Diver Training? 5 tips to get the most out of it

Well, we have had a bit of a break from blogging over the past couple weeks, as things have been hectic over here in Cyprus with dive training courses and safari diving,  Now, however, the winter season is upon us and things are starting to settle down a bit.

Conducting all these dive courses over the past weeks has brought, once again, to the forefront of our minds the problems that divers often have with training courses, regardless of level. From a Try Dive, PADI Open Water to TDI Advanced Nitrox and even Trimix courses, how can you get the most out of your Dive Training?

1. BE INTERESTED!

To get the most out of any kind of training, you simply have to be interested in the subject matter.

Before beginning any Open Water Course, we advise the student to take part in a try dive session to make sure they enjoy Scuba Diving before investing in the manuals and possibly equipment. There is nothing worse than spending a whole lot of money to realise that this isn't the sport for you, even if those people are few and far between.

Equally, although it is nice to have a common sport in families and partnerships, if your husband, daughter, friend etc. really isn't interested in Scuba Diving, they won't get out of the courses what you want them to. 

Everyone should try it! Most people love it! But don't force it.

Technical Diving and Sidemount Diving are another aspect of the same thing. We have seen a number of divers coming to Cyprus who just want to scuba dive but because Tech diving and Sidemounting have taken off in such a big way, they are worried about being left behind.

This Diving is NOT for every Diver and if it isn't something that really interests you, then leave it alone. There are plenty of dive sites for recreational diving, and plenty of training courses you can take to maintain your interest and keep learning, so stick with what you enjoy.

2. PAY ATTENTION TO YOUR INSTRUCTOR

When we teach Scuba Diving, an instructor will usually brief the dives and the skills on land before getting in the water. Once in the water, we will demonstrate the skills for you so you see how they should be done before you try them yourself.

Listen to the briefings and try to visualise yourself doing what the instructor says. Even mimic the action on land before getting in the water to start building that muscle memory from the beginning. The instructor will also be able to give you tips drawing on his experience of where other students go wrong and paying attention to this will hopefully, prevent you from doing the same thing.

3. RELAX

Dive Students, of all levels, often try and race through new skills in an attempt to get them over and done with.

The problem is that when you rush through a new skill, you do not give yourself enough time to consider what the next action should be and it tends to go a  bit wrong.

When you relax and take your time over completing a new skill, you give your brain time to process what comes next and you are more likely to get it right. And, if the skill is an emergency drill that needs to be completed as fast as possible, such as shut-downs on a twinset, don't worry. As you practice the drill and it becomes muscle memory for you, the speed will come but get the steps correct to begin with.

4. DON'T BEAT YOURSELF UP

If you are learning something new and just don't feel like you are "getting it", it can be very frustrating and it is very easy to start to feel like you cannot do it!

The reason we take a course is to learn. If we could already do it, why would we need to pay someone to train us and of course, learning something new will inevitably mean doing something until you can do it right.

People also learn at different paces and in different ways, so a good diving instructor will be able to help you grasp those diving concepts regardless of the kind of learner you are and how long it takes you.

5. ASK QUESTIONS

Again, this comes down to learning something new and the old adage that "there are no stupid questions".

You are paying your instructor to teach you something and so if there is something that you don't understand or you do not know, ask them and they will happily answer any questions you have.

We extend that for our student divers and everyone who leaves Scuba Tech knows that if they ever need information about equipment, training or scuba diving in general, we are always at the end of an email or the telephone.

4 things everyone should consider before diving a dry suit

It is that time of the year again! The water temperature has dropped to the low 20s and the drysuit comes back out of storage.

Drysuits are excellent pieces of equipment for scuba divers but you have to buy the right suit for you and have the correct training to use it safely.

So, when you dive with a drysuit, you need to consider a couple things

1. What Material is it made from?

Drysuits are usually either neoprene (sometimes crushed neoprene) or tri-laminate. Both have different properties and affect the way you dive.

2. Undersuits/ Thermals

Neoprene drysuits generally have more warmth than tri-laminate and so the diver doesn't need to wear the same amount of thermals as you would in tri-laminate. Be aware though that if the neoprene is not crushed, the buoyancy changes when changing depth can be quite severe.

Obviously the amount of thermals you wear and their thickness is also going to affect buoyancy, so be sure to complete a proper weight check when altering them



3. Fit & Flexibility

Generally speaking you do not want a drysuit that is restrictive at all but if you are a technical diver, you will want to consider your flexibility in a drysuit. This is particularly the case when diving open circuit, twin tanks. If you have not got the manouverability to reach your tank valves, you will be unable to complete the basic drills and skill sets.

On the other end of the scale, if you have a dry suit that is too big for you, it will be too easy for air to migrate around it while you dive.  This causes you to be less stable in the water and leads to an uncomfortable dive.

4. Buoyancy Control

I see many divers who come to dive in Cyprus in the winter in their drysuits trying to use the drysuit as their only means of buoyancy.  While I realise this is often the way divers are taught to dive in their drysuits, it is wrong.

You have a buoyancy control device (BCD) so use it!


As I said before, the more air in the suit, the more it migrates around and the less stable you are in the water. You will also find that you will get gas bubbling out of the neck seal when there is too much in there.

Divers should only use the drysuit to take off the squeeze and other buoyancy should come from the BCD or wing. This will make you a more controlled diver and give you a more comfortable experience.

While many divers say diving in a drysuit takes a lot of effort and is uncomfortable, I have to admit, it is my preferred way of diving especially at this time of year. With the correct training and weighting, I am sure you will love drysuit diving too.

I shot the Moray... but I did not shoot the Octopus

That's not really true to be honest.

When I am underwater, I tend to shoot everything and anything whether it moves or not!!

What can I say.... I just love underwater photography. Every opportunity I get (when I am not teaching or guiding) I like to take the camera and see what I can get.

My photos are not award winning but I do get many compliments for them and so, I would like to share my top 5 tips with you for taking underwater shots.

SORT OUT YOUR BUOYANCY

You will never... and I mean... ever... get a decent underwater photograph of anything if you cannot control your own buoyancy underwater.

We have enough problems with motion blur from that fast moving fish that will not pose for love nor money but add to the mix a photographer who is flailing around because their buoyancy control is none existent and all you will get is a blurred, out of focus nothing-ness.

Once you have control of your buoyancy and position underwater, you will find the results of your efforts much more appealing. Plus, you won't have lots of backscatter in your photographs from all the sand and silt you have kicked up and the photographers behind will be much more grateful because they can get a photo or two aswell.

This leads to my Second Tip

HOLD THE CAMERA WITH TWO HANDS

Again, this is about control and stability. You are more likely to get a sharp underwater photograph if you hold the camera with two hands, so when you depress the shutter button, the camera will not jerk underneath.

Obviously, this is much easier to do when you can control your buoyancy and have mastered finning techniques such as the back kick. In this way, you won't have to hold on to that rock or push yourself backwards, away from the subject with your finger on a ledge. Both hands will be free to keep the camera steady.


LEARN HOW TO USE THE MANUAL CONTROLS

You have invested in a nice camera system with strobes and housing and somewhere in the bundle of knobs and dials, there is a manual setting which gives you control over the camera.

Find it and Use it.

Manual white balance is a setting that is on most camera systems these days and if you are not already using it, well you should be (unless you are using a strobe then keep it in auto).

Middle range camera systems also offer a bit more control to the user. You will be suprised at the difference you can get in your underwater photographs if you can just learn to set the proper shutter speed, aperture and ISO.

You don't even need to be in the water to practice. Set about the house with camera in hand and get your family and friends to be the fish...ahem... I meant models!! You will soon pick it up and there is loads of information available on the web.

As a rough guide, here in Cyprus on dives down to around 20metres, I find that an ISO of 125, shutter speed no slower than 1/125th of a second and a middle of the road aperture of around 4.5 seems to work quite well. Sometimes I will adjust the aperture, depending on the effect I am looking for but generally I will adjust the amount of ambient light by changing the shutter speed.



STAY SHALLOW

The best life and colours are in the shallows, so if you are planning your dives for underwater photography stay within the first 15metres or so.

Of course, this isn't always possible. Sometimes the subject is found deeper or you are wanting to get images of a wreck down at 30-40metres and, if this is the case, my final tip is...



INVEST IN AN EXTERNAL STROBE AND WIDE ANGLE LENS

When you go deeper underwater, you lose ambient light and colours. Red is the first to go, then orange and yellow until finally, you are left with just blue.

The best way to put back lost colour at depth is to use a flash.

All cameras come with an internal flash, which can be used in underwater photography but, as soon as there are any particulates suspended in the water, you will find that you get a lot of backscatter. The further you can position the flash from the lens, the less noticable this effect is, which is why I recommend an external strobe.

Not only does it help reduce backscatter but you would usually mount the external strobe on a flexible arm, which means you can adjust the position of  the light to get numerous lighting effects on the subject.

Again, the external strobe offers more control for the underwater photographer.

With the Wide Angle lens, we can get closer to the subject, reducing the amount of blue water between us and giving better quality pictures and making the strobe more efficient.

So, from an amateur but extremely enthuaiastic Diving Photographer, these are my tips for better underwater photographs.

They are simple, common sense but I so often see people not applying them and wondering why the photos they take are not very good. Hopefully this will help you take better pictures.

Happy shooting everyone

Dive with the Devil... on the Devil's Gas!!

This is the image I use to stamp people's log book when they come diving with me. I think it is quite apt, since I always dive on, what was once considered to be, the Devil's Gas

 

NITROX

 

 

 

Nitrox was actually one of the first specailties I took after certifying as a Scuba Diver. At the time, I had no idea how useful and well-used this certification would be but with time, it has become apparent.

 

What is Nitrox?

Nitrox is quite simply air, with a bit more Oxygen added!!

Back to school science, you may remember that the normal air that we breathe is made up of around 78% Nitrogen and 21% Oxygen with a few other gases that barely make up 1% and so are negligible. For the sake of ease, we say 79% Nitrogen and 21% Oxygen.

 

 



Nitrox contains more Oxygen, so something must be removed from the mix to accommodate for it. So, we have more Oxygen and less Nitrogen! As you can see in the diagram above, 32% Nitrox contains 32% Oxygen and 68% Nitrogen.

What's the benefit?

Think back to your initial Scuba Diving Training and Decompression Planning. The gas in your breathing mix, which limits your time underwater is Nitrogen.

While we breathe underwater, we have a certain amount of time we can stay at depth before our bodies have absorbed enough nitrogen that a direct ascent to the surface would not be possible. If we overstay this time limit, we have to complete decompression stops (as opposed to the Safety Stop that we all make in recreational diving) to prevent the nitrogen coming out of our bodies too fast and forming bubbles (decompression sickness).

By reducing the amount of Nitrogen in the gas we breathe, we can extend the amount of time we can spend at depth. With 32% nitrox, you can spend almost twice as long at 30m than you can when you breathe air!

Some Divers believe that nitrox makes them feel less tired after multiple dives than they would if they were breathing compressed air, although I don't think there is any substantial evidence to prove nitrox has any great influence on this. It is more of a personal thing

The biggest health benefit for Divers Diving Nitrox comes into effect when you dive Nitrox on air tables.

This means you take the conservatism of diving on air (shorter no decompression limits) but have the added "buffer" of increased Oxygen in the mix. This means the diver stays that bit further away from Decompression Limits and should be better for the Diver!!

Although, be aware, if you are using Dive computers set to air while you are in fact breathing Nitrox, you must know your Maximum Operating Depth so you do not accidentally exceed it because your computer says you can!


What's a Maximum Operating Depth?

Oxygen is not a deep Diving gas. In fact, the deeper we go, the less Oxygen we can use. Deep Divers, heading down to 100m will use a hypoxic breathing gas with around 12% Oxygen, which is too little oxygen to be breathed at the surface.

This is because, Oxygen becomes toxic when breathed at certain pressures. So we must know the Maximum Depth (MOD) we can safely dive our breathing mix to.

Nitrox is perfect though for the recreational limits between 15 and 40m and Divers must work out their MOD for the mix they are breathing. For example, 28% nitrox can be safely breathed down to 40m, whereas 32% nitrox can be safely breathed to a depth of just 33metres.

This all comes with the training.

For multiple diving around the 30m range, I don't think you can beat diving with Nitrox, simply for the benefit of the added time you get to spend underwater enjoying the sites and wrecks and it is definitely becoming more mainstream today.

All the major agencies now offer Nitrox training courses and it is, not suprisingly, one of PADI's best selling specialties.

So, if Nitrox is the Devil's gas, I am certainly the Devil...Gas me up!!!

 



Oooooh, you little NUDI!!!

Diving in Cyprus, we are fighting the long fight against the over fishing which is endemic in this region.

We can dive on a Saturday and see lots of various fish life in abundance all around the coast line and come back on a Monday to find all life has been decimated. It is a terrible shame, as the fishlife does not take long to replenish and if it could just be left to give the fish a chance to grow to maturity, we could start taking on the more established Diving destinations.

However, in the midst of all this, there is one sea creature, which never fails to be seen on a Dive in Cyprus. More abundant in the winter months when the waters are cooler but ever present in the deeper waters under the thermocline in the Summer, I am, of course, talking about the beautiful Nudibranchs.

Nudi's (as we like to call them) are a group of soft bodied, gastropod mollusks. Unlike others of this kind such as; whelks, conches and periwinkles, the nudi sheds it's shell after the larval stage.

The word nudibranch comes from a mixture of Greek and Latin meaning "Naked Gills" and they can be distinguished by their striking forms and exquisite colours.

Found everywhere around the world and in every ocean and sea, the number of species of nudi that have been described is around 3,000 and new ones are being identified almost daily!! They are most commonly divided into 2 types.




1. Dorid Nudi

Dorid's have the Branchial Plume that forms a cluster on the posterior of the nudi's body.





2. Aeolid Nudi

Aeolid's have Cerata instead of the Branchial Plume. Cerata are dorsal and lateral outgrowths on the upper surfaces of the body.







Here in Cyprus, the most commonly seen Nudibranchs are Aeolids. "Flabellina Affinis" (purple nudi) and the "Coryphella Pedata" (white tipped nudi) both have Purple bodies but while the purple nudi is entirely purple, the white tipped has (yes, you guessed it) white tips on their cerata!

These nudi's have simple eyes that can only really discern changes in light and dark. Instead , they
have sensitive antennae like protrusions called Rhinopores on top of their heads for detecting taste, smell and prey.

They may be small but all nudibranchs are Caniverous animals. They feed off sponges, hydroids, other sea slugs and their eggs and some nudi's are Cannibals, preying on their own species!! Not so cute now are they?

It is believed that the nudibranch's derive their colour from the food that they eat. Some camouflage into their surroundings while others have bright colours that stand out with vibrance which acts as a deterrent to predators. As a general rule, we are all taught, "the brighter and more colourful it is, the more dangeous it usually will be".Some nudibancs can even retain the poison from their prey to secrete as a defence mechanism against predators.

However, even with all these defences, the lifespan of the average nudi in the wild is only up to a year!

 

We used to see many different varieties of nudi here in Cyprus including the Tri colour Doris or the elegant slug but these are becoming fewer and harder to find around the Island, so let's appreciate the ones we have while they are here!!

I for one, am a big fan of the little nudi.

Scuba Diving- A Beginner's Guide

Thinking back over my years as a diving instructor in Cyprus, I began to think about the number of Divers that have come through the doors and the mis-understandings and cons I have seen over the years.

The problem is, that unless you know better, you do not generally know what to expect with a Beginner's Diving course, such as PADI Open Water, BSAC Ocean Diver etc but there are a few things that you should get  with any of these courses.

Access to Diver Materials

Usually in each Diving course that you take, the chosen Agency produces a manual containing all the
relevant Diver theory you will need to pass the course and build a solid knowledge base for future training and Diving.

PADI insist that each diver have their own manuals for each course, enabling the diver to have a reference to any of the information from said course in the future, which is a very good idea because, as a beginner, trying to cram all that information into 4 days means only a fraction of it will be retained and a lot of it will probably be forgotten quite quickly.

With the advent of online learning, manuals can now be replaced with an online code, which allows you to do the knowledge portion of the courses on-line. Fantastic for some but, I still like to have the solid manual in my hands and it is always best to check whether it will be cost efective for you. I have found the online training usually works out to be more expensive and you don't have the benefit of your instructor there with you to answer questions you might have along the way.

By the time you get to see your instructors, you will have forgotten what those questions were!!

Skills Sessions and Open Water Dives

Each agency breaks down the Diving Courses into Open Water Dives and Confined Pool Sessions. An easy way to check what you should be doing on the Courses is to check out the Agency's own website and it will describe the components of the courses.

So, for example, the PADI Open Water Course has 5 Knowledge Development Sessions, 5 Confined Water Skills Sessions and a minimum of 4 Open Water Dives.

BSAC Ocean Diver has some theory and knowledge development, 5 Confined Water Skills Sessions and 5 Open Water Dives.

No portion of the course should be signed off until the diver is comfortable and competent at that level. Remember that these courses are supposed to take a minimum of 4 days and trying to squeeze it into 2 or 3 is not going to produce high quality divers that can look after themselves in the water.

At Scuba Tech Diving Centre, we try to give our student divers even more time for diving by incorporating an extra Open Water Dive after each skill session. This is beneficial to the Diver, as you can only improve at Scuba when you spend more time in the water. However, I stress this is an additional dive and does not count as one of the 4 mandatory Open Water Course Dives. Do not allow the Dive Centre to combine your Skills Sessions with these compulsory Dives, as it is breaking standards and, as a trainee, you will not benefit from less time in the water!

A Proper Certification Card



 I think back to around seven years ago and a Diver walked into the Dive Centre here in Cyprus as an Open Water Diver wishing to Dive Zenobia.

We explained that you must be a minimum of Advanced Open Water for us to take you on Zenobia and he expressed an interest in taking the Advanced Course.

On production of his certification cards, it appeared he didn't have any. Having done his training in Mexico, all he was given was a sheet of A4 paper stating "This Diver is certified to Open Water Training Level with the Diving Agencies; PADI, SSI, Naui, BSAC and CMAS" with an illegible instructor number at the bottom.

The gentleman in question was obviously devastated as he had paid a lot of money for something that wsn't real. He had even gone out and bought all his own equipment.

Unfortunately, there wasn't a lot we could do to help other than re-train and get him a proper certification card.

In resort, you should receive a Temporary Personal Identification Card (PIC) on completion of your training either in paper format from the dive centre or via email direct from the agency. These temporary cards last approximately 90 days, which should be plenty of time for your actual plastic card to come through the post to you.

If you do not receive the actual card, contact your instructor, who will be able to contact the Dive Agency direct to sort everything out.

Your certification card will usually have your picture on it too.

Supervision Ratios

Most Diving Agencies set ratios for the number of Student Divers that one instructor can teach at any given time. The maximum is usually 4 students per instructor but more students can join the group if the instructor has a Certified Diving Assistant.

Think about the quality of the training you will receive if you Learn to Scuba Dive in a big group like this. Sometimes, maybe it is better to pay a little more and get one to one training or just be in a small group of 2 divers to one instructor. Surely, this is better value for money!

So, there you have my guidelines for a Beginner's Diving Course. Regardless of which agency you decide to learn Scuba with, bear these tips in mind and know what you should be getting for your money and your Diver Training can be the best investment you will make.

Narcotics of the Deep... a Rapturous Dive

We all learn about Nitrogen Narcosis from our very first Diving Courses, be that with PADI, BSAC SSI, Naui, CMAS or GUE. It is an important consideration for any dives that we make but how well is it really understood in the Diving world?

What is Nitrogen Narcosis?

A Greek word (ναρκωσις) narcosis is derived from "narke", which means " temporary decline in, or loss of senses and movement".

Essentially, it is an alteration of consciousness as a result of the gases in our breathing mixes acting under pressure and a mixture of Dalton's and Henry's laws.

For those of you that don't remember them, this is the science bit... concentrate!!! (sorry L'oreal)


Dalton's Law

Dalton's Law states that the total pressure exerted by the mixture of non-reactive gases is equal to the sum of the partial pressures of individual gases.

We use it mostly in diving to work out our Partial Pressure of Oxygen at a given depth or our END (equivalent Narcotic Depth) for trimix

Henry's Law

 Henry's Law States that at a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.

This goes back to decompression theory and the fact that, in the most basic terms, as we go deeper and the ambient pressure increases, more of the inert gas that we breathe dissolves in the body to balance the pressures of gases in the body with the surrounding pressures outside.

How does that work then?

Very interesting, you say! I remember those laws now but what does that have to do with Nitrogen Narcosis?

Well, let's look at what we believe to be the history and mechanics of Narcosis first.

Narcosis was first described back in 1834 by Victor T Junod, who was a French Researcher. His description referred to symptoms of intoxication being present and he surmised this was due to the increased ambient pressure increasing the blood flow in the body, which stimulated the nerve centres.

There were a few more theories over the years and much of our knowledge of Narcosis today is based on the study of anesthetics. The best theory we have for Nitrogen Narcosis at the moment is the Meyer-Overton Rule.

Around 1900, Meyer and Overton (independently) observed the potency of general anesthetic gases by testing their solubility in a simple organic solvent. They used Olive Oil as the organic Solvent, which represents the lipid bilayer found in our bodies, which make up the cell membranes of almost all living organisms and viruses.

Inert gas dissolves into the nerve cells lipid bilayer (Henry's Law) and causes narcosis by altering the nerve transmission in many diffuse areas of the brain resulting in symptoms described as; Euphoria, Over Confidence, Anxiety, Loss of Judgement and/or Paranoia.

We Diving instructors often teach our students about Narcosis by describing the "Martini Effect". This is a comparison between the way we act as we go deeper underwater and the way we act when we consume alcohol. Essentially, for every 10m we descend, it is likened to drinking one martini.



Even Jacques Yves Cousteau famously called it the Raptures of the Deep!!



Nitrogen Narcosis is a depth related problem. As we go deeper, the ambient pressure increases and so does the partial pressure of our inert gas (Dalton's Law). Beyond 30m, where the partial pressure of Nitrogen (PPN2) is above 3.16ata, we usually can begin to feel these symptoms

Is it just Nitrogen that causes Narcosis?

As Divers, we don't just have to worry about Nitrogen causing Narcosis at depth. It is widely accepted that all breathing gases have a narcotic effect but to varying degrees. Below is a list comparing the solubility of some gases in the Organic Solvent. Remember the Bigger the number next to the gas the more soluble it is and the more potency it has for Narcosis

GAS	SOLUBILITY
Helium	0.045
Neon	0.300
Hydrogen	0.600
Nitrogen	1.000
Oxygen	1.700
Argon	2.300
Krypton	7.100
Carbon Dioxide	20.00
Xenon	25.60

As you can see, our two primary gases in the breathing mix; Nitrogen and Oxygen are similar in Narcotic Potency with Oxygen being slightly more Narcotic than Nitrogen.

So why don't we worry so much about Oxygen Narcosis?

It is believed that the Narcotic effect of Oxygen is actually lessened becasue our bodies metabolise it but, to be safe, we are taught to assume Nitrogen and Oxygen have the same Narcotic Potency.

The suprising Gas I think is Carbon Dioxide. With such high solubility in lipids, we can see why it is such a dangerous gas and how Hypercapnea can kill a Diver.

Carbon Dioxide causes increased blood flow to the brain and is therefore, believed to increase and augment the narcotic effect of the other Gases too. This is why it is dangerous to complete hard, strenuous activity while diving and Skip Breathing or Shallow Breathing is BAD!!!!

As you can see from the table, the least Narcotic breathing gas is Helium, which is why deeper divers tend to opt for a trimix containing lower percentages of Nitrogen and Oxygen and filling the gap with Helium.

Some agencies even advocate trimix within recreational limits. For example GUE (Global Underwater Explorers) suggest that below 30m, breathing mixes should contain helium for less narcosis and better Work of Breathing.

Prevention and Management

The full complexity of Narcosis is not yet fully understood. However, the mechanism and primary agents responsible seem sufficient at the moment for us to make good decisions with regards to the gases we should use at certain depths while diving.

Recognising symptoms can be difficult due to the impairment they cause. The most dangerous aspect of Narcosis is the loss of good judgement and decision making abilities. If not recognised, these can lead to drowning. Good job we have our buddy there to help us out then!!!

To prevent Narcosis, avoid deep diving, strenuous activity, being cold, stress and Carbon Dioxide retention. If you are diving deep, use the correct gas mixes for the depth and keep your Equivalent Narcotic Depth above 30m.

Should you feel the symptoms of Narcosis, simply ascend and you should feel the symptoms diminish, although I have read reports recently that they may not vanish altogether until hours after you have surfaced.



We just don't know!!

Narcosis seems to be another Diving Problem that we are still only just learning about. It is dependent on the individual Diver's susceptibility to Narcosis and their health on the day of the Dive and many other variables that we just do not know enough about.

Be prudent, be conservative with your dives...

and if Nemo looks like he needs your reg more than you do, you are probably narked!!!

Rebreather Diving... Is it the future of Scuba?

It seems like a strange question since I am a Megalodon Rebreather Instructor. Am I questioning whether Diving a Rebreather is the way forward? Certainly not! But, is Rebreather Diving the future of Scuba?

Since I have a TDI Megalodon Rebreather Mod 1 course running this week, this is at the forefront of my thoughts.


What Is a Rebreather?

In the most basic terms, a Rebreather is a breathing apparatus that recycles the air that you exhale, removing the Carbon Dioxide (CO2) and re-injecting Oxygen (O2) to replenish that which you metabolise with each breath.

Rebreathers are not limited to the Underwater World. You can also find them being used by Firefighters, Miners, up mountains, in hospitals and even outer space! In fact, you can find rebreathers being used in many places where the breathing supply is limited or the environment is toxic.

But we are talking about rebreathers that are used for Diving purposes.

How does a rebreather work?

When we breathe underwater on regular open circuit scuba, we actually waste a lot of gas. With every breath we only metabolise around 4-5% of the inhaled Oxygen and the rest is exhaled into the water column and is wasted.

Rebreathers are a means of making this gas management more efficient and since I am a Megalodon Instructor, I will focus on this unit.

The Megalodon is comprised of 2 cylinders of gas; one Oxygen to replenish the Oxygen that our bodies metabolise as we breath and the second can be either a trimix or air, which is used for inflation and to "dilute" the oxygen in the mix. Therefore, we call it Diluent.

These Cylinders are attached by mounts to an aluminium canister with a scrubber inside. So called because the Scrubber unit contains a lime product which reacts chemically with our exhaled Carbon Dioxide to "scrub" it from the breathing mix. We use sofnolime 797 in the Meg and there are 2 types of scrubber you can have; Radial or Axial but this is another topic all of its own.


At the top of the scrubber can is the "Head", which contains the Oxygen Sensors (3 of them) and the battery packs and is attached to the Primary and Secondary hand sets, which give you the information you need to dive the rebreather. On the Meg, both handsets are completely independent so that, were one to fail, you could surface safely on the other.

Fixed to the can and the cylinders is the loop and the counterlungs, which are the parts we breath from.

The counterlungs are collapsible bags and are needed because without them, it would be like trying to breathe from a plastic bottle and the work of breathing would go through the roof! The loop itself has the mouthpiece and a shut off valve to prevent water entering the loop when it is out of our mouths.

Obviously, there are a few other bits and pieces but these are the main components needed to explain how the rebreather works.

As you can see from the diagram above, as we exhale, the exhaled gas is passed through the scrubber unit to remove the Carbon Dioxide from the mix. It then passes along where a solenoid injects oxygen to replace that which has been metabolised and makes the gas breathable again.

The amount of Oxygen injected is dependent on how you set the rebreather initially.

The Megalodon is a fully electronic closed circuit rebreather, which means it is run by the electronics. We set them to work by Partial Pressure of Oxygen (PO2) and usually tell the electronics to maintain a PO2 of 1.2 or 1.3. This is called the set point and, once this is set, the electronics can detect how much Oxygen to add to provide you the diver, with the optimum breathing mix for the depth you are at.

It is that simple!

Are Rebreathers the future of Diving?

 I believe that rebreathers are the future of diving but they are also the past, as CCR was around long before the advent of the Aqualung, single tank BCD and regulator set up.

The oldest known rebreather prototype was patented in France back in 1849 by Saint Simon Sicard (although the ideas were around from as early as 1808) and the earliest models were based on an oxygen reservoir and used sponges soaked in calcium carbonate to absorb the CO2.

Obviously things have become a little more refined and reliable since those days but the principles remain the same.

Rebreathers have amazing benefits over open circuit diving

Your mix is dynamic, so you are always breathing the optimum mix for the depth you are at. It is like having a nitrox/trimix mixing panel on your back as you dive. Obviously, this has an effect on your decompression obligations, reducing the time you have to sit on a line completing decompression stops.

The gas you are breathing is humid and warm rather than the dry, cold air from a compressed air scuba cylinder and regulator set up. Again, this is a benefit as it helps you to stay warmer and is less dehydrating than using the aqualung, which is great from a health and decompression point of view.

You don't use as much gas as you do on open circuit. Since the exhaled gas is recycled, not wasted, your limited gas supply will last much longer underwater, giving you better dive times. In fact, you are often only limited by the duration of the scrubber material in the can. However, remember that you must carry bail out gases and so, the dive plan must account for the gas you will need to ascend on open circuit completing any and all decompression obligations along the way.

In fact, the only real down side of the rebreathers is the initial set up cost to buy. They are still relatively expensive to purchase, although if you are an open circuit trimix diver, you can make the money back on difference in price to fill 3l cylinders with a Helium mix on the rebreather to filling twin 12s with the same mix.

Where in the past, rebreather diving has been something for Technical, mixed gas, decompression diver only, in recent years, a number of companies such as Poseidon and Hollis have been looking at opening it up to the recreational market by developing "plug and play" rebreathers for use down to 40m. While these can still set you back around £4000, it is hoped that the price will eventually drop and make it more accessible to the everyday scuba diver.



ISC has even brought out their "recreational" rebreather called the Pathfinder, which is a lovely little unit perfectly suited to the travelling diver.

So, while rebreather diving is still quite specialist at the moment, I believe this is one niche to keep your eye on. Who knows in a decade or so, you may be able to walk into a dive centre and say "I want to learn to Dive" and the Instructor will say, " sure...

on this?.....

Or this?...

scuba diving in cyprus

Scuba Diving in Cyprus: Zenobia Fish Life

The Value of a Check Dive

I want to go Diving! Great, let's do a Check Dive.


A Diver contacted Scuba Tech Diving Centre a couple days ago by email with a request to Dive the Zenobia with us.

I wrote back, as we always do, with the information about the dives, timings and prices and of course, the fact that, we always complete at least one shore dive as a check dive prior to Diving the Wreck. A prompt response quickly came back stating that this Diver was a very experienced Diver with 50 Dives under his belt, a PADI Advanced Open Water Diver and dived 6 months ago in Thailand, so why did he have to do a check dive before the Zenobia?

Immediately for a Dive Professional, this is when alarm bells begin to ring!

Since I have been involved in resort Diving, I have come to the realisation that, the best Divers, who have lots of experience and are fantastic in the water, are usually the ones who will expect to do a check dive and do not quibble over it.

Whenever I go diving somewhere new, I always expect the first dive to be a check dive, on the house reef normally to sort everything out before moving on to the better dives and I am an instructor with 20+ years experience and literally thousands of dives under my belt.

Now, when I talk about a check dive, I am talking about a proper Dive. I am aware that there are some Dive Centres in the world who do "take the Mick" and dump divers into 5m of water (or a swimming pool), go through some basic skills and pronounce them fit to dive, while rubbing their hands together and collecting the price of a full local dive. This is nothing short of an abuse of power and these centres should be named and shamed.

However, most Dive Centres around the world will give you a proper Dive as your Check Dive. Here at Scuba Tech, we go to a local Cyprus Dive Site with a depth of around 18metres, with swimthroughs and tunnels.  We have a good, long dive until Divers get cold or start to get low on air. Sometimes our check dives have been up to 90minutes in the water.

What is the point of the Check Dive?

The check Dive has a number of benefits to both the Dive Centre and the Diver.

From the point of view of the Dive Centre, it gives our instructors and Divemasters a chance to see you in the water on an easy bimble around a local dive site, that isn't too deep and get used to your diving style. We can get a feel for your air consumption so that on the Zenobia Dive, we know what air you will need to make an ascent and not bring you up too early or too late.

Also, it means that we have a chance to pre-empt any problems you may have Diving the Zenobia or the deeper Dives. If we spot anything that could cause problems or an equipment malfunction or leak, it is a chance to sort it in shallower water close to the dive centre, where we have all the tools required availble to us and not 1500 metres out to sea, on a boat with a limited spares and tool kit.

Remember, if something does happen on these deeper dives, it is your guide who has a duty of care to sort it out. It is imperative that we make these dives as safe as possible for you, the diver and all our members of the Scuba Tech Team.

For the Diver, a check Dive gives you the opportunity to get comfortable in a new environment. Everywhere is different, so you will need to perform a weight check and adjust accordingly. Many Divers who come Diving in resort think they need a lot more weight than they actually do, so this is an opportunity to get weight sorted and optimised before moving on to the bigger dives. Weighting is an issue very close to my heart and you can read more about my opinions on this in an earlier blog, "A weighty Issue".

Another good reson for a check Dive is Equipment.

If you are hiring equipment from your Dive Centre, it will likely be different to that which you have dived before and a check dive gives you the opportunity to get used to the controls, so on the more adventurous dives, everything is second nature to you. Also, if you find items such as the mask doesn't quite fit correctly and it is leaking, or maybe it needs a spot of toothpaste to stop it from fogging up, this can be remedied before the bigger dives. You don't want to miss seeing the Zenobia because of a fogged up mask!!!


Equally, if you have ever seen the baggage handlers at an airport, you will know that the bags get thrown about a bit. So, if you bring your own diving equipment with you, there will always be the possibility that some bits of your diving equipment could get damaged in transit  unless you are going to bubble wrap each item before you travel. Again, the check dive will allow you to ensure that everything works in tip top condition at a site that is close enough to the dive centre to be able to pop back and fix any problems.

Once we are on the transport boat to the Zenobia, there is no turning back and if the equipment doesn't work and cannot be fixed with the tools available, you lose a lot more than than the 20/30 euros you would have spent on a check dive.

So, for me, the Value of a check dive is the peace of mind that comes with knowing the bigger, more expensive dives will be that much more enjoyable and comfortable.  I will have the correct weights, properly working diving equipment that I have personally been able to verify and a dive guide who is comfortable diving with me, who has an idea of my diving styles and preferences and can tailor the dives I am going to do to my ability and preferences.

The Value of a Check Dive?... Invaluable!!

Sidemount Diving in Cyprus

New for 2013, we are offering Sidemount Diving Courses in Cyprus at Scuba Tech Diving Centre.

After a lot of research into the different sidemount diving systems available, I chose the Razor Sidemount System. There are a number of reasons for this choice but I will go into this a bit more at a later date. Today, I want to talk about Sidemount Diving itself.

Sidemount Diving originally comes from Cave Diving. It basically describes an equipment configuration that allows the Divers cylinders to be mounted alongside the diver, underneath the shoulders and along the side of the hips instead of the usual "tank on the back" configuration.

Now Sidemounting is gradually becoming more popular in mainstream diving and Technical Diving.




Why is Sidemount Diving so popular?

There are a number of reasons for the rising popularity of sidemount diving around the world. I think number one is the safety benefits of this configuration.

With Sidemount Diving, you can sidemount either one or two cylinders and two is actually the preferred method since it is gives more stability. This means you have more breathing gas to take on each dive with you, so you can stay longer and you have a redundancy gas supply in the event of an emergency.

Also there is greater accessibility to the valves and first stages of the regulators. If something goes wrong with these while they are behind your head on back mounted cylinders, it is a guessing game as to what has happened and you must run through pre-determined drills to ascertain what has happened, which valve needs shutting down etc. All the while precious gas is escaping. Cylinders mounted at the side of a diver can be seen and diagnosed immediately. Leading to a much faster fix.

The Sidemount Configuration is extremely Streamlined, since the tanks run under the armpits in line with the body. This streamlining helps to reduce water resistance which should allow the diver to travel through the water with greater ease, meaning less fatigue and a better air consumption.

I personally have found that the Sidemount Configuration with 2 cylinders is much more stable in the water. It is extremely easy to "trim out" and the way you can attach and detach the cylinders underwater and at the surface, makes life very simple when getting in and out of the water and passing through narrower areas on the dive itself.

So, in the opinion of this Diving Instructor, who has dived several different types of Diving Configuration, I can heartily recommend Sidemount Diving for Divers for Ease, Comfort, Better Trim and Safety.

Courses are available from Scuba Tech Diving Centre. The PADI Sidemount Specialty takes 3 days and costs just 300 euros (all inclusive). If you want to try before you do a Sidemount Course, we also offer a Discover Sidemount Diving experience.

For more information, please contact us at ScubaTech Diving Centre, Cyprus.

night diving cyprus

A weighty Subject...

For this blog, I am going to touch on a subject that is extremely important and yet quite often disregarded in the Diving World. Weighting!!!

Now, for those of you who know me, you will know that I believe correct weighting is the most important step in becoming a competent Scuba Diver. For those who don't know me yet, I believe that correct weighting is the most important step in becoming a competent Scuba Diver.

Why is Weight so important?

There are so many things to think about when you are Scuba Diving, why is making sure divers are correctly weighted so important? There are a number of reasons why... Let's look at a few

ARCHIMEDES PRINCIPLE

Think back to your first Scuba Diving Course. If you took the PADI Open Water Training, you will remember the very first thing on the very first page of your manual talks about Archimedes Principle.

An object placed in water is buoyed up by a force equal to the weight of the quantity of water it displaces



quizlet.com

Which, in diving terms means, that to be neutrally buoyant a diver must displace an amount of water equal to their weight. Neutral buoyancy is achieved by finding a balance between the weight of equipment and lead weights and the use of a Buoyancy Control Device (BCD).

When a Diver over weights themselves, much more gas is needed in the BCD to increase the displacement of water and make the diver neutrally buoyant. The deeper the diver goes, the more gas is required.

STREAMLINING

Ok, so now moving on to lesson number 2 in the course... streamlining. Have you ever tried running in a swimming pool. It takes a lot more energy than swimming through the water and this is a result of resistance.

Overweighting has 2 effects on the diver. Firstly, the diver's bottom half is dragged down by the weight around their waist, meaning their position is less like the swimmer through the water and more like the runner, increasing resistance and using more energy.

Secondly, the diver has to put more gas into the BCD making them bigger in the water and therefore not as streamlined. Again, this makes the Diver require more energy to make the Dive.

GAS CONSUMPTION

We already know that we are using more of our tank air to add to our BCDs to compensate for over weighting but look at those last comments with regards to energy used.

The more energy our bodies need, the more Oxygen our bodies must burn in order to provide it. This results in a higher heart rate and faster breathing rate, which means you will use your limited air supply much faster than a Diver who is correctly weighted and breathing normally would.

Weighting isn't the only factor in this but the amount of divers who have come to Scuba Tech telling us they use lots of air and require a 15litre cylinder is phenomenal. Once we have corrected their weight, not one of these divers have left here needing a 15litre. It is a BIG factor!

THE DANGER

So, we use a bit more air and we aren't perfectly streamlined, what is the big deal?

When we are overweighted, buoyancy becomes more difficult to control. We find ourselves having to add and release air from our BCDs much more often.

We are already breathing heavier and faster than we would, if we were correctly weighted.

Now, imagine something happens...

It isn't overly serious. For example, you get  bit of cramp in your calf muscle.

The added workload of solving the problem, means you start to breathe more heavily than you were before.

Your buoyancy adjusts with your breathing, you have to correct it and now you are dealing with 2 things at once. The increased work load and the heavy breathing means the level of Carbon Dioxide in your body is increasing, which your brain detects and triggers a faster heart rate and a need to breathe faster to reduce the level of CO2.

This can become a vicious circle, as your breathing becomes less efficient and shallower meaning you cannot reduce the levels of Carbon Dioxide and your brain keeps triggering the heart to beat faster and increase the breathing rate in response.
....and eventually your buoyancy goes out of control...

And this is where accidents happen. It is a downward spiral that started as a very simple problem but can easily compound into something much bigger and potentially life threatening.

Do Not misunderstand me, accidents happen even to those who are correctly weighted, but you probably wouldn't be starting out with an elevated breathing rate when you are correctly weighted and buoyancy is much easier to control, meaning it shouldn't become an added stressor.

Our Weights

To give you an idea of what we use...

Me
12l steel cylinder
Halcyon Wing with a Steel Backplate
Weighted Single Tank Adaptor
2kg lead weight
Brand new 6.5mm full wetsuit

Taking into account the steel backplate and the STA, you could say 6KG

Shell
10l steel Tank
Buddy BCD
6KG lead weight
10mm crushed Neoprene Drysuit with Thinsulate undersuit

So you can see, you do not need to plaster yourself to the bottom. Buoyancy and Trim will all be easier to control when you are correctly weighted.

Start dropping the weights, your breathing rate will reduce, which will naturally make it easier to sink (less air held in your lungs) and you will probably find you can take more weight off.

Diving the Zenobia in Cyprus with Scuba Tech Diving Centre and Nicky HIller

Welcome Divers

Well, since is the first blog on this platform, I guess my first message should be to say "Hello" and "Welcome to the Scuba Tech Blog".

Why don't I introduce myself a bit?

I am Peter Crane, a diving instructor with my own Dive centre based out in Cyprus, which is a beautiful Island in the middle of the Mediterranean Sea.

It hasn't always been this perfect a life though. I first learned to dive in the cooler waters of the UK at a little Inland Site, you may have heard of called Stoney Cove. I was a BSAC Diver through and through, having learned diving under the excellent instruction of Roundhill Sub Aqua Club. During the day, I was a Postie.  I might even have delivered your mail to you back in the 1990s.

Today, I have 20 years + diving experience. I am (and have been) an instructor with many different agencies including; PADI, BSAC, TDI, IANTD, ITDA, meaning I can teach many different types of Scuba. My weeks are so varied that one day I might be taking in a beginner for a Try-dive Experience and the next I am penetrating shipwrecks on my Megalodon Rebreather or Sidemount Diving through the small swim through caves.

I love scuba diving and try to continuously update my knowledge and qualifications. This is one reason I completed the GUE Fundamentals course in 2011 and am looking to take the TECH1 training soon.

This even reaches to dryland where I try to keep up to date with new equipment, new configurations and ideas. As a service technician for most scuba equipment (regualtors, cylinders etc) this is extremely important to me.

This blog is a way for me to share my passion for the underwater world, my thoughts and reviews of different equipment and types of diving and just general words of guidance that I have picked up over the years.

I hope you enjoy what is to come and let me know your comments and thoughts.

In the meantime, safe Diving to one and all

Peter