Whats the advantage of Enriched Air?

Many divers I talk to or over hear in conversation often think that Nitrox is used for deep diving, this in fact is the biggest misconception scuba diving. In fact the deeper you dive the less oxygen is needed in the cylinders, to maintain a safe partial pressure of 1.4ATA on bottom.

The first evidence of a dive using enriched air in 1879 by Henry Fleuss, who was a master diver for Siebe, Gorman & Co. of London. He was breathing a mixture of 50 to 60 % oxygen enriched air in a large fresh water tank, a week later he logged a dive in open water with the same mix and equipment. Siebe continued his research into Nitrox mixes and between the two World Wars he introduced the technique of using different concentrations of oxygen mixed with nitrogen. This was used to great effect by British commandos during World War Two who used oxygen-enriched air rebreathers. Their rebreathers used a mix of 45 to 60% oxygen which had a greater maximum operating depth than their opponents who used pure oxygen rebreathers were limited to 6mt / 20ft.

If we breathe Nitrox during our dive we gain significant bottom time before we reach our no-stop time. The exact amount of extra bottom time will depend on the depth that we are diving to and the Nitrox mix that we are breathing.

So for an air dive to 30mt / 100ft the partial pressure of nitrogen during the dive is

4 x 0.79 = 3.16bar.  If we are breathing Nitrox with a 32% oxygen content (and 68% nitrogen) then the partial pressure of nitrogen is 4 x 0.68 = 2.72 bar.

So as the inspired partial pressure is lower when breathing EAN32, the tissues will on-gas slower at any point the same tissue will contain less nitrogen than if the diver had been breathing air. Oh one other thing, it makes you look COOL!!!

What will you learn in your Nitrox theory?

  History of Enriched Air Nitrox (EAN)
  Physiology
  Oxygen
  Nitrogen
  Physics
  Pressure review
  Partial pressures
  Equipment Considerations
  Forty percent oxygen content and less
  Above 40 percent oxygen content
  Dive Tables
  Equivalent air depth (EAD)  introduction of concept only for demonstration
  EAN tables
  Switching mixes on repetitive dives
  Dive Computers
  Mix adjustable
  Oxygen (O2) integrated
  Advantages and Disadvantages of EAN
  Use as air for physiological advantage with air tables or computers
  Use to extend no-decompression bottom times or shorten surface intervals
  Oxygen toxicity hazards and depth limits
  Discussion of myths and facts regarding EAN mixtures
  Procedures
  Use and theory of oxygen analyzer
  Gas analysis and logging
  Common Mixing Procedures
  Partial pressure blending
  Continuous blending
  Membrane separation system

Why use Nitrox on Roatan?

Why you ask?  Take advantage of staying 33min on the shipwreck "El Aguila" instead of 16min on air, air supply permitting of course.

"El Aguila" shipwreck in Roatan, Honduras

"El Aguila" shipwreck in Roatan, Honduras

Travel out to the other shipwreck further up the coast "Odyssey" and explore the triple decker super structure on Nitrox.  Again spend up to 35 min or so enjoying the large wreck without being pushed by no-deco limits of air.

"The Odyssey" shipwreck

Or take advantage of diving a divesite on the south west tip of the island known as "Texas" , once you swim into the large barrel sponge area it has a depth of 18 to 21mts 60 to 70ft, whilst diving Nitrox you will be able to enjoy your time on bottom and not be limited to your no-deco limits on air.

"Texas" divesite area....

The PADI Enriched Air Course will approximately take the student a day of classroom theory, dont worry though we have an air-conditioned classroom to kick back and relax in. 

How do you make an Ocotopus laugh? (with ten tickles)

I’ll start this by declaring I am deeply fascinated by octopuses. My first encounter happened while in Indonesia. I had 7 dives logged and was on my last dive in AOW. Octopuses are Houdini level experts at hiding and are rarely seen during the day as they are nocturnal feeders. Still, I held onto hope and it happened. Casually as could be, the instructor and I saw a small octopus rapidly changing colour, strolling across the sandy ocean floor. I was immediately fascinated and have held onto that novel experience since.

Of all the invertebrates that lack a backbone, octopuses are the most like humans. Partly how they maintain eye contact. Now, I don’t know about you but the minute I’m below - I’m looking for a fish connection. I am constantly creating scenarios in my head of swimming by Margaret, the porcupine fish who, no matter what the current brings in, is ALWAYS playing with a smile. Or I’ll swim by the ALWAYS grumpy goby, and start a dialogue... “Seriously Gerald, could that bottom lip stick out any further? I think you’ve perfected the Robert De Niro impression. She had a sex change 19 years ago….MOVE ON GERALD!”

It’s common to see multiple octopuses on the reef during a night dive here on Roatan.  (Photo courtesty of Alex Harper-Graham)

Reef fish only really make eye contact for 5 seconds while swimming away from you, constantly looking over their tail fins, waiting for the ultimate attack. A girl can only take so much rejection before she swims off to stress out another fish you know? But octopuses are different. In a staring contest, they’ll most likely win. It’s impossible not to sense the intelligence behind their eyes. Their many other attributes speak across the human experience. Their dexterity could make any acrobatic jealous, any chef would be envious of their hundreds of taste sensitive suckers and any magician should only dream of being as capable of escaping a seemingly foolproof container. This distinguishes them from other intelligent mammals like dolphins, which for all their smarts are limited by their anatomy and can’t (easily) unscrew anything.

Octopuses are ink-credible! (Captured by Alex Harper-Graham)

On the other hand, octopuses may be one of the most extra-terrestrial creatures in the ocean (have you seen their comparison in Arrival? They have 3 hearts and blue blood. As defense mechanism, they have evolved to eject ink while making a getaway. They have no bones. Their only inflexible body part is their beak and a nub of cartilage around their (amazing) brains. As a result they can move through any gap, hole or crack larger than these unyielding body parts.

It's easy to become a sucker, observing the common octopus (Captured Alex Harper-Graham)

Just as humans are mammals, Octopuses are cephalopods, which is Greek for “head-foot”. Literally, their anatomy is this weird. They have arms attached directly to one side of their head and their torso (a bag like sac) attached to the other side of their head. If you didn’t know, cephalopods is a category that captures snails, clams, slugs and oysters amongst others and they were the first predatory animal to hunt in the ancient seas. This category evolved over 500 million years ago from a small animal with a shell like a witch’s hat.

If that isn’t enough, if at this point you still need convincing that octopuses are worthy of your further attention, the nervous system of the octopus sets it apart from any other creature (as a result it is a constant topic of debate amongst concerned professionals whether the octopus is a conscious creature)

Octopuses have 500 million neurons. Honeybees and cockroaches, which after cephalopods, have a claim to the Earth’s most neuronally rich invertebrates, only have one million. (Humans have 86 000 million neurons)

Evaluating the intelligence of other animals more often than not tell us more about our own intelligence, and I am constantly playing with this idea during every dive, while trying to find my next fish connection. Experiences and interests, such as the one with the common octopus, creates further motivation to preserve the lives of other organisms so they can continue to adapt and grow, just as humans do, in an ever changing environment.

Rescue Rain Day

Very rarely do us Dive Masters get a snow day, but that is exactly what happened one morning last week. Let me start with; diving during a rainstorm is a treat. You are going to get wet no matter what, so why let precipitation deter you from a good time? To be completely unaffected by any elements, submerged, 10, 20, 40 feet under water, floating on your back, looking up as drops disrupt the surface in a static, white noise sort of manner, is a calming, novel experience. There are dangers associated with diving during a storm, though very few actually influence behaviour underwater. Instead it is the entry and exit from the boat during a storm where most accidents happen.

On this day, last week, the water and wind were consequently too rough to even consider a boat dive from any side of the island, so the morning boat was cancelled, leaving 8 dive masters and 4 instructors puttering around the shop. A movie on skills (sans popcorn) was turned on for review and all dive masters settled in. Not 35 minutes later, the instructors interrupt the movie and being yelling about a missing diver. We all quickly recognize the interruption as a drill and even quicker scatter like cockroaches being chased by a flame. The next 40 minutes evolved into what can only be described as mildly controlled chaos. The missing diver was eventually located but was unable to be resuscitated as her bottom time was well over 20 minutes. The supervising instructors were disappointed, but as we were all reminded by our newest DM from Switzerland, drills like the one we just bombed, are the reason we all become better, as individuals and as a team. Rather than thash out every error we made, I’m going to isolate and highlight the correct response to an emergency which is an important refresher for all divers of any level.

Missing Diver/Search + Rescue

1.       Assess the Situation

a.       Before anyone moves in any direction, assign a lead. No matter what the conditions, you will be working as a team, but it is far less confusing and much more efficient to know who is delegating tasks and who should be aware of all information passing through.

b.      Collect all information. Who is missing, Where were they last seen, When were they last seen, What are they wearing, How much air did they have left, Why did they go missing?

2.       Create a Plan

Denver using proactive teaching techniques

a.       The DM’s were informed of the missing diver in a classroom where we were watching a movie. We had a white board, multiple maps, a spine board, emergency oxygen, first aid, and various other useful tools, which you can be sure none of us took advantage of, because in the excitement we all just bolted for our equipment. What we should have done was draw the search area/dive site on the white board, and assign teams and search patterns.

b.      Assign roles to your team.  There were 8 of us. Perfect for one snorkel team of two, two scuba teams of two and one team of two to stay on land. Discuss search patterns, recall signals if a team finds the diver, assign gear, compasses and have the land team put emergency services on standby while checking the missing diver’s hotel on the off chance they have surfaced and gone home.

3.       Implement

Sean successfully applying CPR

a.       After this crucial first and second step, MOVE! Time is crucial for increased survival rates. Get your gear and get to the water. Have one more meeting before entering the water to ensure everyone is clear on the plan, or to accommodate any changes.

b.      Communicate! When you create a plan stick to it. The easiest mistake to make is to become an independent member and abandon your team with dreams of becoming a hero.

Anthony tells Sean a secret once recovered

c.       Depending on the diver’s condition when found, the recovery standards will differ. The most experienced EFR trainee should work on the patient until EMS arrives.

At the end of the day, we all learned that you cannot succeed without the cooperation and help of your team. We became stronger as a group and will definitely be carrying this lesson into many other experiences.

Rescue Rain Day narrated by Chloe

Caribbean reef fish of Roatan

Here are some photographs of just some of the variety of fish we have here in Roatan, Honduras. The location of these shots are mostly taken in dive sites ranging from Pablo's to Spooky Channel. How many can you identify? If you haven't done so already, ask to do a fish identification dive and one of the instructors will go through with you, the best techniques for finding and learning as many fish as possible.

All photographs are taking by the talented Alex Harper-Graham find more photos by clicking the link www.alexandrahbphotography.com

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Some of these fish can be spotted swimming amongst the beautiful mesoamerican reef, and the others are more shy and hide in the coral and take cover from predators.

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As the staff are busy looking for exotic features and creatures for you, safety is still our first concern with our customers making sure we do air checks when needed and not to worry if you run low on air, we always have a divemaster intern that will assist your safety stop and buddy with you back to the ladder.

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Be sure to follow us next week on an adventure, we haven't been able to promote funday friday lately because of weather issues.  Next week will be worth waiting for, make sure to follow along.......  happy bubbles from CTD

Scuba diving amongst Hawksbill turtles in Roatan.

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All photos courtesy of www.alexandrahbphotography.com

The hawksbill sea turtle (Eretmochelys imbricata) is a critically endangered sea turtle belonging to the family Cheloniidae. It is the only extant species in the genus Eretmochelys. The species has a worldwide distribution, with Atlantic and Indo-Pacific subspecies.

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The hawksbill's appearance is similar to that of other marine turtles. In general, it has a flattened body shape, a protective carapace, and flipper-like limbs, adapted for swimming in the open ocean. E. imbricata is easily distinguished from other sea turtles by its sharp, curving beak with prominent tomium, and the saw-like appearance of its shell margins. Hawksbill shells slightly change colors, depending on water temperature.

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All text is found https://en.wikipedia.org/wiki/Hawksbill_sea_turtle

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While this turtle lives part of its life in the open ocean, it spends more time in shallow lagoons and coral reefs. The World Conservation Union, primarily as a result of Human fishing practices, classifies E. imbricata as critically endangered.[1] Hawksbill shells were the primary source of tortoiseshell material used for decorative purposes. The Convention on International Trade in Endangered Species outlaws the capture and trade of hawksbill sea turtles and products derived from them.

Macro photography diving - top tip to find the small stuff

Today, was a clear, sunny and typically warm day in Roatan. The diving was also clear, warm water and little current, a perfect day of searching for the little critters underwater. Go slow and you'll always find more.

Macro tip of the week, look for Sailfin Blennies in sandy areas. Their little black or white heads will generally be seen in an isolated coral head on the sand. If you're lucky and patient you might even see them fully come out of the hole and display their amazing dorsal fin.

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Sailfin Blenny, Deep Turtle Crossing Dive Site

Photo courtesy of Alexandra Harper-Graham www.alexandrahbphotography.com

Superbowl Sunday + BBQ at the diveshop

Your big winners of the night!!!  Alex and Monty won three times on the squares, about 160USD... whoohoooo

Super Bowl LI will be the 51st Super Bowl and the 47th modern-era National Football League (NFL) championship game. The American Football Conference (AFC) champion New England Patriots will play the National Football Conference (NFC) champion Atlanta Falcons to decide the league champion for the 2016 season. 

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As it stands all bets are in for the game, good luck everyone!!

Burgers and Dogs

BBQ Chicken Wings

Saskatchewan Roughriders would love to take on the Patriots or Falcons!!!!  Greatest football team in the world!!

Tonight on the menu will be burgers, weiners, kabobs, chicken wings and much more... Its a potluck dinner so bring what you want to throw on the BBQ, or bring a side dish.

Watching it on the HD Projector, so a 10ft screen for tonight.

End of the week Sunset Cruise with family and friends.

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Photos courtesy of www.alexandrahbphotography.com

And so ends another week of diving at the shop.  The weather started with a short two day storm which we fled to Flowers Bay for some south side diving. By Wednesday we were back diving in west end enjoying dive sites like Texas, Hole in the Wall, Peters Place, and Bears Den.  To end every week we have Funday Friday, a customer appreciation day with sunset drinks, fishing, music, dancing, and shenanigans with all the dive staff. 

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Looks like were off to the south side on sunday..... booooooooo.... However we are keeping the big boat over in Las Palmas for the week, which means we are diving Marys Place, 40 ft point, Mr bud wreck, Prince Albert wreck, Valley of the Kings, and many more... 

Potlicker will then stay in Flowers Bay for the open water courses and DSD,s for the week.  Be sure to come down and check out at the wave action at our friend Daryls resort, Lands End..  Amazing views and cheap beer!!

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Outta here, see ya!!

License to kill!!!!!

Chantal and Rachel slaying lunch

Ever since we arrived on the island, Chantal and I knew we wanted our Lionfish licenses. Although they are pretty, in the Caribbean, Lionfish are an invasive species. There are a number of theories on how they arrived from the Indopacific, but no matter who or what is to blame, Lionfish are a problem in Roatan. They have no natural predators, voracious appetites, and a strong resilience to environmental factors allowing them to easily spread through the Caribbean and beyond. Our licenses were obtained through the Roatan Marine Park, the NGO responsible for protecting over 941 hectares of coastline and sea surrounding our island. Although the license was 50 dollars (a little pricey for a DMT) We knew our money was largely a donation to the Marine Park, and when you have a passion for diving, supporting local conservation efforts is a no brainer.

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Plus, they gave us spears!

After we watched the video https://youtu.be/yRjs78-5F-Yand had a short talk with Nic, the Marine Infrastructure Coordinator, we headed out to the sand patch to prove our worth! The harvest of lionfish is important for the health of the reef, however the irresponsible use of spears could potentially be worse. Bad buoyancy and missed shots risk hits to the coral, damaging thousands of years of growth.  So before we were able to head out and hunt we had to prove to Nic that we were capable. He provided us with a number of coconuts so we could get a feel for the action of our spears. After we were comfortable he set up a ‘pretend’ reef and placed the coconuts in small alcoves (where lionfish typically hang out), and we KILLED those coconuts!

 I think even Nic was surprised.

With our licenses to kill, Chantal and I can’t wait to join the fight for the control of lionfish in Roatan. The free ceviche doesn’t hurt either!