Friday, December 19, 2014

Redundant Breathing Systems... Confidence... the next step...

  Recreational diving and technical diving used to be a lot closer in the activities performed. Diving was done by a select few that were very well trained. They dove a lot and practiced their skills, including the emergency skills on a regular basis. One of the biggest myths in scuba diving is that you can run out of air underwater. As discussed in a previous blog, running out of air, unless done on purpose, seldom happens, and as I expressed, "you cannot run out of air." Please read the blog to find out why... Even so, basic scuba divers learn at least a couple of emergency techniques to deal with out of air situations. The emergency buoyant ascent and the emergency swimming ascent are two. A controlled emergency swimming ascent is part of every scuba diver's open water training. The question you have to ask yourself is, "do I remember how to do it?" Look up "s-drill."
As a NAUI dive instructor, I teach my students to be good dive buddies. Nonetheless, just because you are in the same ocean as your buddy, doesn't mean they will be in arms reach if you ever run out of air. Sharing air with a buddy is the prefered method to ascend safely to the surface. 

Most certification agencies don't encourage "solo diving." As a diver with technical experience, I understand that a technical dive is a solo dive. Technical divers plan accordinly and often follow decompression schedules that means they are required to stop at different depths. That being said, each diver on a technical dive site may not be able to exit the water together, so sharing air to the surface is problematic. Technical divers also plan for the worst case scenario and bring what they need to resolve those issues at depth. Recreational divers plan that in a worst case scenario, they've got to get to the surface.
Until you are ready to start your technical training, there are things that you can do to better manage your gas. You can follow a "rule of thirds." This might not be your best option unless you are diving with a very large cylinder. Most divers want to get the most time out of every dive and leaving a third of your gas in the cylinder usually means shorter dives. You can learn to manage your air consumption. Yes, your air consumption usually gets better over time, but how much air you are consuming on your dive is only part of gas management. The time to a site, time on a site, and the time to return to the shore are also part of it. Those takes time to learn and lots of dives to master.
There have been divers that jokingly have asked me if I was going to run out of air. They see the extra cylinder I regularly dive with and wonder what that's all about. When I do dives, I don't plan on running out of air, and while I have never had an equipment failure nor an out of air emergency, it could happen.

Divers carrying redundent breathing system can develop a level of confidence beyond emergency skills. I've seen it. I believe that the diver should be as confident even without the RBS. Look at it this way, if your dive buddy isn't near enough and there is an issue, you can be your own buddy and make your ascent safely and slowly, breathing all the while. 

If you don't dive with an RBS, have you been mentally rehearsing those skills and going over the maneuvers and procedures on a regular basis? One of my newest students demonstrated his confidence on a dive at Clear Lake. His regulator free flowed and he did exactly what he was supposed to. We shared air to the surface. He was totally cool during the whole procedure.

Likewise, one can't say that just because you have the equipment, that using it effectively is going to happen, either. Just like emergency skills, RBS skills need to be practiced. Ascents with and RBS have to be practiced. A few of my students have shared a confidence they didn't know before diving with their RBS. If they ever were on their own, they don't feel that the lack of a dive buddy is a danger. 

So, are you going to fork out a couple hundred extra dollars (minimum) for equipment you'll never use? The purpose of owning it is for emergency purposes, but owning it alone might not reduce any of the risks of diving. In fact, I was recently made aware of a change in policy requiring an RBS on a particular dive site. This dive site had a regular policy that an RBS was required in order to participate. Being an instructor myself, the dive guide felt comfortable sharing some of what they saw. Untrained in its use precipitated to several divers actually running out of air. While no injuries occurred, they could have. The common mistakes included: the diver starting the dive out on the smaller cylinder; switching to the redundant cylinder to extend bottom time; and in one instance, even completing the dive on the redundant cylinder because they interpreted, "returning to the surface with 500psi in the tank on their back," meaning that at 500psi the diver must switch to their redundant cylinder. 

If you want to learn more about the RBS and learn how to use it, let me teach you how.




Sunday, December 14, 2014

An SPG is not always an SPG...

When I teach my beginning open water scuba diving course, one of the things we talk about during the educational portion are the myths associated with scuba diving.
One of the biggest myths is that, "you can run out of air underwater." Here is why the perpetuation of this myth is unfounded. Unless it is your goal to actually breath all of the air out of the scuba cylinder, we will contend that no one wants to run out of air. As a NAUI Instructor, I promote diving with a buddy until the time comes that your training provides you with the requisites to attempt diving on your own. Solo diving will be left for another discussion.
So, what do I mean with that statement. Let's look at the SPG. The submersible pressure gauge is a tool used to aid the diver determine how much air is left in the cylinder. Believe it or not, there was a time when divers did not use pressure gauges. The scuba cylinder had a valve on it that when in the "off" position, left a little bit of air in the cylinder. Once the diver felt the resistance of getting low on air or ran out, they pulled a lever which opened the valve the rest of the way providing them the additional air required for an ascent. As you can imagine, the "J" valve fell out of favor. If the lever was in the "on" position all along and unbeknownst to the diver when they pulled the lever and there was no air, their only options were buddy breathing (one regulator, two divers) or an emergency ascent to the surface.
So, what do I teach my students. I teach them that, "you will never run out of air." When I say this to them, I ask them to tell me what they think that means. I usually get two interpretations. The first is that this diver, the one I teaching at this moment will not run out of air. As if they have a technique that makes it possible for them to survive underwater without needing to breath. Well, we know that can't happen. No one has that ability. Next, I hear that the diver believes that there is so much air in the scuba cylinder that it will never run out -- that it will never become empty. Well, as we know, that is not true either. It is possible for the cylinder to be breathed down to nothing and it is possible for all the air to escape from the cylinder (accidentally or on purpose).
This is what I teach. The SPG tells the diver how much gas is in the cylinder at that particular moment. Has anyone ever told you that all SPG's have a margin of error? Some more than others, but usually a few percentage points. Electronic pressure gauges are the same but the margin of error is higher. That's something to keep in mind. Also, just because the SPG reads 3,000psi doesn't mean there is 3,000psi in the cylinder. Most divers check the SPG when assembling their gear, but what about the moment they enter the water and after the cylinder cools? What about once you reach your desired depth or dive site? What would it mean if you looked at the SPG and it still read 3,000psi? What about 300psi? If you develop confidence as your dive career progresses, you should be able to look at it and determine that it is not working properly, tell your buddy, and swim safely and surely to the surface.
Mechanical failures are rare. Even when they do happen, what the diver does then can make the difference between life and death. Divers learn to never hold their breath, ascend slowly, and some even learn to relax well enough to extend bottom times and improve their buoyancy. Learning about air consumption rates, where you are, being ever present and aware of your equipment and your environment usually takes a little longer.

Saturday, December 13, 2014

NEW VS. USED SCUBA EQUIPMENT; Which should you buy?

NEW VS. USED SCUBA EQUIPMENT Which should you buy? How much is a 10 year old piece of scuba equipment worth today on eBay? Take the r...