A year ago I was working in New Zealand. I was interested in what the local diving had to offer, so I signed up for a small trip off the local coast of Wellington. What happened on that trip turned out to be a valuable learning experience.

It was a cold morning when we pushed off from shore in a small fishing boat, six divers and two crew. I was a little nervous since I knew the water would be cold—it was winter there, after all. I wore an old, uncomfortable rented wetsuit. A farmer john that had seen more than his fair share of divers. Add in the unfamiliar equipment and all weights and cylinder measured in that odd system known as metric, and I was in an uncomfortable place to start a dive.

Once on the water the captain asked us each to introduce ourselves and briefly outline our experience. As we went around, I quickly realized I was the most unseasoned diver on the boat. Everyone else had hundreds, some thousands, of dives, most in the murky Wellington waters. Despite having recently completed my rescue diver certification, I was feeling a little intimidated when I had to announce my meager dive experience.

I was teamed up with Tom, one of the highly experienced divers, and a nice guy to boot. We did backrolls into the choppy water. With the new equipment and unfamiliar waters I was unsure of my weighting. When grabbing my weights in the shop, I had no idea how many to use. Not only were they in kilograms (although I knew the rough conversion), I had all new equipment and did not have a good starting point. I asked around what others were wearing, but I couldn’t use anyone remotely close to my size’s weights as a guide (for example, one diver had a steel plate in his BCD).

Time to descend. Instead of stopping Tom and doing a proper weight check, I didn’t want to look like an amateur and descended anyway. As soon as I slipped beneath the surface I knew I had made a mistake. Not a great way to start a dive.

Despite this ominous feeling, the dive went off without a hitch. I was cold and burning through air faster than Tom. I felt bad that I was limiting our dive time, but when my air got low, it was time to end the dive, but first, a safety stop at 5 meters.

During the safety stop I started to feel the effects of not being properly weighted. As my tank emptied, it became more buoyant, requiring more weight to stay underwater—weight that I didn’t have. Only a minute in and I was struggling to stay underwater. In fact, I was completely upside-down kicking to stay at safety stop depth. Unable to fight the buoyancy any more, I floated to the surface right before the end of the requisite three minutes, while my confused buddy watched from his safe depth.

In an attempt not to embarrass myself and look like an “amateur”, I ended up embarrassing myself far worse. Fortunately, my dive buddy was gracious and did not say anything as I found more weight for the next dive. I realized my stupid mistake and swore I would never put myself at risk again for the sake of looking more experienced. This time it wasn’t a big deal, but next time it may be in a more unforgiving environment.

No matter how little or how much you dive, there is nothing embarrassing about being safe and comfortable on all your dives. If your buddy or anyone else has a problem, then it is their problem, and you can rest assured that they’ll be the ones who end up looking inexperienced. No diver worth their salt would belittle you for being a safe and cautious scuba diver.

Photo by JennyHuang

Way back when, we gave a handful of tips for improving your air consumption. Today we have a few more.

• Be prepared. Have your equipment checked out and ready before you enter the water. Any problems will cost you in air. Also, know your dive site and bring appropriate equipment. If you know you won’t need the camera, for instance, leave it behind. It’ll improve your air consumption.
• Beware of free-flowing regulators. Some regulators tend to free-flow often. Be aware if you have one of these so you can catch it as soon as you enter the water. Free-flows drain air fast.
• Learn to kick properly. This is a topic for another article, but learning the proper kick technique will minimize wasted energy underwater.

Along with the previous list, choose one or two of these items to focus on each time you dive. You will be pleasantly surprised at how much air you’ll end dives with.

Photo by aa7ae

A Sydney newspaper reports that certain marine areas are overcrowded with scuba divers. These complaints come mainly from swimmers and anglers. The fishermen, in particular, are upset that divers scare off the catch of the day.

Sounds like its time for a sit-down to establish proper etiquette between the competing groups.

Visibility is one of the most subjective aspects of diving. Ask 10 people after a dive what they think the visibility was, and you’ll get 9 different answers. The last person will spend a half hour trying to guess.

Defining

People generally suck at estimating visibility (“viz”). Why is that? I think it comes down to a lack of common definition. I will attempt to define visibility in concrete terms.

The best place to start for this sort of thing is the dictionary. Webster’s defines visibility as

The distance at which something can be seen.

We’re getting closer, but what exactly is the “something” to be seen? I’ve heard a few options: the distance at which hand signals are no longer recognizable, the distance you can’t see a diver’s bubbles, and the distance at which you can’t distinguish an object. The first might be too strict for general use, but the last two start to get the point. Let’s define visibility as the distance at which an object cannot be discerned. The point at which you can’t tell for sure if that is a diver in the distance is the extent of the visibility.

Measuring

That was the easy part, now comes the hard part. How do we measure viz? Believe it or not, there is an established manner. It requires something called a Secchi disk. The disc is attached to a line and gradually moved from the measurer. The distance where the disk cannot be seen is recorded, with the length of the line being the visibility. Even more advanced methods with higher precision exist using photometers.

That’s nice for Jacques Cousteau, but not for Joe Diver who doesn’t have a Secchi disk on hand.

First of all, don’t feel bad. Viz is hard to guesstimate, but gets easier with experience. Even then, in general a range is a better indicator for estimating viz rather than a hard, fixed number. Try to get the lower end where things get blurry and the upper end where things can no longer be seen. As you get better with distances, this range will get smaller and the “true” viz will probably lie somewhere in between.

One rule with measuring viz for scuba: it measures horizontal distance. Vertical distance can be deceiving, as light from the surface increases visibility. However, it can be useful both for an upper bound on your range (vertical viz will always be higher than horizontal) and for estimating distances, since you always know your depth. Some, as a rule of thumb, define the viz as the vertical visibility (the depth where you can no longer see the surface) minus 3 m / 10 ft. Probably a good guideline, but useless in most of the tropics, where the viz always exceeds the dive depth.

Try to use anything you have to your advantage. Length of a wreck, for instance. You can find this out easily and use it to gauge distances more accurately.

Utilizing

I’ll let you in on a secret: it doesn’t really matter. Viz is cool for bragging (“We could easily see over 100 meters!”), but there aren’t too many practical reasons where an accurate number is necessary. There are exceptions, however. For instance, a photographer probably cares more so than others, since the equipment they take can depend on these numbers.

In general, ranges are fine, and even broad descriptions sufficing as well. A scale that goes something like amazing -> great -> good -> ok -> where’s my buddy? -> I can’t see my hand, is descriptive and covers most situations. Make an educated guess, compare to the guesses of others to refine your estimation abilities, but don’t get too hung up on the ever-elusive viz.

Need a gift for that special diver in your life? You may think diving-related gifts always break the bank, but here’s a list of mostly inexpensive ideas. Some of these can be extremely handy gadgets for a diver, even if she would never think to buy it for herself.

• Retractors, clips, etc. – These little guys can be immensely useful.
• Fancy dive log – Is your partner crazy about maintaining a meticulous log book? Maybe one of these is for him.
• Spring fin straps – These things are great for slipping open-heeled fins on and off easily.
• Mask cover – We’ve talked about how awesome these things are.
• Noisemakers – Get a pair of these, one for each of you. Check out your options at our article on noisemakers for scuba divers.
• Dive knife – Depending on where they dive, a knife could be useful. Nothing says I love you like weaponry.
• Dive bag – A very practical gift, since we all have to haul our luggage around somehow.
• Spare parts kit – Especially good for the tinkerer.
• Dive light – Not the cheapest gift, but good if your significant other enjoys night diving, and always has to rent a light.

What are your clever gift ideas for scuba divers?

Basic certification in most organizations permits diving to depths of 20m / 60ft. Secondary, advanced certification extends this depth to 40m / 130ft–the recreational diving limit. Past this and you enter the realm of technical diving. Where did this limit come from? There are two factors that led to this number:

• No-stop limits

  40 meters is about as deep as one can dive on air while still having somewhat of a bottom time (albeit less than 10 minutes, with a safety stop strongly recommended) before decompression stops are required. Even brief moments at depths beyond this without stops during ascent will almost certainly yield some form of decompression sickness.

• Nitrogen narcosis

  Technically nitrogen narcosis can take effect anywhere below 60 feet, but below 130 feet it reaches the point of being unmanageable without specialized training. The effects can still be strong even at 130ft, hence PADI generally recommends planning deep dives around 100 feet.

These are the two basic reasons behind the now-standard recreational dive limit.

Recently in Mexico, a woman gave me an account of a recent dive in Honduras. In this dive, the dive leader brought a bucket of chum (various fish parts). He would pull the fish parts out of the bucket and feed them to a swarm of sharks directly in front of the dive group. This gave the divers an up-close view of these amazing animals.

A similar story is told in a recent New York Times article. This time, the story takes place in Fiji. The author casually talks about the dive leader, who goes so far as to call himself “Papa”, feeding sharks as if they were his pets. The sharks know the ritual, gently taking “turns approaching the feeder in an orderly single file.”

What is wrong with this picture? Let me share several issues I have with this practice:

• It’s unnatural. This is the most common argument. Sharks are not pets. Feeding sharks on regular tourist schedules alters their natural feeding habits permanently. Even after chumming was prohibited in the Bahamas, sharks still regularly gather in those chum spots.

• It’s dangerous. The chum handler usually wears chain mail to protect her arm. What about everyone else on the dive? Divers are told to keep their arms close to their bodies, otherwise the sharks, who associate human arms with food, will go in for a quick bite. What about divers who happen to encounter one of these “domesticated” animals? What about those in the Bahamas who find one of these formerly fed sharks, a primitive animal that is expecting a free meal–from you!

• It’s not real. Encountering sharks under chumming conditions is basically a petting zoo. I think seeing one lone shark in its natural environment inspires more awe than 20 sharks waiting in line like its McDonald’s.

I’ve been debating in my mind whether I would ever participate in such a dive. For something like a great white cage dive the answer is easily, “no.” But what about something like a bull shark dive? After some thought, I feel the downsides of such an activity outweigh any desire I have to see a large gathering of sharks. I encourage readers to think through their positions and find where they stand.

How do you feel about chumming? Would you participate in such a dive? Do you have counter-arguments for why the practice is harmless, or even beneficial?

It’s never any fun when your dive gets cut short because your buddy’s air is low. It’s even less fun when you’re that buddy. This article compiles some handy tips on making your air last.

First off, keep in mind what it means to make your air last. You don’t necessarily need it to last an hour, all you need is to make it to your decompression limits. For instance, that’s just 40 minutes for a 66ft/20m dive (following the PADI recreational dive planner). Reaching some of these limits may not be possible, but it gives you a number to aim for.

Next, remember to track your air consumption in your log book. Even if you don’t take your log with you, it’s hard to keep all your start and end numbers in your head for a multi-dive day. Bring something to jot it down on, cause it’s impossible to judge your progress without some sort of written record.

So you’ve got a goal and a log of your progress, here’s some tips for getting those numbers up!

• Relax. Diving is fun. You should never be tense or wearing yourself out during a dive.
• Keep your breathing regular. It sounds obvious, but consistent breathing improves your air consumption. Try to catch yourself if you’re ever huffing away, and remind yourself to breathe slowly, counting your breath if necessary (in-2-3-4, out-2-3-4-5-6-…).
• Regular exercise. I could list all the benefits this has, but we’re interested in air consumption. Plain and simple, the more fit you are, the better your body utilizes oxygen, and the more it takes to get you winded.
• Quit smoking. If we ignore that it will most likely kill you, smoking also kills your air usage. Smoking trashes your lungs, which is terrible for air consumption.
• Yoga / Meditation. Diving is already compared to meditation under the sea. I have no doubt a big part of that is hearing your breathing through the regulator, making you mindful of your breath. Having a regular yoga and/or meditation practice teaches you mindful breathing. Who knows, it may make you enjoy your diving even more. (as if that were possible!)
• Use your snorkel at the surface. Whether you’re swimming to a buoy or just waiting for your buddy to get off the boat, switch to your snorkel. No need to burn through precious air when there’s plenty of it above the waves.
• Buoyancy control. Proper weighting keeps your body horizontal, reducing drag and slowing air consumption.

Use any or all of these tips as they apply to you to improve your air consumption and maximize that bottom time!

What are your favorite ways to improve air consumption?