The dive was completed without a rope, by means of visual references. I carried all gases myself. Before going for decompression the empty balloons with transport trimix were handed to awaiting support-diver Dina Artemchuk (Deco Procedures Diver, TDI).

Distribution of gases between balloons was the following:

·          Bottom mixture Tx 7/72 - aluminum twinset of 2 by 12 liters with the isolating manifold, 210 bars

·          Transport mixture №1 Tx 16/48 – 12-liter aluminum tank, 210 bars

·          Transport mixture №2 Tx 35/16 – 6-liter aluminum tank, 200 the bar

·          Decompression mixture №1 EAN 63 – 12-liter aluminum tank, 200 bars

·          Decompression mixture №2 EAN 67 - two 9-liter aluminum tank, 200 bars each

·          Oxygen – 6-liter aluminum tank, 110 bars.

In addition, I used 6-liter aluminum balloon with EAN 30 for approaching the diving point over the surface, it was returned to support-diver before the descending.

 

Used equipment:

·          BCD - dual chamber wing OMS, 60 lbs on the stiff aluminum back OMS

·          Regulators - Scubapro, the basic ones on the pair MK25AF + D400/S600 (respiration was provided from D400), additional ones on stages - MK2plus+R290, additionally purified ones for oxygen on stages with nitrox and oxygen.

·          Manometers - Scubapro compact, one of manometers - "tablet" from OMS, installed directly on the high pressure port of the first stage

·          Suit - individual sewing, the "Aquamarine" company, "wet", 5 mm + the heat insulant 5 mm + helmet.

·          Fins - Technisub Idea3

·          Decompression meters - three computers VR3, one - v2.1CXR, two – v3.03aC, installation of safety = 0

 

Diving profile (on the basis of real data from one of VR3 used in this dive)

 

 

Let’s make the profile analysis. For that, we will use “Dive Check” program. This is the new version of Mark Eliatt’s program “Decomparator”, which does not differ in mathematical algorithm, but contains additional graphic options.

 

Diving analysis.

 

 

 

It is evident from the given table that I ran a risk of counter diffusion at the moment of switching the gases, which is plotted in my method of mixtures selection.

The analysis of the middle diving phase deserves our special attention, it is the phase between micro-bubble and inter-phase stops. Here, the “Dive Check” indicates the risk of decompression illness, which, according to my feelings, was true (I experienced a certain discomfort in the elbow joint, which, however, rapidly passed off after timeout at 20 meters mark (the timeout is very visible on the diving profile chart). Based on the completed analysis we can make a conclusion about practicability of additional stops introduction during this diving phase (or slowdown of ascending speed). This problem, perhaps, is the weak place of VR3 algorithm, which processes this diving phase without proper consideration. In other words, having been exposed to risk of decompression illness, I conducted recompression in more “shallow” diving stage, and after that I had no comments about Dive Check’s profile.

By the way, please focus your attention on noticeable “hump” on the chart. It is obvious even on intuitional level that something is wrong here and it needs to be “smoothed”.

The real profile in the comparison with Dive Check’s recommended “ceiling”

 

 

 

Here you can clearly see everything that we discussed above – both exceeding the ceiling in the middle phase and “payment” for that in the beginning of active phase of decompression.

 

Organization of the dive.

Several words about the preliminary planning. Expected profile estimation was completed by means of Pro Planner and V-Planner programs. The calculation was performed for the depth of 210 meters; time on the bottom was equal to 10 seconds. The estimation of required gases quantity was completed by means of both mentioned planners and empirically, based on the experience of previous dives, in particular, of the dive to 192 meters. The selection of intermediate mixtures was performed in line with my own author’s procedure, which allows a reverse jump on nitrogen within the limits of 1,5 times.

The article about this dive was published in the DiveTek magazine.

 

 

After the dive:

 

 

 

VR3 computers used in this dive: