A little beyond recreational depth

To go just a little bit deeper (in the 40 to 60m range), for a little bit longer comes at a high price. For a bottom time of about 20' we usually had twice as much decompression to do - and that on trimix with special deco-gasses, on air I don't even want to think about it. The decompression time would also increase dramatically if the bottom time was to be extended.

The actual price tag per trimix dive varies according to the amount of Helium in the bottom mix - which is in function of the target depth and the equivalent nitrogen depth - but averages at about 100 USD for shallow deep dives (in the above mentioned depth range), Helium not coming cheap (about 0.04 USD/liter) and having to pay for the instructor's or guide's as well!


As preparation to deeper dives, I did several dives with 3 stage tanks (one 10l bottom-gas and two 5.5l deco-gasses), all clipped to my left side, besides the twin set (2x12l) on my back. Quite a load on the surface and a bit of a hassle to get them all clipped onto the harness on a rocking boat, but surprisingly alright once in the water, except for some clanking tanks noise when frogkicking.

You need to be very careful when switching gasses. Breathing the wrong one at the wrong depth could be fatal. But so is crossing the street at the wrong moment. After those practice dives, having only one stage tank seems like a breeze.