Feb

5

Neoprene is a man made rubber compound that when combined with correct fabric laminates provides an excellent material for wetsuits with stretch and durability.

Standard closed-cell neoprene incorporates millions of very small gas filled cells or “bubbles” that add inherent buoyancy and thermal insulation into the product. According to Boyle’s Law- one of the fundamental physical principles that must be understood by all divers- “The volume of gas is inversely proportional to the surrounding pressure”.

The effects of Boyle’s Law on the gas in the closed cells in the neoprene is that when ambient pressure increases on descent, the bubbles in the neoprene shrink due to compression and lose a percentage of the buoyancy and thermal insulation they provided at the surface. images

This isn’t an issue with wetsuits that are designed for surface water sports (skiing and surfing) because the suit isn’t subjected to any compression. For divers this means our suit that was sufficient on the surface where the suit is at it’s full thickness, doesn’t provide enough insulation to stay warm at depth.

To insure a comfortable dive, performance material base layers are utilized. These base layers provide additional thermal protection, but aren’t compressible so remain neutrally buoyant and don’t lose any thermal capabilities at depth. These base layers are flexible, light weight and can be worn in layers. Base layer materials such as LavaCore’s Polytherm can be worn as stand alone pieces, layered together or worn under a traditional neoprene wetsuit.

lavacoreBecause our gulf coast water temperature varies 25F throughout the year, you need to have a thermal system that allows you to vary what you wear depending on season, depth and area. Even when the surface is 85F in August, it can be 75F at depth and the freshwater springs stay 68F-72F all year.

For more information on designing a custom thermal system for your diving style, come by and talk to a system adviser at Gulf Coast Divers (251) 342-2970.

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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Sep

7

There is nothing more frustrating than struggling to enjoy yourself with a fogged mask underwater.  Most mask fogging is caused by warm humid air inside the mask meeting a lens surface cooled by water.  Warmer air is capable of holding more water vapor than cooler air.  Therefore, when air is cooled, a portion of its water vapor condenses into tiny liquid droplets, or “fog”.  Defog solutions prevent fogging by creating a thin, invisible film on the lens which creates a “sheeting effect” eliminating the formation of condensation droplets.

However, most defogs don’t work effectively on a new mask because of silicone leeched from the mask skirt and other factory residues left on the lens during the manufacturing process.  The lens on most new masks needs to be pre-cleaned with a mild abrasive to allow the defog to effectively change the surface tension of the tempered glass lens.  pr4

Sea Buff is the most effective pre-cleaner that I have come across.  Soft Scrub works pretty good, but has bleach in it, so your mask has a strong smell that is hard to get out.  More abrasive cleaners are likely to scratch the lens and less abrasive just don’t get the coating off.  I have seen people use a lighter to burn the coating off, but this is dangerous and a great way to ruin  a $100 mask before you even get it wet.  A bottle of Sea Buff  is $5.00 and will clean several masks.  Bonus use for the remainder of the bottle…it is a great slate cleaner, too!

Tips to diving fog free: Pre-clean new masks, follow the directions on your defog, store your mask in a hard case to protect it from dirt, salt and contaminants, put it away dry to prevent mold and algae build-up, avoid leaving your mask in the sun or on your head prior to a dive-the heat will cause a spike in the mask’s temperature which contributes to fogging, don’t exhale thru your nose-which increases the temperature on the inside of the mask.

Invest a few minutes to take care of your mask and it will reward you with clear dives.

Jan

29

What is mask squeeze?

Like the air spaces in your sinuses and ears, you must also equalize the air space in your mask as you descend. When you descend, failure to equalize, or add air to the air space in the mask, by exhaling through your nose can create unequal pressure between the mask air space and the vascular pressure within the blood vessels of the face. This can result in various degrees of facial barotrauma, or injury to the soft tissues of your face contained within the mask. Imagine your face in a suction cup. The soft tissues beneath the mask and especially around the eye swell (periorbital edema) and discolor, such as redness or bruising (ecchymosis).

What treatment do I need?

Unless you are experiencing eye pain or visual problems, there is no treatment for facial barotrauma except time. Because it is a bruise, your body will eventually reabsorb the effect of your mask squeeze. Your physician or an eye specialist should address eye pain or visual disturbances such as blurred vision or loss of part of the visual field immediately. These symptoms would be extremely rare in mask squeeze, however. The signs and symptoms of mask squeeze can take up to two weeks or more to resolve. Unfortunately, it is one of those conditions where you will probably look worse than you’d like before it gets better. Not only will blood and edema need to be reabsorbed, but it tends to be gravity-dependent – which means it will spread downward on your face. Before you heal, you may look like a red-eyed black-and-blue marked creature in a B-grade horror flick or a boxer that took at least two too many punches.

Who gets mask squeeze?

Mostly new divers get squeezed – they tend to be overwhelmed by all the skills they need to remember, such as buoyancy control and equalizing their ears and sinuses, all while being mesmerized by the mysteries of the sea. More experienced divers, however, are not immune to mask squeeze. They tend to have mask squeeze when they are concentrating on some new activity or focused in on a task which diverts their attention from clearing their mask. Changing to a new mask or to a low-volume mask may also lead to mask squeeze, because the diver may not be accustomed to when to add air. Finally, poor-fitting masks or other issues such as facial hair may lead to problems with equalizing.

How do you prevent mask squeeze from happening again?

The solution to preventing mask squeeze is to remember to keep your nasal passageways open during descent. By exhaling through your nose and using a properly fitted mask, you will minimize the risk of facial barotrauma. A mask should fit comfortably against your face and you should be able to achieve an appropriate seal by gently placing the mask on your face and inhaling through your nose. The mask should seal to your face and not fall off even without the mask strap in place. It is not unusual for a small amount of leakage to occur while diving, especially if you have facial hair. Exhaling through your nose and tilting your face towards the surface while cracking the lower seal of the mask will generally remove any unwanted water from your mask.

reprinted from www.diversalertnetwork.org