TIES THAT BIND

By Mark Young

A memory is what is left when something happens and does not completely unhappen.
~Edward de Bono

During a business trip to Florida I wound up near where I used to live, and stopped into a small airport where I kept a plane for a quite a while. I’m not quite sure, after nearly 20 years, why I decided to visit the flight center where I was based, but it called me back.

I’m guessing that the flight instructor behind the counter was in diapers when I was a customer there. We had a great conversation and some laughs, me sharing stories about how the place was, she telling how it is, and the old wooden flight center felt like home. Just the smell of the place summoned fond memories, and the experience was nicely nostalgic.

It's surprising how much memory is built around things unnoticed at the time. What from today will cause you to look back tomorrow and smile? You might just be in that place; you were probably introduced to this magazine at your local dive center and someday that store, the people you meet there and the experiences that you collect might mark a considerable time of your life. Most store owners and dive instructors are in this business to pass on to you what has such importance to them, so connecting you to diving, and a lot of great things to remember, should be natural. But sometimes even important things need a solid introduction to help them stick.

I mention this because of how the initial introduction to diving has changed. Not many years ago, people who learned to dive went through about 40 hours of face-to-face instruction. That amount of classroom and pool time allowed instructors and students to get to know one another, and a provided good conduit for the passion of diving to transfer. At some point, the industry decided that so much of a commitment to scheduled time was limiting participation, so they set out to shorten it with home study options to attract more people. As a result, some of today’s students may not spend as much time with an instructor outside of the pool sessions. But are they missing an important connection? Did we abbreviate ourselves out of the bonding that comes with spending time?

I wondered about that as I read this issue’s Instructor Tips column about the positive learning effects of instructor storytelling. It’s a reminder that much of learning happens outside the lines of a book or the glare of a screen. Observing that young flight instructor, I imagined how well she must be bonding her students to the excitement and the possibilities of aviation. I thought of her importance as a mentor, and her ability to inspire her students through the emotional desert of dry textural material.

I remember that learning to dive was an escape from my cubicled world; not a drag at all. Learning doesn’t just involve what you know; it inspires what you do with what you know. It is the emotional, not textural information that forms the strongest attachment. There is terrific benefit to being surrounded early on by the diving environment, the enthusiasm of a good instructor and sharing the excitement, anticipation and even some of the apprehension with other people who are learning too.

We in the industry want to connect you. It is important for you to help establish the connection too, especially if you don’t feel that it exists for you as it should. You don’t want to let this experience unhappen. Stop by your dive center to linger a while, and you might just find yourself stopping back in 20 years, and finding memories.

EDITORIAL September 2010: ENDLESS DIVING

By Mark Young

I know a couple who fell so hard for diving that they racked up close to 200 dives in just their first year. Living in South Florida made that easy. She would pick him up after a business trip, and head straight from the airport to a midnight dive. They dove the local charters; they bought their own boat which, since they were always under it, they renamed Two Down; they went east to the Bahamas, south to the Keys and into the Caribbean. They couldn’t get enough.

But there was more to get, like diving to the North. Any clue about Florida’s springs, just a few hours away, escaped them for years or they would have been there, next chance. He recalls that regretfully, like they were robbed.

Connect that to this. The nation’s highway system was built with materials that were mined along the way. The abandoned quarries filled with groundwater and many were reclaimed as recreation areas. Divers came along and populated the bottoms with things like airplanes of all sizes, helicopters, school buses, semitrailers, busses, boats and things you wouldn’t imagine. Some of the quarries are absolutely beautiful with a wide range of aquatic life, forests and sheer rock walls. Many have camping facilities and some even host outdoor music concerts. Their proximity to the highways that they built provides divers with easy access. As you would guess lots of quarry diving goes on in the United States.

Lots of other diving goes on too. Within our borders there is endless spring, lake, river and coastal diving. Heck, you can even dive in many of the nation’s aquariums, a theme park and in a major Las Vegas show. Local dive outings are an important business and social component for many of the nation’s dive centers.

The purpose of this editorial is to call your attention to a resource that we haven’t talked about much. It is the local diving component of our magazine and website. Many people who get certified limit their diving to foreign trips, and some of that is simply because they aren’t aware of the opportunities that are close by. It’s why we introduce two local diving spots in these pages each month. The couple that I talked about was also the inspiration for the “Diving USA: Dive Sites Across America” section at dtmag.com. That they were so nuts about diving but didn’t know about nearby dive sites raises the odds that lots of others don’t know about theirs either, especially newer divers.

For a number of years we have been compiling our local dive writings on the website, and now have hundreds of sites pinpointed on the map so that you can see the proximity and read about diving’s local opportunities. It is the most visited area of our website, and we encourage you to use it.

A great thing about diving is that it happens everywhere. Not many activities can match the experiences, the diversity, and the friendships that diving presents. Diving is literally available worldwide in such wide range. And whether you live in California or Arkansas, it is also close by.

Care to comment?

We add locations to the local diving site at http://www.dtmag.com/ monthly. If you come across a place that we haven't covered. or would like to tell others about a local site that you visit, post your comments below.

NO DUMB QUESTIONS, SEPTEMBER 2010: Diving After Flying, How Much is Too Much and Altitude Issues

By Alex Brylske

Q: Joe Plocinski wrote with a question that’s rarely considered concerning flying and diving. “I would like to know if there is a recommendation or rule of thumb for any ‘ground time’ interval between flying and making your first dive? During our certification class we were told that the recommended surface interval for flying after diving is 12 hours after a single dive, and 18 hours after repetitive/multiday diving. However, I do not recall hearing anything about diving after flying, or if there are any possible effects on the body. We will be vacationing in the Caribbean, arriving early afternoon and was wondering if it would be OK to get a dive in that day?”

A:You bring up an interesting point that’s rarely discussed, though given how common your experience is, it certainly should be addressed more often. Most informed divers assume that flying before diving poses no problem. In fact, you can make a logical argument that diving soon after a flight could impose a safety factor because you start the dive with less nitrogen in your tissues than you would if you were saturated at sea-level pressure. In theory, this might make sense. In practice, however, it might lead you to a recompression chamber.

The issue really isn’t the amount of nitrogen in your body, but rather the fact that a diver arriving at a dive resort after several hours of flying is not likely to be in his or her best shape. The stresses of the airplane cabin air, dehydration, restricted circulation from sitting in a confined position, and general fatigue from the journey are all factors that could place the diver under an increased — not decreased — risk for decompression illness. The best advice is to avoid diving until you are completely recovered and rested from the stress of flying to your favorite resort. Of course, that means there can be no hard-and-fast rule. Every individual is different, the actual stress of a flight depends on many factors, and only you know your body well enough to make the final decision of when it has recovered. Do many divers make their first dive just after unpacking their bags? Of course. Do some of them get the bends or incur other problems? Again, yes. Was their flight a factor in the outcome? No one knows. Perhaps a good compromise is that, if you do decide to dive immediately on arrival, make sure it’s a shallow, easy one.

Q: Deidre Levin had a question that I wish more divers considered. “I was on a live-aboard dive trip recently where most of us made between 20 and 25 dives during the five days we were aboard. One evening toward the end of the trip, our discussion centered on an issue that I’ve never seen addressed in any publication or discussed by any diving authority. But it seems like a simple and important matter. Can a diver do too much diving? I’m not talking about decompression sickness. Assuming that’s not an issue — the person feels perfectly fine — is there still a point when, like most things, there’s too much of a good thing?”

A: You have entered a very interesting realm of discussion, and you’re right; it’s rarely if ever addressed. Perhaps the reason almost no one ever talks about it is because we know so little about the long-term effects of diving in recreational divers.

It is, however, well documented that some commercial divers do suffer long-term effects. Hearing loss is one common ailment. However, another is a lesser-known condition called dysbaric osteonecrosis, literally, “bone death due to uneven pressure.” While to my knowledge it hasn’t been proven conclusively, many medical authorities blame this disorder on the extreme and continued conditions encountered by commercial divers, especially those who have a lot of deep-saturation experience. (By the way, it’s even been reported in sperm whales.)

The good news is that it’s believed that recreational divers spend far too little time underwater in their careers for this to be of any concern. However, there has been some evidence that dive professionals who spend extreme amounts of time at depth, such as divemasters and instructors, may be susceptible.

Still, my concern gets back to the issue that you dismissed: decompression. Even if someone does not manifest any symptoms of bends, we really don’t know what the cumulative effect may be. We do know that silent bubbles develop commonly in recreational divers, and that they most often resolve without any problem. But could they have a cumulative effect over many years or decades? Could age have any effect on this mechanism? Or, could more diving actually help build some form of immunity to bends? We just don’t know.

Personally, I’m a cautious person. And, probably like a lot of folks, I’ve gotten more so as I’ve gotten older. Now, in my diving, I almost never make more than two dives a day, and three is the absolute limit. I know that may sound unduly conservative — and I do have the advantage of diving just about any day of the week I care to — but that’s my decision. So, does the concept of too much of a good thing apply to diving? Probably, but we have no idea where that limit lies, and I personally don’t plan to provide any evidence.


Q: Dave Lewis sent in a question about altitude and diving. “I wonder about the oxygen content of compressed air in a scuba tank when it is filled at altitude where the lack of oxygen tires out hikers. Do dive centers at altitude enrich compressed air to normal levels?”

A: Your confusion is understandable given that hypoxia (low oxygen) is a common concern for anyone at high altitude. After all, who hasn’t watched a film about pilots or mountain climbers in which they didn’t see oxygen masks at the ready? As we’re reminded in the required announcement prior to every flight we’ve taken, supplemental oxygen is readily available in the event of loss of cabin pressure.

But let’s think more closely about this for a second. The concentration of oxygen in the atmosphere everywhere on the planet is 21 percent. (If you’re a stickler for accuracy it’s really 20.946 percent.) What’s more, that value holds true no matter where you are in the atmosphere, be it at the surface or about to step on the peak of Mount Everest. That means no matter where you fill a scuba tank, as long as it is somewhere on Earth, it will always contain 21 percent oxygen (assuming it’s not a nitrox fill, of course). So, if the oxygen fraction of air is always the same, where does all the concern over hypoxia come from?

The answer involves not pressure, but percentage. The physiological effect a gas has on our body depends not on the fraction of a gas within the mixture, but on the actual number of molecules we breathe. This is a function of the partial pressure of the gas in question within a gas mixture. An example will illustrate the point.

If you’re a nitrox diver you know that the oxygen partial pressure (ppO) at the surface, 1 atmosphere, is 0.21 ATA (reflecting its gas fraction, 0.21 x 1.0 = 0.21). At 2 atmospheres (33 feet [10 m]), where the pressure doubles, this increases to 0.42 ATA (0.21x 2.0 = 0.42). However, if you ascend in the atmosphere to a height of about five kilometers (16,400 feet), the pressure will halve. This means the oxygen partial pressure drops to 0.105 ATA (0.21 x 0.05 = 0.105). While we’d experience no problem whatsoever at the surface or at 33 feet [10 m], at altitude this low value is insufficient to maintain consciousness and we’d black out. Remember, however, that the percentage of oxygen in every case has not changed; it’s always 21 percent.

Q: Patti W. writes, “What should I use to rinse the inside of my buoyancy compensator (BC) after diving in salt water?”

A: First of all, it’s always good to give your gear a quick rinse in fresh water after an ocean dive, to rinse away the seawater. If you aren’t in the habit of rinsing your gear, you should be, because salt crystals that form on your gear when it dries can abrade surfaces, wear out threads and cause corrosion. A longer soaking at home after a dive trip — ideally in warm water — is also recommended.

Now, to the question of rinsing the inside of the BC, I’ve never actually used anything but fresh water.

Some divers use the eco-friendly product Simple Green® or similar mild detergents. There are also a few commercial products available just for rinsing scuba gear, so ask at your local dive center. Some have speculated that because a BC might be inflated orally, its interior should be disinfected periodically. So, a very mild bleach solution could be used for this purpose. In addition, some rebreather manufacturers offer nonbleaching disinfectant solutions, which are a better choice but, again, I think that good-old water should do the trick.