterial blockage, i.e., an embolism, and often fatal.

These expanding gas injuries are called barotrauma.

A fully inflated lung and a quick ascent can burst that lung from a depth of only 2 meters.

We can damage our lungs at a depth of a mere six feet.

But…this rarely happens. Why?

Seldom do we fully inflate lungs before a dive, thus the wisdom of the ¾’s inflation advice in a prior article in this series.

And…indigenous divers naturally blow off gas as they ascend. This gradual trickling of air from the lungs even from great depths coupled with ascents made with speed allows the human being to ascend with safety.

In short, breathe out continually on the way up and you’re good to go.

Some indigenous peoples use a dry-land drill to both train lengthening breath-holding time and to inculcate ascending gas release. We can think of this as a form of “walking apnea.”

To give it a go—

·        Use one of the two breath-holding methods described in the earlier section.

·        Fill the lungs to ¾’s capacity.

·        Begin walking in a straight line at a slow pace.

·        At about the halfway point of your breath-holding ability, turn around and walk at the same pace back to your starting point.

·        On your return walk, slowly release the air in your lungs throughout.

By working this drill, you train your ability at breath-retention while in movement and not the usual artificial static-hold.

You also begin to learn your true make-or-break halfway point. If you take your breath before you return to your starting point, well, that is valuable feedback—you’re not ready for greater depth.

And you begin from the onset putting into practice the wisdom of gas release for safe ascent.

If you add any of the pressure-equalization tactics to the “walk-out” portion of the drill you will then have a very nice dry-land tactical drill-set ready to be worked before you even hit the water.
.

For more Old Schooltraining practices subscribe to this blog, the RAW Subscription Service and ourupcoming book Rough & Tumble Conditioning

Comments

Popular posts from this blog

Warrior Awareness Drills by Mark Hatmaker

THE Primary Factor in self-protection/self-defense is situational awareness. Keeping in mind that crime is, more often than not, a product of opportunity, if we take steps to reduce opportunity to as close to nil as we can manage we have gone a long way to rendering our physical tactical training needless [that’s a good thing.]
Yes, having defensive tactical skills in the back-pocket is a great ace to carry day-to-day but all the more useful to saving your life or the lives of loved ones is a honed awareness, a ready alertness to what is occurring around you every single day.
Here’s the problem, maintaining such awareness is a Tough job with a capital T as most of our daily lives are safe and mundane [also a good thing] and this very safety allows us to backslide in good awareness practices. Without daily danger-stressors we easily fall into default comfort mode.
A useful practice to return awareness/alertness to the fore is to gamify your awareness, that is, to use a series of specific…

Awareness Drill: The Top-Down Scan by Mark Hatmaker

American Indians, scouts, and indigenous trackers the world over have been observed to survey terrain/territory in the following manner.
A scan of the sky overhead, then towards the horizon, and then finally moving slowly towards the ground.
The reason being that outdoors, what is overhead-the clouds, flying birds, monkeys in trees, the perched jaguar—these overhead conditions change more rapidly than what is at ground level.
It has been observed by sociologists that Western man whether on a hike outdoors or in an urban environment seldom looks up from the ground or above eye-level. [I would wager that today, he seldom looks up from his phone.]
For the next week I suggest, whether indoors or out, we adopt this native tracker habit. As you step into each new environment [or familiar ones for that matter] scan from the top down.
I find that this grounds me in the awareness mindset. For example, I step into my local Wal-Mart [or an unfamiliar box store while travelling] starting at the top, t…

Resistance is Never Futile by Mark Hatmaker

Should you always fight back? Yes. “But what if…”


Over the course of many years teaching survival-based strategies and tactics the above-exchange has taken place more than a few times. The “but what if…” question is usually posed by well-meaning individuals who haven’t quite grasped the seriousness of physical violence. These are people whose own humanity, whose sense of civility is so strong that they are caught vacillating between fight or flight decisions. It is a shame that these good qualities can sometimes stand in the way of grasping the essential facts of just how dire the threat can be.


The “but what if…” is usually followed by any number of justifications or pie-in-the-sky hopeful mitigations. These “but what if…” objections are based on unfounded trust and an incorrect grasp of probability. The first objection, unfounded trust, is usually based on the following scenario.


Predator: Do what I say and I won’t hurt you.


Or, some other such promise to the victim.


Now, these sorts of …