Scuba Diving - 90 Meters Deep In a Swimming Pool

You probably think there are no swimming pools this deep. And you are one hundred percent correct. However I did a ninety meter deep dive in a four meter pool! We are talking serious technical scuba diving here, an extreme sport which attracts more and more people. People have been playing with various gasses as breathing mixtures for a long time, to make diving more safer in reaching greater depths. By mixing various gasses we can also reverse the effect. We are able to bring you under pressure in shallow depth, but we bring your head to a much greater depth. Gasses get toxic at certain pressures, and the following story will reveal how that feels.

Getting Narcotic While Scuba Diving in a Swimming Pool

A couple of weeks ago I went to France, to be part of an event for diving instructor trainers. The four days we’re extremely interesting, all sorts of new techniques where presented to us. And amongst us shared our diving and instructing stories from around the world. Tall stories as you may believe. The training agency offering this course, also educates people for the use of rebreathers and trimix or a combination of the two.

A rebreather is a mechanical or electronically controlled breathing apparatus, where the expired air travels through a scrubber unit to reduce or clean the carbon dioxide from the gas. The breathing gas is made breathable again. This is an ongoing process, and takes place in the breathing loop. When the oxygen content in the gas drops, and falls below the recommended limit, the unit will automatically put oxygen in the breathing loop.

Trimix and END

Trimix is a deep diving gas, containing oxygen, nitrogen and helium. When we dive on air (21% oxygen and 79% nitrogen) the gasses in air will give us limitations. The oxygen content will become toxic at depth. And the nitrogen content will give us decompression problems, and the narcotic effect of this gas at depth will reduce our ability to think and handle properly at depth, this effect is called nitrogen narcosis. It feels like being drunk and developing a heavy head.

To overcome these problems the amount of nitrogen in the gas is reduced by bringing a third gas to the mixture. Helium is a very pure gas which will have no effects when breathed by human beings. oxygen + nitrogen + helium is Trimix.

Depending on how much Helium we put in the mix the narcotic effect of the nitrogen in the mix will be reduced. The narcotic effect of the nitrogen is stated in END Equivalent Narcotic Depth, when compared to air. The END dictates where your head is. Your body might be at a depth of 70 meters, but because you breathe a trimix gas your head is only in 30 meters.

Diving with these gasses and mixture can be very dangerous, and can only .be done after extensive rigorous training.

Diving the Narcotic Gasses in the Swimming Pool

In Paris we had the opportunity to breathe a gas which had the opposite effect. Being in 4 meters of water with our heads at 90 meters. The four of us breathing from our normal scuba tanks filled with air, sat in a small square on the swimming pool floor. All of us holding hands like in a small marry-go-round In the middle of us was the cylinder with the magic potion equipped with a special breathing regulator. The person opposite of me was the first to go. He was having a good time; He was laughing and we could see his big smile behind the regulator in his mouth. We could read the fun he was having from his eyes behind the mask.

What an Unbelievable Diving Experience

Then it was my turn, I swapped my regulator for the special one. At first nothing happens, then after about a minute I felt a tingling in my fingertips, as if I where out in the cold walking into a warm room. I felt a tingling sensation all over my spinal court, I knew the gas was circulating around my body. I took a couple of deep breaths to speed up the process. The persons sitting next to me disappeared from my peripheral vision, the effects of tunnel vision where very clear. In front perfect focus, to the sides just a blur. I felt the same tingling in my feet, then a very warm feeling all over my spinal cord and shoulders again. All felt very pleasant. I could feel my head become lighter and lighter. To be honest, I knew I would not have been capable dealing with high demanding tasks anymore. I knew my name and where I was, but much more should not be asked of me. Lying on the swimming pool floor feeling happy was enough for me. I remember then when someone wanted to take the regulator away from me, I got very defensive. I handed the special regulator to the next person. I swopped back to my normal rig and after about two minutes my head was clear again. I nodded and it was time for number three.

Houston, We Have a Problem

Number three in our group, had a problem. The effects of the gas had a fast and much more immediate impact on this person. He lost control. He ripped the special regulator from his mouth and wanted to go straight to the surface. I immediately offered him my alternative air source. He refused and started crawling towards the surface obviously running out of air. I grabbed his chest strap and held him down. I stuffed my alternative air source in his mouth and after a few breaths he became calm again. I read from his eyes that he was okay. Slowly we ascended to the surface. His recovery was remarkable; but he could not remember what had happened a few seconds ago. He refused to believe it happened to him.

So, it is possible to do a deep dive in shallow waters, but needles to say it has to be done in a very controlled manner.

Diving on air to greater depths than 30 meters will have similar effects, the deeper you dive the more intoxicated you will become. Just stay within the safe diving limits. There is enough to see…

I was extremely thankful for the one organizing this rare opportunity. Merci Didier

If you have questions about the gas used, just email me.

We rather don’t reveal to the masses ;-)

frank.amptmeijer@hotmail.com