How long a scuba diver can stay under water

There is a Scuba Diving Time Limit

There is a Scuba Diving Time Limit

Except for Michael Phelps, human beings are not created to spend most of their time in the water. We are a community of creatures who walk on dirt, and if you’re reading this right now, it is likely that you desire to extend your human limitations and experience to that which cannot be possible without the aid of scuba diving technology.


Sadly, even the distance and depth that technology has given to us cannot last for eternity. You buy a battery, it runs out. An Apple product gets released, YouTube asks, “Will it Blend?” Time destroys everything. This is evidenced by my Mum’s 8-pound cell phone rotting in some corner that rats call home. In scuba diving, time limits are also present. And our lack of functional gills tells us that managing our time underwater is the surviving equivalent as breathing on dry land.

The Technical Aspects

This part of the article deals with the scuba diver’s “mechanical gills”, or the scuba tank. Here, I am to explain how long a tank of compressed air will last so the scuba diver may know when to end his/her voyage. I researched for accuracy. Accuracy is good. But then, I stumbled upon this equation: 3000 psi / 14.7 psi = 204.08. For the sake of helpful simplicity, I have chosen not to go to mathematical territory and will try to be as accommodating as I can with the use of shallow words.

The most common and average scuba tanks hold about 80 cubic feet of air at a rated pressure of 3,000 psi. The average scuba diver will consume about a cubic foot of air every minute. So, that’s 80 cubic foot of air being used up at a rate of one cubic foot per minute. That would mean that the average tank will last about 80 minutes if used by the average diver. Aha! My high school diploma is proud of me.

Notice the overuse of the word, “Average” in the previous paragraph? Yeah, me too- I wrote it. My point is, the outcome of the numbers above is not absolute. The time a diver is allowed to stay underwater varies within the diver himself. If the scuba diver has the lungs of a young person like Justin Beiber, an average scuba tank will be more than enough. But, if you’re size is anywhere between Robert Downey Jr. and The Incredible Hulk, a larger tank is advised.

The Physical Aspects

Now that we’re shifting from the technical to the physical aspects of the scuba diver’s time limits, it would be safe to assume that we’d be able to breathe normal again by taking a step down intellectually, yes? No. As I was researching facts about this point of my article I came across with this:

Diving time limit formula

What the hell is it? Don’t ask. Please.

So where was I? Oh yeah. The human lungs are used to breathing oxygen. Our scuba tanks are not composed of pure oxygen. It is a mixture of gases. These gases aren’t dangerous. But when the scuba diver breathes too much of it underwater, he/she might contract ailments such as decompression sickness, nitrogen narcosis, oxygen toxicity. I don’t know what exactly they are, but the words, “sickness”, “narcosis”, and “toxicity” scare me.

Also, diving in shallow waters allows you to dive for a longer period of time because the shallower you dive, the less air is compressed. And remember, the human body is subject to hypothermia. This possibility is dependent on the choice of your dive spots. Go Scuba Diving in Palau this summer and you’ll be just fine. Try diving in Antarctica during the winter and you’ll be the homo sapien discovery after the next ice age.

Under Water Pressure in Scuba Diving

scuba diving pressure

scuba diving pressure

Have you ever seen that movie, Waterworld? I hope so, because I’m about to use that as an example. In Waterworld, Kevin Costner is without a single shred of diving equipment. Costner’s character jumps to the water and submerges to the deep parts of the ocean so fast; he could’ve saved half of the drowning passengers in Titanic.


An experienced scuba diver knows that Waterworld is deceitful in its presentation of people who descend to the oceans at great speed. If the vital element of pressure was taken into account in this movie, Costner’s character would’ve felt a painful, dying sensation crushing his body, ear drums, and the rest of his air cavities. His lungs would then collapse and life, as you know it, will end faster than Paris Hilton’s acting career.

A competent knowledge of pressure, and how to control it, is something that should be stamped into the scuba diver’s will to live. To secure this knowledge, it is in my own misfortune to tell you that the bloody wonders of Math must take part in this article for us to truly understand what underwater pressure is all about.

But before we numb ourselves with the necessary numbers, we have to discuss  some facts about underwater pressure. On land, we are under a great deal of air pressure. But that’s okay, because air is relatively light. When we dive in the ocean, we are under the influence of water pressure. We don’t need a scale to tell us that water is heavier than air. The ocean is a lot of water, and if the scuba diver wishes to reach the ocean depths, his body must have the ability to withstand all that water above him.

If you really want to master the act of controlling water pressure, well prepare to get a pen and paper cause we’re about to get arithmetical.    A cubic foot of air weighs approximately a pound and a half. Water, on the other hand, weighs just about 62.5 pounds per cubic foot. But the ocean is not composed of water, but sea water! So a cubic foot of sea water, thanks to salt, weighs an extra 1.5 pounds.

The more a scuba diver submerges himself underwater, the more the pressure increases. This type of pressure is called, “atmosphere of pressure.” The atmosphere of pressure is labeled as ATM, and is measured at 1 ATM at sea level. The ATM increases by 1 for every 33 feet a diver plunges into the ocean depths. So, if my ability to multiply still functions, 66 feet below sea level equals 2 ATM. It is also said that the diver can calculate the pressure’s effects to his body by using Boyle’s Law. My mathematical comprehension chooses not to torture itself by exploring this madness.

If the diver descends from sea level, he must not be too anxious to reach his destination- Because if the scuba diver hurries his descent, he might not live long enough to experience his ascent. Do not be sad, you don’t have to finger paddle yourself all the way down. You just have to be very careful in the first 15 feet of your dive. Be slow to dive, so your body can adjust to the pressure. During this time, you will feel a slight squeeze within you body. Once that feeling has disappeared, you’re good to go. But remember, during your way up to the surface, the same principles apply.

We don’t want any scuba divers going home with collapsed lungs or an exploded ear drum, or even worse, two exploded eardrums. So it is wise for the scuba diver not to let the preceding facts about pressure left neglected- Especially if you’re one of the guys who were responsible for making Waterworld.

The Best Diving Practices

As soon as man enters the deep blue sea, there is a change of everything. Walking is no longer our way of getting around. We float in style. Our access to unlimited oxygen is cut down to a tank-full. Instead of shopping for fish, some fish shop for us. Scuba diving is fun. But it’s only fun when you come out of the water the same way you came in. Below are few points on some diving practices that are advised to those who respect themselves as divers and respect the places that they dive in.


There are certain diving practices you have to follow

There are certain diving practices you have to follow

Secure the obvious

Aquaman, if you’re reading this: stay away! Everyone else is subject to the need of diving equipment. Diving shops can be tricky. If you’re new to scuba diving, try not to enter one on your own. If you have a friend who is an experienced diver, ask him/her to direct you to a competent diving shop that will not only sell to you your needs, but also cares for them.

When you’ve got enough equipment to survive a tsunami, go look for a good diving location. Ask yourself questions like, “What do I wanna see?” and “How do I get there?” How do you answer these questions? Do you literally have go beach hopping just so you can find a good diving spot? If your answer is yes, then my friend Google would be greatly insulted. I just said, “Google.” You’ll know what to do.

When in-depth

Now you’re in the water, and you feel like a scuba diving Boy Scout. You’ve got everything you need. Does this mean that you’re good for the day? Not quite. You need a sane and experienced “diving buddy”. If you’re going out with a group of friends that has been diving for awhile, then make sure you stick with them the entire time you dive.

But if you’re diving with a group of people you don’t know, it is crucial to find a dive buddy who will take care of you and knows what you don’t. Remember the movie, ‘Open Water’? Those two were not only diving buddies, but a couple. And they still ended up stranded alone in the ocean.

They might think you're a refrigerator

They might think you're a refrigerator

Creature Feature

Ah, yes- the ocean life. It is full of creatures big and small. Some are endangered, and some are dangerous. We need to take care of some of them, and we need to take care of ourselves from some of them. Observe all you want, but remember to keep you distance. Those who choose to take photos, choose your models carefully. A great white shark may be sensitive to flashes.

And yes, if I must say this, I’ll only say this once. Don’t feed them fishes. At first, it may sound safe and fun, but when you upgrade from bread crumbs to a Happy Meal, things may get ugly. If the unkind, bloodthirsty ones happened to notice that small “num-nums” keep popping out of you, they might get the idea that you’re a refrigerator.

Have fun diving with expeditionfleet! Enjoy collecting memories, but make sure there’s still room for common sense.

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