The use of a single cylinder may provide enough gas to allow an ascent from recreational depths, but the volume of a single cylinder is simply not enough to allow an ascent plus decompression stops from greater depth. One tank means no redundancy and the words redundancy and technical diving go hand in hand (If you don’t need it, leave it. If you do, take 2). The use of twin cylinders/doubles or twinset is a way of providing this redundancy.

Sizes

A twinset is usually made up of two of the same sized cylinders with a regulator connected to each
cylinder. Twinsets made up of 12L, 15L, or even 18L cylinders are available but, for the majority of technical divers, twin 12L cylinders provide a good balance of weight and gas volumes. 10L twinsets aren’t uncommon with smaller ladies who are ‘light on fuel’ and don’t want to carry the weight of bigger cylinders.

 

Independent

Twinsets can be configured as independent or manifolded. Independent cylinders provide complete redundancy, as there is no link between the two cylinders. Thus, if one cylinder has a problem, the other is completely independent. However, as the two cylinders are independent, the diver has to switch from one to the other in order to balance the gas usage in the two cylinders (just like Sidemount diving). Whilst switching regulators should be easily within the skill set of a technical diver and should be a routine action, it can sometimes be forgotten when the diver is in the middle of a problem. We do NOT recommend independent cylinders.

 

Manifold

The other (better, more widely acceptable) option is to manifold the two cylinders together. This involves connecting the two cylinders at the valves by means of a manifold. On an isolation manifold the left and right cylinder valves allow the corresponding regulator to be shut off, leaving the entire gas supply (cylinder) to be used through the remaining regulator. The central valve, separates the tanks into two independent systems, each with its own first-stage and second-stage regulators, which can prevent a failure in one half of the system from losing the entire gas supply. This also has the benefit that the gas from both cylinders can be accessed from the primary regulator. The disadvantage is that, in the case of a problem, the diver must shut down the problem regulator, or isolate the two cylinders by means of the manifold, otherwise the gas from both cylinders will be lost. It is essential that a diver with a manifolded twinset can carry out a ‘shutdown’ to prevent the complete loss of their gas. As a twinset diver you need to be able to do shutdowns with your eyes closed (literally in some situations).

 

Final thoughts

10 years ago most tech divers, especially cave divers would be seen with twinsets. This has changed over time. Rebreathers are almost commonplace now and Sidemount has made a huge entrance in the market.Doubles are quite expensive to put together and a bit heavy to carry outside of the water. But if your back can handle a little bit of extra weight, you will not be disappointed. The added weight works for you when diving a drysuit. The balance is brilliant. Streamlining easy (everything has its place). No HAVING to change regs constantly. And a big plus – modular dive systems. Upgrade parts, not entire setups.

Recommended settings

• 1080p 60fps
• Turn Spot mode OFF to let the camera evaluate the entire scene for better exposures.
• Turn ProTune OFF, as this feature requires more work when editing in post.

 

How to correct color

Where?	Fix
Ocean (blue tint)	Red filter
Fresh Water (green tint)	Magenta filter

If you already have the footage you can color correct using your favorite editing program. GoPro offers the CineForm editing software as a free download from their website. This software does wonders! It’s free…go get it!

When editing

There are a few simple steps you can employ using editing software to make your footage look more like the way you intended when you captured it:

• In the white balance tool, move the slider slowly from blue towards yellow until it looks right to your eye. You are warming up the image by lowering the color temperature.
• Slide the tint tool from green towards red/magenta.
• Look at the highlights in your image to ensure you have not gone too far and tinted them pink. Continue to adjust each slider until it looks right.
• Increase the contrast.
• Shift the exposure slider to brighten up the shot.
• Review the entire shot sequence to ensure that your corrections appear consistent throughout the entire range of light in the shot.
• Work in short clips for color correction. Attempting to correct a long sequence might take significant system memory and time.

Get closer

GoPros are designed to shoot the widest angle possible in order to catch all the action. When you’re underwater that’s great, until you want to get a close-up of something. Steadily approach your subject until you’re almost on top of it. That should get it all in shot!

How to steady your shots

• Breathe deep and swim slowly
• Pan the camera very slowly with deliberate moves
• Use a tray with built in handles
• Use an extension pole (selfie stick)
• Use optical stabilizing features in editing programs that smooth out some jerky movements

Fogging up

Operating a battery-powered device underwater generates heat; seal that in a housing and plunge it into cold water and it’ll fog up pretty quickly, ruining your footage. You can buy special anti-fog inserts OR use chamois leather (shammy – that you use to wash your car with), cut out small squares and drop them inside the housing to absorb any moisture. Wash it once and dry it in a low-heat oven to increase its effectiveness even more.

 

Article by Jacques Bezuidenhout (co-owner of The Scuba Shop) – PADI MSDT, Rebreather Instructor, Cave Diver

Welcome to the Dark side

Cave diving is an activity not every diver would enjoy. A cavern is generally defined as the first part of a cave, when you can turn around and still see the exit. The cave starts when you swim around a bend, and you cannot see daylight in any direction. In this article I’ll refer to both types of diving as “cave diving,” because cavern diving is where it all begins for those of us drawn down into the earth— to places so few people will ever see.

To fin along a path less trodden is part of the attraction, but there are many other reasons divers explore caves. With no sunlight to sustain bacteria and no water movement to hold silt in suspension, visibility can reach astonishing distances — up to 60m in some caves. In an enormous chamber, divers may be able to see another tiny pair of divers and their lights all the way over on the other side, the water so clear it is literally invisible — like floating in space. Some caves actually look like the surface of the moon, with pale white limestone carved into strange, unearthly shapes. In other caves the water moves along rapidly, and divers swim against the flow going into the cave and, if the passages are large enough, fly along with the flow heading out. Dives like these are truly remarkable experiences. On the other side of the coin, sometimes the water flows inward from the entrance, and divers need to be extra cautious to turn around with enough remaining gas to swim against the flow and still make it out with gas in reserve for safety. (Planning these kind of dives are a big part of your cave diving course)

To the trained eye, caves offer as much variety as exists between different shipwrecks or different reefs. Some caves have white walls, some dark walls that eat your torchlight, and some have stripes from alternating seasons that either send dark water into the cave or clean water to flush it out. Because they are most commonly made of limestone, many caves have beautiful fossils embedded in the walls. Strange animals live in caves. Having adapted to the cave environment over eons, they may lack pigmentation and appear pale white; many are blind with extra-long feelers to detect food in the complete dark.

In the same way ocean divers often develop a store of knowledge over time, so too do cave divers, and conversations leading up to and following dives are as animated as those on any dive boat. In short, cave diving offers an opportunity to visit unique environments with adventure aplenty and as part of a dive group that shares a passion.

How to Start Cave Diving

The path from recreational diver to cave diver is now clearly marked. First, we start in caverns and learn the basics of safe cave diving. These include the five golden rules, which cover gas planning, maximum depth, adequate lighting, marking the trail and the need for training. New skills introduced at this time include finning techniques such as the frog kick. This kick can minimize the risk of stirring up silt, which could disorient divers and cause them to lose their way.

After the cavern diver course, we usually go dive caverns as much as we can until we start shining our torches around the bend and thinking, “I wonder what’s down that passage.” The next level of training is usually an intermediate phase in which divers start diving with more than one cylinder and practice running line. Several types of reels are available today, and divers should learn to use the ones they will be using after the course.
Some caves have a “gold line” from the entrance through the main passage; some require the lead diver to lay line beginning some distance beyond the entrance to prevent curious novices from following the gold line into the cave. This training level usually comes with some restrictions so we don’t go too fast too soon: “no leaving the main line to explore side passages” or a gas restriction such as “no diving beyond a third of a pair of doubles,” for example. Different training agencies have different restrictions, but they are all intended to encourage new cave divers to gain experience before moving even farther into the earth.

After making a number of cave dives, which seem incredibly adventurous, you’ll be ready for a course to become a “full-cave diver.” This level of training includes learning to dive complex caves, running short lines (called “jumps”) and using line markers such as arrows and “cookies” to record information such as who is still in the cave and which is the shortest way out. Each level of diving increases the amount of potential anxiety divers may experience, so they should gradually add to their experience before progressing. (It is possible to do cavern diver – full-cave diver consecutively. This usually depends on your level of experience and how well you perform during your course)

Improved Safety

In the early days of cave diving, fatalities were significantly more common than they are thought to be today. Research at DAN examined more than 300 American cave-diving fatalities over a 40-year period and found that modern approaches to cave-diver training, probably coupled with more regulated access, appear to have stemmed the tide of young, untrained and ill-equipped divers drowning in caves. Today it would be difficult to find a recreational diver who does not know you need special training to safely dive in caves. With this said, if we look at South African cave diving fatalities they were more common in the 80’s and 90’s and mostly occurred in Wondergat where depth and narcoses played a big role every time.

With that training comes the expectation of suitable gear, and such gear usually costs a bit more than the equipment used for ocean diving. Many of us have been diving for years before we get into the darker side of diving, as cave diving is affectionately known. Considering the experience, the cost of the gear and the expense of the additional training, today’s cave diver may be a few years more seasoned and a bit more cautious. In general, we also have high-quality, well-maintained gear and, above all, advanced training.

One of the added benefits of getting trained as a cave diver is that the skills developed along the way carry over into the rest of our diving. Many of us change the way we fin even when diving reefs so we don’t throw pressure waves down onto the wildlife. We feel more comfortable carrying an extra cylinder and regulator when making deeper dives, and our gas consumption tends to drop as we improve our trim and buoyancy control. This means we use less gas on average, so our dives become less physiologically demanding.

 

Cave-Diving in South Africa

• Komati Springs – Flooded mine with a vast network of shafts
• Wondergat – Deep caverns
• Bobbjaansgat – Expedition dive
• Wetsgat – Must be dived on Sidemount
• Boesmansgat – Expedition dive

 

Get trained

There are only a handful of cave diving instructors in South Africa. You will be able to do a cavern diving specialty course with an instructor that is a full-cave diver (there are more of those around than full cave instructors). Before signing up for a course, try to contact someone who was trained by the instructor you’re considering. ALL instructors claim they are ‘the best’. This isn’t some reef fish weekend specialty. You don’t want an instructor who takes shortcuts and passes you for the ‘cert’. DO YOUR RESEARCH before you book a course. The value of a patient instructor when you’re heading into the overhead environment cannot be overestimated. Don’t be afraid to let your instructor know if something is beyond your comfort zone. Progress cautiously, gradually gaining experience, and above all, remember: Anyone can call any dive at any time.

If this sounds like a path you would like to follow, the best advice is to locate a good instructor. CONTACT US

 

Cave diving equipment – start today

If you are new to diving but your goal is to one day become a cave diver it’s a good idea to buy the right equipment from the start – gear that will be suitable for the cave environment.

 

Keep the following in mind:

• Fins – Open heel fins that are not: Split fins, free diving fins.
• BCD – Buy a backplate/wing BCD from the start. They can be used for both sport diving and technical diving (jacket style BCD’s CANNOT be used for technical diving)
• Regulator – DIN is the tech standard. (You can easily convert a DIN reg to yoke)
• Torch – If you need a torch for night diving, purchase a torch that can one day be used as a backup light in tech diving.
• Dive computers – Consoles may be great on reefs but they’re too bulky for tech diving.

 

Article by Jacques Bezuidenhout

1. Dive tables are static. Dive computers are constant

Dive computers provide constant tracking of decompression status. The purpose of using a dive computer is to make diving safer and more enjoyable. It will give you more freedom on your dive because you will be able to constantly track no stop times, depth, temperature etc.

As a young man I had very opinionated views regarding life – I knew what was right and what was wrong, I knew who to vote for and who not to vote for, I knew how to manage money and I also knew that my parents were wrong.Life was a simple canvas – black and white with a very thin grey line down the middle. As I grew older my parents’ intelligence increased exponentially, my perceived monetary skills disappeared, together with what meager funds I had, and the grey line became a lot wider…

Technical diving is the exact opposite. As a newbie diver I ran around from Instructor to Instructor and centre to centre trying to get the best price and the quickest training, trying to fill my logbook with quantity and my wallet with certification cards. Diving was a grey canvas with a thin black line on the one side and thin white line on the other… anything was ok and everything worked. As I progressed with technical training from longer to deeper dives and from that to caves and eventually to Rebreathers, I realized that technical diving is white or black – it’s either done the right way or not. The grey line down the middle of my tech canvas is so thin it almost disappears…

Tech diving is disciplined diving, not the adrenaline fueled rush of a surf launch or the imaginary fear inducing thoughts that go through your head when you see shapes moving fast in murky waters, its cold calculated planning and precise execution. There is no place for silly fears or unthinking actions.

Equipment is either the right gear, and correct configuration, or just forget it. The grey line is much, much thinner and the canvas is black and white only.

Equipment configuration has been “perfected” by tech divers pushing the envelope – in some cases pushing too hard and losing their lives – the quality equipment needed has been developed by divers through the years diving on the edge, sometimes building their own gear, fixing,  complaining to manufacturers, altering gear and configurations until only the best remained. This is the equipment and configuration the modern tech diver has access to today. This is the gear that recognized technical brands sell today.

Choosing the correct gear is simple; there is a very limited choice of quality technical gear and an even smaller choice of configurations! Trying “something new” simply does not work when it gets to this level! (Unless you are very experienced!) You either Do It Right (DIR) or don’t do it at all.

Technical training procedures and standards has developed based on mistakes – simply put if someone died a rule was put in place to prevent the next diver dying, the same principles are still used by recognized training agencies when they decide to  change their training standards or training methodology.

Tech instructors MUST have experience – if your Instructor suddenly becomes a Tech instructor and you have never seen him in a twinset before, remember that it’s either black or white – there are no grey areas here!

Article by Peter Herbst: PADI Course Director, IANTD Instructor Trainer, Rebreather Instructor, Cave Diver

So you want to start Tech diving and don’t know where to start…or what to do…or how to go about it…3 easy steps.

Step one

Have access to funds, lots of funds..Tech is expensive, good gear is expensive (and no, you cannot use that reg you bought on “special”) and good training is expensive, the old adage of “you get what you pay for” is very true…Some people shop price and some people shop quality – Tech is definitely a possibility for the latter but should not be attempted by the former, having said that just buying the most expensive gear is not the answer either!

 

Step two

Ask around, not your buddy with 5 dives more than you….speak to different Tech Instructors, like your Instructor…and trust him/her. Then listen to what they say…you are paying a lot of money, not just for the training but also for the advice (see step one!)  while doing training – and one sure way of really peeing your instructor of is to buy exactly what he told you not to….

 

Step three

Dive, dive a lot, fresh water, salt water, swimming pool…doesn’t matter, live in the water and become VERY familiar with equipment malfunctions and get to know yourself underwater. Too many divers are chasing depth too soon in their diving careers, they either lose nerve or worse- lose their lives…and don’t make a mistake people do die scuba diving. You might just not always hear about it!!

 

Trimix problems

Trimix takes you deep, lessens the effect of narcosis by replacing the gas that causes the narcosis. The most notable and written about effect is of course High Pressure Nervous Syndrome (HPNS) but since I’ve NEVER been THAT deep you have to read what Nuno has to say! Then we get Isobaric Counter Diffusion ( ICB) – this happens on deeper dives ( 80m +) when switching gas from a high END to a lower END ( Equivalent Narcotic depth) on the way up – not good…this can cause a “bend” in your middle ear and can lead to extreme vertigo and nausea…mmm…read what Don has to say about that one!!

Other problems are associated with the depth you are diving on the trimix– wrong gas switches (death…), rapid accents (death…) and out of air (death…).

The biggest trimix problem (and the easiest to overcome) is lack of proper training and experience. Going to deep too soon without the training and experience may lead to undesirable consequences.

Peer pressure can push you to places you should not be – and way outside your comfort zone – walk away from a dive you feel uncomfortable about, take baby steps in gaining experience and live to dive another day!

 

Why did I start Tech diving?

Don’t know why I started Tech diving in particular – I just met the right people at the right time I suppose!

I read and heard the stories of Paul Verhusel that died in Sterkfontein and later Deon Dreyer that went missing in Boesmans. I met Nuno when doing my DM course and chatting to him found out that he was in some way or another involved with both these tragedies, then met with Don and he introduced me to Nitrox and basic decompression diving – suddenly my limit was not just a plastic dive table but whatever I chose it to be – my depth was where I wanted to go and not some limit set by someone I never even heard off…and then I bought “the Darkness Beckons” by Martin Farr…and THAT was the end…

 

Article by Peter Herbst (co-owner of The Scuba Shop) – PADI Course Director, IANTD Instructor Trainer, Rebreather Instructor, Cave Diver