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NUC AGM 2019 Postponed to Saturday 29th June

URGENT COMMUNICATION

Hi All,

Due to an overwhelming indication from the NUC members to change the NUC constitution and the responsibility of the Committee to present these proposed changes before the AGM; we have had to take the decision to POSTPONE the NUC AGM to 29 JUNE 2019

Please find below:

Please remember that only full members can propose changes to the Constitution.

On behalf of the committee I apologise for the inconvenience

I look forward to seeing you all at the NUC AGM – This is your chance to have your say and the members are taking advantage of this opportunity!

Daniel Mark Botha

Chairman Normalair Underwater Club

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Interesting Article | How Do Deep-Diving Cetaceans Avoid DCS?

Whales and dolphins have a special adaptation that allow them to explore the ocean’s depths.

 

Beaked whales can spend two hours beneath the surface. Dolphins descend down to 1,000 feet and ­routinely make as many as 20 dives in a row to 300 feet.

Good luck finding that type of profile on a dive table.

So, how do these mammals avoid getting hit with decompression sickness?

Special lung architecture helps protect them from the bends, according to a study by researchers at Woods Hole Oceanographic Institution and Spain’s Fundacion Oceanografic.

When air-breathing animals dive underwater, increasing pressure causes nitrogen bubbles to collect in the bloodstream and tissue. Ascending slowly allows nitrogen to return to the lungs and be exhaled. Ascend too fast, and nitrogen bubbles don’t have time to diffuse back into the lungs. Instead, they begin to expand in blood and tissues, causing pain and damage — DCS, or the bends.

Under deep-sea pressure, the lungs of cetaceans — whales, dolphins and porpoises — create two different regions, one filled with air and one collapsed. This creates a gradient in the amount of blood flow and gas exchange, taking advantage of differences in solubility of oxygen, carbon dioxide and nitrogen.

“These animals have the ability to change that rate,” says biologist Michael Moore, senior scientist at WHOI and a study co-author. “They can manipulate the gradient to favor conditions that transfer oxygen and carbon dioxide but not nitrogen, so as not to increase the risk of DCS. Blood flowing mainly through the compressed region allows absorption of some oxygen while minimizing or preventing the exchange of nitrogen.”

The scientists observed this phenomenon by inflating the lungs from different animals and putting them in a hyperbaric water chamber to simulate dives to different depths. “We compared dolphin, seal and pig lungs, and found dramatic differences,” says Moore. “Terrestrial mammals just don’t have the anatomical and functional adaptations that marine mammals do.”

Marine mammals are not completely immune to DCS, however. Scientists have detected decompression gas bubbles in seals and dolphins that drowned at depth in gill nets. Fourteen dead whales in a 2002 stranding event linked to U.S. Navy sonar exercises had gas bubbles in their tissues — a sign of DCS.

“We know that loud noises are stressful for marine animals,” says Moore. “It can cause a fight-or-flight response, increasing heart rate and vascular dilation. That messes with this protective mechanism — with the way the animal has programmed its dive — and increases absorption of nitrogen in blood.”

The research doesn’t explain why DCS might cause a cetacean to beach, says co-author Andreas Fahlman.

“But just knowing that stress can cause failure of this adaptation means we might find ways to mitigate it,” he says. “The solution could be as simple as starting sonar at low levels so the animals don’t freak out, then increasing levels gradually to give them a chance to move away.”

 

 

Article by Shane Gross,

REF: https://www.scubadiving.com/how-do-deep-diving-cetaceans-avoid-dcs 

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Interesting Article | Don’t let your ears ruin your dives

A great article by DAN South Africa and DiveIN Magazine on the full guide to ear and diving

 

Don’t let your ears ruin your dives

You’ve just started your first dive of the day. Everything is going great! You pinch your nose and blow to equalize your ears, but nothing happens. You try again, but same issue.

Your ears starts to hurt…you try again but it’s the same.

So what now?

Accent and end the dive or push on?

No!
It’s time to learn how to equalise the right way!

According to a survey* we did, we discovered that:

  • 89% of divers doesn’t equalize the correct way
  • 29% of divers had to stay out of the water for weeks or months due to problems caused by equalizing
  • 6.3% of divers have gotten permanent ear damage due to problems with equalizing

That’s right, you might be Equalising the wrong way!

The real issue is that the way most of us was thought to equalise, and the method that usually works, is the wrong way to do it.

It’s the Valsalva Maneuver: Pinch your nostrils and blow through your nose. The resulting overpressure in your throat usually forces air up your Eustachian tubes.

How come it works if it’s the wrong way? It works perfectly fine as long as you keep the tubes open ahead of the pressure changes. However, if you do not equalize early or often enough, the pressure differential can force the soft tissues together, closing the ends of the tubes. Forcing air against these soft tissues just locks them shut.

5 Better ways to Equalize

Toynbee Maneuver – Pinch Your Nose and Swallow
With your nostrils pinched or blocked against your mask skirt, swallow. Swallowing pulls open your Eustachian tubes while the movement of your tongue, with your nose closed, compresses air against them.

Lowry Technique – Pinch Your Nose, Blow and Swallow
A combination of Valsalva and Toynbee: while closing your nostrils, blow and swallow at the same time.

Edmonds Technique – Pinch Your Nose and Blow and Push Your Jaw Forward
While tensing the soft palate (the soft tissue at the back of the roof of your mouth) and throat muscles and pushing the jaw forward and down, do a Valsalva maneuver.

Frenzel Maneuver – Pinch Your Nose and Make the Sound of the Letter “K”
Close your nostrils, and close the back of your throat as if straining to lift a weight. Then make the sound of the letter “K.” This forces the back of your tongue upward, compressing air against the openings of your Eustachian tubes.

Voluntary Tubal Opening – Tense Your Throat and Push Your Jaw Forward
Tense the muscles of the soft palate and the throat while pushing the jaw forward and down as if starting to yawn. These muscles pull the Eustachian tubes open. This requires a lot of practice, but some divers can learn to control those muscles and hold their tubes open for continuous equalization.

When to Equalize
Sooner, and more often, than you might think. Most recommend equalizing every two feet (.6 meters) of descent, but often that’s too late. At a fairly slow descent rate of 60 ft (18.288 m) per minute, that’s an equalization every two seconds. Many divers descend much faster and should be equalizing constantly.

The good news: as you go deeper, you’ll have to equalize less often!

10 Quick tips to make equalizing easier

Listen for the “pop”
Before you even board the boat, make sure that when you swallow you hear a “pop” or “click” in both ears. This tells you both Eustachian tubes are open.

Start early
Several hours before your dive, begin gently equalizing your ears every few minutes. “This has great value and is said to help reduce the chances of a block early on descent,” says Dr. Ernest S. Campbell, webmaster of “Diving Medicine Online.” “Chewing gum between dives seems to help,” adds Dr. Campbell.

Equalize at the surface
“Pre-pressurizing” at the surface helps get you past the critical first few feet of descent, where you’re often busy with dumping your BCD and clearing your mask. It may also inflate your Eustachian tubes so they are slightly bigger. The guide here is to pre-pressurize only if it seems to help you and to pressurize gently.

Descend feet first
Air tends to rise up your Eustachian tubes, and fluid-like mucus tends to drain downward. Studies have shown a Valsalva maneuver requires 50 percent more force when you’re in a head-down position than head-up.

Look up
Extending your neck tends to open your Eustachian tubes.

Use a descent line
Pulling yourself down an anchor or mooring line helps control your descent rate  more accurately. Without a line, your descent rate will probably accelerate much more than you realize. A line also helps you stop your descent quickly if you feel pressure, before barotrauma has a chance to occur.

Stay ahead
Equalize often, trying to maintain a slight positive pressure in your middle ears.

Stop if it hurts
Don’t try to push through pain. Your Eustachian tubes are probably locked shut by pressure differential, and the only result will be barotrauma. If your ears begin to hurt, ascend a few feet and try equalizing again.

Avoid tobacco and alcohol
Both tobacco smoke and alcohol irritate your mucus membranes, promoting more mucus that can block your Eustachian tubes.

Keep your mask clear
Water up your nose can irritate your mucus membranes, which then produce more of the stuff that clogs.

 

REFERENCE: https://www.divein.com/articles/diving-ears/ 

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Interesting Article | Tips on shore entry and exit while spearfishing

Much of the south African coastline is rugged and exposed to wind, swell and surf from both the Indian and Atlantic ocean and to reach the reefs swimming in from shore one has to negotiate these elements.

 Our coast does not have the pristine conditions found in the tropics or meditteranean and really calm settled seas are found only for a few days of the year mainly at the beginning of winter around May and in summer around January/February. for the rest it is constant surf unless in the sheltered bays or peninsulas along the western cape side.

Physical fitness and good light weight equipment are both pre requisites especially a good pair of fins when entering through the surf line and exiting after the duration of a dive.

Generally the swell and wave size averages 1,2 -1,5 m along our eastern shores but peaks from 2 -4 m in rough seas and these type of conditions are definitely not recommended for beginners. In fact anything over 2m is downright dangerous.

For guys new to the sport of spearfishing or cray-fishing here are some important things and safety factors to bear in mind when doing an entry and exit along the shoreline :

  • Preferably dive with a buddy and learn an area from a more experienced spearo or cray diver as well as as much information as you can from a local as to where the reefs are in proximity to the shore line and best and most safe spot for your entry and exit.(In reasonable conditions)
  • Have a plan for your dive taking into account you may have to exit at an alternative point if conditions change during the duration of your dive which they often unexpectedly do (Current may change, tide ,wind etc)
  • Pick a spot with the easiest point of entry for swimming out like an outgoing rip or sandy beach with not too many rocks to negotiate on the way out and likewise your point of exit which could be the same spot but preferably an area of sandy beach close to your entry point or within a few hundred meters of it. A rocky shoreline can present a hazard so look for a bay both north and south where you will possibly have to swim in.
  • Windguru gives a reasonably accurate prediction a few days ahead in swell or surf size.
  • Take the time to watch the sea and wave movement for a good few minutes before you decide to enter which you and your buddy should agree on, If your gut feel tells you “No’’ then rather choose a day when you feel more comfortable or a calmer sea.
  • Surf usually appears smaller than what it is from a distance and comes in sets (With calms in between) for this reason it is important to asses it properly.
  • I usually consider the swimming out through surf more difficult than the return swim in.
  • Wear fin guards, it is easy to lose an expensive fin or both should you get dumped in the surf zone- the rubber Y straps are still the best and reasonably inexpensive when compared to a set of good long bladed fins which these days are seldom under R1000.
  • Be aware of where your buddy is when swimming out and try to time your entry both together- this way you are less likely to be separated and also link up once you are behind the backline before proceeding out deeper.
  • Keep your bouy line of the speargun as short as possible on both the swim out and back in, it can be wrapped around the speargun or tied in a looped bunch secured at both ends – this lessens the drag on the bouy which bears the brunt of the incoming breakers as you dive beneath them, similarly swimming in and especially with a few fish on the bouy against (If you happen to encounter) an outgoing rip will create additional drag if the bouy is too far behind you.

Once you have completed your dive behind the surf zone or a reef a few hundred meters out and have decided to swim in, confirm with your buddy, swim up just before the backline, wrap up excess bouy line, rest up for a few minutes, let the bigger swells pass ahead of you and tuck in behind a wave aiming at your desired point of exit on the beach. Look over your shoulder now and again, duck a bigger breaker or two if they come in behind you and let the smaller foamies assist in pushing you in whilst still swimming. Look out for rocks as you approach the shallows and walk backwards up the beach facing the sea.

Should you find yourself in a dire situation either swimming out or in- never panic and the weightbelt should be ditched in an emergency where the wetsuit will provide adequate buoyancy and also acts as a ‘life vest’

These are a few general important pointers.

Safe Diving!

 

Article kindly provided by Darrell Hattingh

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Interesting Article | Tips to Conserve Air while Diving

 

‘the best way to observe a fish is to become a fish’  Jacques Cousteau

  1. Keep warm. Make sure that you have the correct thermal protection for the planned dive. Getting cold increases your metabolic rate, consuming more oxygen.
  2. Go slow. Only move if you need to! Sudden jerky movements and increased speed underwater all consume more oxygen. Don’t chase sea life! Don’t try to gather everyone in the dive group to show them what you saw. Don’t fight the current. Use any surge to your advantage.
  3. The more efficient your fins are, the less energy you expend. Get the right fins for you!
  4. Do not use your arms. Try to use your arms as little as possible.
  5. Trim up. Check your weight distribution so that you do not need to constantly compensate for being off-balance.
  6. Streamline your gear to reduce water resistance.
  7. Orally inflate your BCD. If your weighting is correct you will require less air in your bcd, thus reducing your head-on profile.
  8. Swim horizontally. Get your buoyancy correct.
  9. Control your breathing. Breathe deeply. Inhale for 5-7 secs, exhale for 6-8 secs. With practice you will do it automatically without having to count. Otherwise, hum a slow tune to yourself!
  10. Breathing pause. Pause for a second or two at the end of inspiration to allow more oxygen absorption. Usually we pause at the end of expiration, so this takes a little practice. This does not mean ‘skip breathing’.
  11. Restrict air flow. Some DV’s can be set. Otherwise inhale with your tongue against the roof of your mouth creating a natural restriction.
  12. Dive shallower
  13. Use your snorkel if you need to swim on the surface.
  14. Reduce air leaks. Service your gear regularly.
  15. Practice. Dive, dive, dive! The more comfortable you are in the water, the more relaxed you will become, the better your air consumption will be.

 

If you have any other tips to add, please do so!

 

Author: Dr Mark k. Botha

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Interest Article | Fun facts about Scuba Diving

Scuba diving is safe

This isn’t so much one of our fun scuba diving facts as just a fact, and one that’s worth repeating to anyone interested in the sport. According to Divers Alert Network (DAN), the 2010 fatality rate in scuba diving was one death for every 211,864 dives. Compare that to one death in 126,626 for marathon runners. In fact, driving a car, playing soccer, golf and skydiving all cause significantly more deaths, in relation to number of participants, than scuba diving.

Sharks are safer than coconuts

Shark encounters are one of the main fears people have when taking up, or thinking of trying, scuba diving. Many divers dream of seeing sharks while diving, but for some, it’s still a cause of concern. So it’s worth reminding them that coconuts present a far greater danger than sharks during a tropical vacation. Say what? Well, roughly 150 people are killed every year by falling coconuts — they are really, really heavy and fall from great heights — compared to around 10 yearly fatalities from shark attacks.

A broken toe is a very common scuba-diving injury

While most reports on diving injuries site various barotraumatic injuries as the most common, this is largely due to broken toes either going unreported or unrecognized as a diving-related injury. But according to ER staff I’ve spoken to, this is a very common injury, perhaps even the most common. Why? Combine heavy objects, such as tanks and lead weights, with a lot of barefoot people and wet, slippery hands, and I’m sure you get the picture. Another reason to exercise caution when carrying tanks to and from the gear-up site.

How deep can you go?

Divers often ask how deep they can go, and the cheeky answer is “all the way to the bottom, but we try to stop around 130 feet.” In fact, we can go a lot deeper than that. The world record for a deep dive on a standard, open-circuit scuba system was 1,044 feet, by South African diver Nuno Gomes, in 2005 off of Dahab, Egypt. The dive took 12 hours and 20 minutes, of which only 14 minutes were used on the descent. Gomes also holds the record for deepest cave dive, at 927 feet. The deepest any human has ever been is to the bottom of the Mariana Trench in the Pacific, at nearly seven miles. Using mini-subs, only three people have ever attained this depth, Jacques Picard and Don Walsh in 1960, and in 2012, movie director James Cameron.

Most time spent on the Titanic

Speaking of Cameron, the longest time spent on the RMS Titanic after its completion was not by a passenger, crew, or even the captain. Rather, it was by the director himself, who made a total of 33 dives there, totaling 462 hours, as research for his films about the ship. In an interview, Cameron jokingly stated that he made the movie to have an excuse to dive the wreck. Obviously this isn’t an everyday dive.

How long can you stay underwater?

This record is a bit more complex, as records differ between salt or fresh water, cold or warm, confined waters or open sea, and the type of equipment. But the longest warm-water dive on a standard, open-circuit scuba system was done in the summer of 2013, when a British man, Sean McGahern, spent 49 hours and 56 minutes on the bottom of the Mediterranean off Malta. He kept himself entertained by cleaning the seabed of debris — I guess housework can act as a distraction if the alternative is looking at a the ocean floor for almost 50 hours.

 

 

Article from https://scubadiverlife.com

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Info Article | Buoyancy and the evolution of the BCD

Scuba divers world wide are familiar with the BCD – Buoyancy Control Device, this is the “jacket type” piece of dive gear that assists the divers with 2 valuable functions: 

Maintaining proper buoyancy control and having a device to attach the tank to the diver.

Buoyancy control is very important to divers as it allows proper horizontal or depth control while diving, allowing divers to dive safely (for equalisation), comfortably and avoid crashing into underwater plants, topography and structures (yes, conservation and self preservation are important); in other words, buoyancy control is as essential to diving as “balancing” is to riding a bicycle.

If you’ve  been diving less than 20 years you are probably most familiar with the “modern  jacket type” bcd). The main parts of the bcd are: adjustable shoulder straps, the BPI (or basic power inflator), cummerband, dump valves, tank band/strap and utlity pockets. The adjustable shoulder straps and cummerband ensure correct fit for comfort. The BPI allows the diver to add or subtract air for the correct buoyancy oreintation it is basically a puck or box with a “put air in” button and a “let air out” button; most bpi’s also have a mouthpiece allowing the diver to orally inflate the bcd.  

Let’s take a look and see how the bcd evolved

Way back when (> 25 yrs ago) there was a buoyancy device that divers called the horse collar: basially a round tube with a hole for the diver’s head, an inflation device, a couple of straps and maybe a utility pocket in the front – no comfortable cummerband or adjustable shoulder straps. To attach the tank, an additional device called a “backpack” was necessary. It consisted of a rigid plastic “plate” a tank band and shoulder straps.  Divers strapped on the back plate with tank and then donned the horse collar. A mission, yes,  but this was state of the art way back when (i.e. before the internet or cell phones)!

Moving along the development curve, Scuba Pro came up with the STAB (stabilising) JACKET. Really neat! It combined the functions of the horse collar and backpack into a single unit with a comfortable cummerband, tank strap and air chambers in the shoulder straps, and also utility pockets. A really comfortable unit, however not very popular in SA as there are no adjustments to the fixed shoulder straps; most scuba diving in SA is done from “Ribs” or Rubber Ducks (they have no ladder). At the end of the dive, the diver unclips the shoulder straps, hands the bcd to the skipper and hauls him/herself over the pontoon sides of the duck, inelegantly bellyflopping onto the deck. 

In Europe, Australia and many other countries,  the diver hands his fins to the deck hand and gracefully walks up the ladder with bcd (and tank) on his back.  In case you are wondering, the blue image on the left above is a rib or dive duck.  Note the height of the pontoon above the water. (We don’t actually dive from the little rubber duck at the top of this article)! Stab jackets are still enjoyed by many underwater photographers as the “all around air chamber” does what it’s name implies – “stabilises”.

Ok here we are, back to the modern bcd, so now we need to add a few more modifications to jazz up everything! Notice that there is no wrap around jacket near the “rib cage” and voila, we have a back inflation bcd! A bit more comforable for some divers as there is no air pushing against one’s ribs. Look at the little red “handles” in the front left and right lower sides of the jacket – these are pull handles for integrated weight pockets – another invention, that some divers find more comfortable than the traditional weight belt! (Psst – most divers dive overweighted – but that is for another article)!

Ok, what next?

Normal recreational scuba diving doesn’t provide enough adrenalin for some divers so along comes the technical diving “wing”. This type of buoyancy device kind of looks like a back inflation (which it is) the main difference is that it is usually an upside down “U” bladder, with a minimum of utility pockets and accessories. Techies prefer this type of device as it is more streamlined, often has a crotch strap (yep! for comfort and proper fit) and minimised mass and bulk.

The one that works for you!

Yep jump in the water with several different ones until you find the one that works for you! All your reputable dive shops have demo models that you can take for a test dive. The horse collar and stab jacket are not readily available so you are most likely going to experience the jacket type, the back inflation and the wing are your popular choices.  If you test drive more than 6 bc’s and can’t find one you like – you are probably not going about this correctly. 

A tiny bit of trivia  –  the ancient looking orange thing here is the only buoyancy device that qualifies as a life jacket – as it keeps the diver’s face out of the water!

 

 

–  Article provided by Russ Davies, Normalair Equipment Officer 

 

Do you have an interesting article you would like to share with us? Get in touch here.                          

 

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Spring Braai Run Down

On Saturday the 2nd of September we hosted our annual NUC Spring Braai, the weather was perfect and a good turn out meant we had an absolute blast of day. The snoek braai, prepared by Marcel and Spy went down a treat, so did all the ice cold beer!

We also hosted our very first NUC beer pong competition, which provided much entertainment all round and set the tone for the rest of the afternoon. Well done to Tom and ‘The Dragon’ for winning the beer pong competition and the floating trophy in a hotly contested final which went down to sudden death with Daleen and Mark, we hope you will be back next year to defend your title.

The typical booze cruise that followed on Bert’s Tub was short but hilarious and enjoyed by all aboard, for me this is always a highlight of any NUC function on the dam!.
 
Well done to Vince, Tom and Marcel for cleaning up the awesome spread in the raffle, from dive trips, model cars, dive and spearo knives and Jeep gear. A big thank you also to everyone who bought tickets for supporting the club and to the sponsors of the prizes (African Dive Adventures, ORCA and Arnold Chatz Cars).

These social events are not only what makes our club unique but also are also an important part of our fundraising to be able to keep the oldest dive club in Joburg alive. Thank you to everyone who came and enjoyed the day with us.
 
In case you missed out; don’t dispair! The NUC committee are already hard at work preparing for our next event, the annual Beerfest on the 28th of October – as per usual, everyone is welcome and all are encouraged to bring a guest or two.

We also have a trip planned to Ponto at the end of September, if you are keen you can find details about this trip below, on our website and Facebook page. If you have any questions please feel free to give us a shout.
 
Again a huge thank you to all who helped organise and who attended for making the day a success – here’s to many more.