Technically Speaking

Milestones in the Making

By Bill Nadeau

In less than a year from now every major training agency will offer technical level dive training. This will be a significant milestone in the history and evolution of sport diving. We knew it would happenwe just did not know when or how. Perhaps the answers lie in the reason why. Technical diving has become so much easier to participate in that it is now very appealing to the average diver. This is primarily due to the advancements in the diver training and dive equipment industriesthe result of incredible ingenuity and vision by key technical pioneers. When I compare the technical diving I did ten years ago to the way I dive today I am bewildered by the contrast. It is no wonder technical diving has grown in popularity. Yet you have to ask yourself is 'easier' a good thing? A year or so ago I may have said no, but when I look at the technology that makes technical diving easier today I tend to feel it is an unequivocal yes.

Let's begin with technical dive planning and preparation. The availability of gases and blending systems a decade ago was somewhat scarce and what did exist was expensive and moderately hazardous to use. Today a dive shop can get into a continuous flow nitrox blending system for under a thousand dollars and be pumping cheap nitrox within minutes of initial set-up. These systems are extremely safe, reliable and easy to use. I can remember paying up to $500 for oxygen analyzers and spending over a hundred dollars a sensor that needed replacing annually. Today there are oxygen analyzers one third of the price with sensors that utilize microwave sensing technology and do not require replacing.

The latest in blending technology is the Helium Analyzer created by Brad Gilmore. I had the good fortune to test a beta unit and after five months of trial I am in love with this gizmo. Small and compact, it operates by comparing the thermal conductivity of the sample gas (trimix or heliox) with that of a reference gas (air). A heated sensor is mounted so that it is exposed to the sample gas while the reference sensor is enclosed in a sealed compartment of the reference gas. Depending on the gas flowing through the sensor various reactions occur effecting conductivity. The temperature changes are monitored by electrical resistance changes in the sensing element. The results are interpreted and displayed on a digital display in a percentage format. Sounds complicated but this gem is easier to use than an oxygen analyzer and displays even greater accuracy. No calibration is necessary and the response time is less than 15 seconds. When incorporated into a continuous flow blending system the cost of fast and extremely accurate mixed gases is reduced to as little as 20% of its original price. I am now able to fill a set of twin 98s for about $20-25 dollars in less than 20 minutes with a completely homogenous 16/40 trimix. The Helium Analyzer takes all of the guess work out of trimix and heliox gas blending.

And if you thought mixed gas diving couldn't get any cheaper then you were wrong. Closed circuit rebreathers (CCR) have been around since the beginning but until very recently inexpensive reliable units were not available to the sport diver. Today a person can get into a CE approved CCR for about the same cost as setting up a set of deep diving twinsand the cost is still dropping. The unit I tested recently weighs a little more than a single tank set up, is compact and streamlined like a single tank and provides enough bottom gas and decompression gas for up to six hours of diving at any depth. Fed with oxygen and heliox from two small 20 cubic foot cylinders the unit automatically mixes the breathing gas and provided me with an optimal mix for whatever depth I am at.

With the partial pressure of oxygen fixed at the point I choose (usually around 1.3ata) I reduced my decompression obligation exponentially. At the end of the day my gas bill is about $5 for every hour I was breathing from the unit. In the past a diver had to design specialized tables from computer programs to take full advantage of the rebreather. There is a computer now available that can store up to ten mixed gases (nitrox and/or trimix) and has the option to run by fixed PO2s as opposed to fixed FO2s so that your decompression profile matches the exact gases within the rebreather. Very cool indeed.

These are just some of the toys that make our sport so incredible. We could also talk about scooters with 30 kilometre ranges, heads-up displays, underwater walkmans and powerful dive lights the size of a small baton. I can't wait 'till the new stuff comes out next year.