Jan

8

WHY SHOULD I DIVE WITH A DIVE COMPUTER?

You just finished your Scuba Diver Course and your head is spinning with all the knowledge and skills you have learned. At the top of your list is purchasing what your instructor may have said was the most important piece of dive gear you could own – a dive computer. Your question is, “Why? What is so important about a personal dive computer (PDC) that I should have my own?”

Diverse on the Oriskany

Divers on the Oriskany

So, getting down to the basics means that there are three things you absolutely need to know during your dive: Where are you now? How long have you been there? How much longer can you stay? This translates into depth, elapsed dive time (EDT), and no decompression limit (NDL). All dive computers answer these questions, but ease of use, readability and additional dive information vary greatly between models.

Depth is one of the first things we set a limit on. Diving within the agreed upon depth limit, whether it be with the Divemaster, your dive buddy, or a solo dive, is the first decision a diver makes prior to the dive. Not sticking to your planned depth can be dangerous. The easiest way to monitor your depth is with the constant depth display on your PDC. An audible alarm is an important feature to alert you to any unplanned depth changes during the dive, including ascents. Your PDC will have an ascent rate indicator that allows you to insure you are ascending no faster than 30′ per minute. You won’t just descend to the bottom and swim around just off the sand. Many wrecks, reefs and rigs stick up off the bottom allowing you to do a 60′ dive on a rig in 200′ of water. But there aren’t any stop signs, so contantly being aware of your depth is important.

BUD
No decompression limit is one of 2 primary limitations when planning and conducting a dive profile. Some computers have audible alarms for this feature as well. Not following a good dive plan with regard to our profile (depth and time) could result in decompression illness. Going too deep, coming up too fast, and staying too long, greatly increases your risk for DCS. NDL takes your depths and times during each dive or repetitive dives and calculates how much longer you can safely stay at your current depth based on everything you’ve done up to this point. Breaking these rules could cause the loading of too much nitrogen resulting in a mandatory decompression stop. As a new diver, you want to avoid a deco stop at all costs. Your PDC can tell you when to move to a shallower depth, will continuously recalculate your NDL for the new depth. Not only does this keep you safely within your nitrogen limit, but it will significantly extend your dive times over the square profile associated with dive tables because it credits you back for times spent at shallower depths. Every single dive you do is a mutli-level dive.

The 2nd primary limitation is air consumption. You must continually monitor NDL and air consumption during the dive to be back on the surface with a safety reserve of air (usually 500 psi) and within the NDL. Your pressure gauge will give you your current tank pressure, but doesn’t give you any air time or consumption information. An air-integrated PDC gives you a digital display of tank pressure and because it has this extra piece of important information, can calculate the current depth and the rate you have been consuming air. So, simply it will tell you how much longer your air will last. The PDC then compares your remaining NDL and remaining air and tells you how much longer you can stay based on which is the limiting factor.

The easiest and safest computers are air-integrated with user settable audible alarms. This style lets you set alarms for minimum tank pressure, maximum depth, minimum NDL, ascent rate and many other parameters. Then if you approach or exceed any of these it will start beeping to get your attention and tell you what you need to do.

Even if you are primarily a traveling diver and rent equipment, most divers prefer to have their own computer. This way you are familiar with it’s use and display and don’t have to spend your bottom time studying the display to decipher it. Most important to American divers is that your personal computer gives you information in imperial form. Most of the world is metric and I can promise many frustrating minutes underwater mentally converting meters to feet and bar to psi!

Every dive is full of distraction from the moment our head goes underwater. Most of these distractions are the reason we are there: colorful fish and corals, dolphins, turtles, underwater cameras, spearguns, weightlessness, seashells, shipwrecks, pirate treasure & mermaids. But these fun distractions are constantly drawing your attention away from the tasks of monitoring your air return point, air ascent point, depth, duration and direction. A dive computer is the most important tool to assist in conducting a safe, relaxed and enjoyable dive.Digital Camera

For more answers on selecting your personal dive computer please consult a Gulf Coast Divers team member and schedule a FREE pool demo. dive with any computer.

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FREE Pool Dive Coupon

Try any dive computer in our 15′ in-door, heated pool

($20 value)

Gulf Coast Divers, 1284 Hutson Drive, Mobile, AL
(251) 342-2970

pool hours Mon.-Sat. 9:00am- 6:00pm

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