dive log

With Winter Coming, the weather is changing. Temperatures are dropping to the mid twenties, days at times are windy or even stormy, and the sea can then be choppy accordingly.

So, this week, we missed our intended dive site. Sometimes it’s difficult to judge the underwater currents from above, and we got carried away while sinking to the bottom. The plan was to visit a dive site at around 40 metres down, which means a long travel down, and while sinking you don’t see the ground, and thus have no idea that you’re carried away by a strong current, as you have no visual reference.

Then, when you’re down, and realise that you are at the wrong place, it’s too late. And if you think of it, if a current has blown you off your target point, you would need to swim against exactly that strong current to reach your intended spot. Meaning lots of effort, and consequently lots of air usage. If you even can do it. Those currents can be nasty.

The upside of the dive was that we went down to below 50 meters. Quite an experience. The travel down is amazing. In skydiver posture, around you just blue. You feel the water pressure rising, and rising, and rising. Equalising the pressure in the cavities in your head, by pinching your nose and applying pressure from your lungs, gets harder and harder. Thanks to the regulated air supply, breathing is always easy: the regulator increases the pressure of the air you breathe to exactly match the current water pressure, which squeezes your chest, hence breathing is like on the surface.

But the body feels the water pressure nonetheless. Time seems to slow down, but at the same time there is no time. At 50 metres, you can stay for about ten minutes, I’d say from the top of my head, without consulting the dive tables, before your body has accumulated too much nitrogen, which gets accumulated in your blood and body cells due to the high air pressure of six bar (six times the atmospheric pressure). Your mind slows down, literally. During dive training, there’s an interesting experiment, where you first solve some simple math on the surface. Then you dive, and repeat the math under water, and it takes you substantially longer.

I have always loved that state of mind, down there. We have a shipwreck here in front of the west coast, at just deeper than 40 metres, and I love that dive as well.

To make a long story short, I simply enjoyed to be down there, before we ascended. Slowly, with security stops, to let the nitrogen dissipate from the blood stream via the lungs, as otherwise nitrogen bubbles form in your veins, which would, hm, not be good.

The whole process of pressure-breathing and the related nitrogen accumulation and dissipation induces some tiredness in my body. While this is true for every dive, it’s amplified at these depths. I took a nap in the afternoon.

The picture shows the log of the dive on my (pretty battered) “dive computer”, a rather ancient term these days, where nearly every electronic gadget contains some microprocessor. Dive monitor might be a better term, as it monitors the accumulation of nitrogen in my body, counts down to remind me when to ascend, warns me if I go up too quickly, and shows at which depths to make decompression stops, and for how long. Nobody is using actual tables anymore for recreational diving, at least not directly, as the monitor of course has the tables stored and uses them do to its thing. When I learned to dive, I still used tables, though. There is no nitrogen probe connected to my body, the monitor uses the tables to estimate the nitrogen accumulation.

PS: for what it’s worth, it’s interesting that people ask me “…but did you get your money back for that failed dive?” No. That thought didn’t even cross my mind. For me, diving is to be there, not to achieve a promised, or planned, goal.