TRIMIX, that "new" gas becoming available
to divers made of Nitrogen, Oxygen and Helium,
is the gas we select for our deeper dives, whether they are wrecks,
open water or walls. Notice the quotation marks
around the word "new"? That is because Helium has been used for diving
operations since early this century ...... even way before SCUBA became
popular. It has been used since the first half of the century in
commercial, scientific and military operations
(just like Nitrox was) with an outstanding and enviable
safety record. Why is this so ?
Because of the increase in safety it provides the diver FAR
outweights any particular setback it might have. TRIMIX has
stopped being exclusive of extremely deep dives and has become
the choice for even those dives just within the recreational "limit".
We use TRIMIX for any dive deeper than 130 ft
(and some of us, even shallower than that).
First, and more importantly, it decreases inert gas narcosis to an acceptable level which is selected by the individual divers. This, by itself, more than suffices as a reason to dive it. A well-trained diver with a clear head is able to cope with most adversities that might be foreseen happening in a dive of this nature. On the contrary, the best trained diver would be a prime candidate for an accident (which at these depths has proven to be fatal) when they become mentally impaired by inert gas narcosis. How many HORROR stories have you heard from deep divers ...... if they can remember anything that happened at all?? With TRIMIX, the diver would select what (equivalent) nitrogen depth s/he wants, according to his/her own previous experience and ability to focus under such influence. So, a diver could be diving at 160 ft, but have the nitrogen level equivalent to, let's say, 100 ft ...... which is an acceptable level of impairement. Besides, using TRIMIX, they will be able to accomplish what their dive goals might have been and REMEMBER what they saw, did or didn't do at that depth. That clear head is CRITICAL when the margin for errors is as thin as the skin of your teeth.
Second, it now allows the diver to select his/her level of Oxygen partial pressure without having to trade with Nitrogen pressure. As depth increases we want to decrease our partial pressure of Oxygen to a safe level to avoid the dreaded Ox-Tox. With Nitrox, the only exchange is to increase the Nitrogen fraction, hence, its partial pressure (and associated narcosis). With TRIMIX, we are able to maintain a low PPO2 while maintaining a desired PPN2 by offsetting the lower Oxygen level with a higher Helium fraction. Now the diver has a controlled PPO2 AND a controlled PPN2 ...... which are two of the divers' main concerns for this kind of inmersions.
Third, the addition of a 'light" gas like Helium decreases the overall density of the breathing gas, making it easier to breathe at depth. When the gas density increases due to the increased pressure, the regulator efficiency becomes an important issue. Using a mixture which is less dense by the addition of Helium decreases gas viscocity, facilitating the breathing process which in turn decreases the bodily retention of another gas of concern, Carbon Dioxide (CO2). CO2 retention has been known to be a factor in increasing the propensity for Ox-Tox, Bends and Nitrogen Narcosis. So, by improving the breathing efficiency with the addition of Helium, we avoid CO2 buildup and hence, the probability of the mentioned maladies.
There are a few setbacks with the use of Helium in our mixes. The most important is that (depending on the dive time) it increases our Deco and starts with deeper stops (30 or 40 ft). Since most of the time we are doing some kind of Deco anyway, this addition of a few minutes might not be to much of a concern to us. But it does add to the overall dive plan since we must determine how much gas and at what percentages of Oxygen we are Decoing.
A second concern about the use of Helium is its cost. It increases the cost of the tankfill significantly. Unfortunatelly, there is little we can do about this except pay. But, when my life is at stake, I'd rather pay a little more and be MUCH safer than save a few dollars and increase my risks substantially. Would you save a dollar to rent a parachute without an emergency chute or would you pay extra for such a life-saving device?
Another item to consider is the fact that the training you get to be able to use TRIMIX is so intense and complete that you will use all the dive planning knowledge to do your regular simpler dives to the point of making them easier, more comfortable and safer. You will have a more complete picture of how your body performs and behaves under such pressures and conditions. You will have a more comprehensive knowledge of what gear is used for what type of dive and WHY. This new awareness will definitely sharpen your dive skills, specially in dive planning.
If you are looking for a solid TRIMIX education to be a better and safer diver, or upgrade your present NITROX level, Advance your knowledge while increasing your safety and enjoyment ..... Get better preparation and practice ..... Give the Accomplices a call for the next scheduled course or for one of our fantastic liveaboard trips ... SAFE ENJOYMENT WHILE YOU LEARN !!!