Dive Training Blogs
Scuba Professional: Column No. 4
“How Did That Get in There?”
Simon Pridmore looks at the common practice of filling scuba cylinders while they are standing in water and asks “Why?”
Anna is a new diver.
“I was on my ninth dive ever, about five minutes in and at a depth of around 12m when I realized that my air was not coming out smoothly. I couldn’t think why this should be. I had checked my pressure gauge on descent and it had shown 190 Bar. I switched to my octopus, but there was no difference. Soon the air became very thin.
I tried to stay calm. Everyone else was going deeper and swimming away from me. Then the air stopped completely. I held my breath. I looked around and there was my husband. He gave me his regulator and took me to the surface with him.”
Anna’s husband, an experienced instructor, takes up the story.
“I had checked my wife’s set up as usual before the dive. The pressure gauge was showing 190 Bar on the surface. A few minutes into the dive, I saw her hovering away from the reef in mid water, sensed something was wrong and swam towards her. She gave me a wide-eyed look and pointed at her regulator. I glanced at her gauge and saw it was at zero so I gave her my octopus and we went up together. “
“I was puzzled as to how a full tank could become empty so quickly. We were definitely no more than 10 minutes into the dive and there had been no O-ring blow out. After the dive, I removed the regulator and opened the tank valve. Nothing came out. Some instinct made me turn the tank upside down and, to everyone’s surprise, water started flowing out of the valve. It was fresh water!”
An Incredible Story?
It seems incredible that a scuba cylinder should be so full of water that a diver would only get a few minutes of air. Some might interpret the story simply as a misunderstanding on the part of a new diver with a supportive husband.
However, when I heard the story, it brought to mind something that I came across when I had a dive store in Guam. We used to conduct annual visual inspections on cylinders owned by local residents and were surprised to often find a few centimetres of water in the bottom of cylinders. This was always fresh water, not seawater. We made some enquiries and found that this is fairly common and comes from the almost universal practice in dive stores around the world of filling scuba cylinders while they are standing in a trough of water.
The fill whips, hoses that are clamped onto the valves of scuba cylinders to fill them, sometimes drop into the water trough between cylinder fills. When the wet clamps are then attached to the valve of the next cylinder and the airflow is turned on, the pressure of the air in the fill whip is higher than the pressure of the air in the cylinder and water droplets are driven into the cylinder.
Fill the cylinder several times and the amount of water inside accumulates until you have a little pool in the bottom. The moisture inside causes corrosion to build inside the cylinder too.
Bear in mind that I was in Guam, part of the USA, where a stringent system of cylinder inspections applies and is enforced by dive operators. The maximum length of time between inspections is 12 months so that means the water inside the cylinders had accumulated in less than a year.
In many places in the world where people dive, including the island nation where Anna’s dive took place, there are no regulations governing cylinder inspection, so it is possible that a cylinder could go for many years without anyone examining the interior.
Therefore, Anna’s story is not as far-fetched as it might initially seem. With her cylinder containing a large amount of fresh water, the volume of air in the cylinder was quite small so once she started her dive she used it up very quickly. The reading on her pressure gauge must have been dropping fast during those first few minutes of her dive but she did not notice.
Why Do They Do It?
Dive centres fill cylinders while they are standing in water for three reasons:
- To keep them cooler during the filling process, which generates heat, so they can fill them faster and so the air pressure inside does not drop so much when they cool down afterwards and they don’t have spend time hooking them up again to top them off.
- As a convenient way to wash salt off them post dive, and
- To protect the filler from harm if the cylinder explodes during filling.
All three of these reasons are the product of fuzzy thinking.
- Filling the cylinder in water has very little impact on the cylinder temperature, partly because the heat from the filling process is transferred to the water, which then gets warmer. Fast filling still causes the cylinder to get hot, despite the water bath, so it still has to be filled to 20 Bar or so beyond its rated pressure. This makes sure that the pressure is 200 Bar or more when the cylinder is cool. Otherwise divers will complain. The only effective way to stop a cylinder getting too hot while it is being filled is to fill it slowly and from a bank of large cool high-pressure air cylinders rather than directly from the compressor.
- Using the fill bucket to wash the salt off the cylinder is ineffective as all that happens is that the water the cylinder stands in becomes a little salty. A quick fresh water blast with a hose before the cylinder is taken into the compressor room does a much better job.
- Aluminium cylinders have exploded during the filling process in the past and when this has happened the consequences have often been fatal. However, an exploding cylinder is a bomb and no concrete trough is going to protect the person filling it. Instead it will just contribute more shrapnel to the explosion.
Having said this, those aluminium cylinders that exploded were made from a 6351 alloy containing lead and it was the presence of lead in the alloy that created the problems that caused them to explode. Since 1988, no aluminium scuba cylinders have been made using this alloy or with any alloy containing lead. The vast majority of scuba cylinders in service today worldwide, including all cylinders made by Luxfer and Catalina, the top two manufacturers, are made from an alloy called 6061.
Although, during annual inspections, cracks have occasionally been found in 6061 cylinders, none has exploded: ever! And there are millions out there.
No Need for a Bath?
It is worth noting here that not all dive centres that fill cylinders in water are ignorant and negligent. There are many dive centres that fully recognise the potential issues and take elaborate precautions to make sure their whips and cylinder valves stay completely dry during the filling process so that water does not get into their cylinders.
But if,
- The likelihood that a scuba cylinder will explode during filling is so remote,
- A water trough will not protect a filler if it does happen,
- The water trough is not an effective way of removing salt or reducing the cylinder’s temperature sufficiently and,
- The practice of wet-filling can allow water to enter a cylinder and lead to an incident such as Anna’s,
why do it at all?
Ironic, isn’t it, that, from day one, divers are constantly told always to leave some air in their cylinder at the end of a dive so that no water can get in! And yet ……
Read more from Simon in his latest release Scuba Professional – Insights into Sport Diver Training & Operations and his bestselling book Scuba Confidential – An Insider’s Guide to Becoming a Better Diver, both available from Amazon in paperback and e-book versions.
Blogs
NovoScuba’s Game-Changing Approach for Dive Store Owners: WE PAY YOU!
The diving world thrives on passion and adventure, but for many dive store owners, the financial and operational challenges can be as deep as the ocean.
NovoScuba, an emerging force in the diving world, is on a mission to transform this landscape for the better. With a revolutionary approach to dive store and training agency partnerships, NovoScuba is setting new standards for how dive stores can thrive while keeping their focus on delivering exceptional diving experiences.
A New Paradigm: NovoScuba’s Bold Mission
NovoScuba’s mission is straightforward yet profound: to disrupt the traditional dynamics between dive store owners and training agencies. Traditionally, dive stores have been subjected to substantial fees charged by training agencies, for membership, materials and certifications. These costs have often placed a heavy financial burden on store owners, cutting into their profits and limiting their ability to offer competitive prices to customers.
NovoScuba flips the script by offering a model where dive stores earn money, instead of paying high fees. Dive stores receive commissions for every student they register, and their certification costs are covered. This new model not only boosts profitability but also ensures clients get top-quality training at unbeatable prices.
Financial Upsides: Earn From Student Registration
NovoScuba’s approach is simple yet revolutionary. Dive stores partnering with NovoScuba can earn commissions for every student they enroll.
Here’s how it works: For every student enrolled through NovoScuba, dive stores receive a commission. Each student enrolled will receive their e-learning materials and certification credit included in their subscription. This arrangement is a significant departure from the traditional model, where dive stores often struggle to manage high overhead costs related to training fees and certification expenses.
NovoScuba’s approach ensures that dive stores can focus on what they do best—providing top-notch diving experiences—without being bogged down by excessive financial burdens, and the need to carry large stocks of materials.
Quality Training at a Great Price
NovoScuba stands out by offering high-quality, ISO certified, training that doesn’t break the bank, in fact our students will pay less than with most competing agencies. Clients benefit from top-notch education and safety standards at competitive prices. Dive store owners can confidently promote NovoScuba’s programs, knowing they’re offering fantastic training at affordable rates. This balance of quality and affordability helps dive stores build a strong reputation and attract more customers.
Your Brand is Your Business: NovoScuba’s Commitment to Showcasing Your Identity
At NovoScuba, we understand that your brand is your most valuable asset, and we’re committed to putting it front and centre. Unlike agencies that charge high fees to promote their own brand, we believe in investing in yours. With NovoScuba, you won’t be paying to advertise someone else’s logo alone, — our focus is on showcasing your unique identity. Certifications prominently feature your brand, as well as the training agency, reinforcing your store’s image and brand every step of the way. We’re here to support and elevate your brand, ensuring that your investment directly benefits your business.
Affordable Membership: An Investment in Your Success
NovoScuba’s membership model is designed with dive store owners in mind. Membership fees are kept low and include annual Pro member fees for your team. Payment can be made monthly or annually in your local currency, avoiding the hassle of exchange rate fluctuations. NovoScuba promises no exchange rate changes without a six-month notice, ensuring financial stability and simplifying budgeting. With a membership lasting 12 months from date of joining, you’ll enjoy a full year of NovoScuba’s benefits and support.
Streamlined Operations: Simplifying Your Workload
Handling administrative tasks can be a challenge, but NovoScuba makes it easier. We’ve streamlined certification procedures and reduced paperwork to help dive stores operate more efficiently. Certification processing is quick and straightforward, allowing more focus on teaching and customer service. Our system minimises bureaucracy by storing necessary forms in student profiles, reducing paperwork and administrative delays.
Crossover Made Easy
For dive stores looking to transition to NovoScuba’s model, the crossover process is designed to be smooth and hassle-free. NovoScuba provides support to ensure that the transition is as seamless as possible, helping dive store owners integrate into the new system with minimal disruption. Experienced dive Pros don’t need to undergo extensive retraining. Our crossover is designed to familiarise Pros with NovoScuba’s user-friendly platform, standards and course structures, and not to waste time and expense re-training in water.
With just a few simple steps, you’ll be ready to offer top-notch training through NovoScuba.
Comprehensive Business Support and Training Included in Your Membership
NovoScuba goes beyond financial benefits by offering experienced support and training. This value added service includes:
- Business Training: Optimise your operations with guidance on marketing, customer service, and best practices.
- Marketing and Promotion: Access resources to attract new customers and boost your store’s visibility. Enjoy cross promotions with NovoScuba to gain increased exposure.
- Ongoing Support: NovoScuba’s commitment to its partners extends beyond initial training and setup. The company offers ongoing support to address any issues or questions that arise. This continuous support ensures that dive store owners have a reliable resource to turn to whenever they need assistance.
Embracing Digital Natives: Instant Evolution and Continuous Improvement
NovoScuba’s digital-native approach is a game-changer. Leveraging cutting-edge technology, we ensure our services evolve and improve swiftly. Dive stores benefit from instant updates, the latest features, enhancements, and effective solutions, keeping them ahead of the curve. This continuous improvement helps dive stores stay competitive and deliver exceptional services. Whether it’s a new course update, additional marketing resources, or improved e-learning functions, NovoScuba’s digital infrastructure ensures that dive stores are always equipped with the most current and effective solutions. This continuous evolution not only helps dive stores stay ahead in a competitive market but also ensures they consistently provide top-quality services to their clients.
Why Is NovoScuba Doing This? – Fair Profit Sharing for Greater Access and Growth
At NovoScuba, we’ve taken a bold step by paying commissions to stores rather than following the traditional model of training agencies charging high fees. Our mission is to make diving accessible to everyone and to foster a growing community of new divers and continued education. By redistributing profits more equitably between stores and training agencies, we aim to create a more supportive and collaborative environment within the industry. We believe this approach not only helps individual stores thrive but also stimulates overall growth and innovation in diving. Our commitment to fair profit sharing reflects our dedication to the long-term health and expansion of the diving community.
Getting Started: Join the NovoScuba Revolution
Ready to revolutionise your dive store experience? NovoScuba is here to support your journey toward reduced costs, increased profitability, and enhanced operational efficiency. Get in touch with our team to learn how NovoScuba can transform your business.
For more information, email info@novoscuba.com or visit www.novoscuba.academy.
Blogs
Are you ready to become a Cave Diver?
By Marissa Eckert
What are the requirements to start cave diving? What do I need to do to be prepared for cave training? These are all questions I get asked by so many potential students. There are many options when coming up with an answer. The first option, and the easiest, would be to go the training agency website and look up the requirements to take the class. However, this leaves a lot open for interpretation and doesn’t mean you will necessarily be ready. Like anything, there always needs to be minimum requirements. But is that enough? Maybe for some people it is, but for most people it’s not.
So, what are the requirements?
TDI breaks cave training down into three different levels. Those levels are cavern, intro to cave, and full cave. To start cavern the requirements state that you must be 18 years old or 15 years old with parental consent, have an Open Water Certification, and a minimum of 25 logged dives. This doesn’t sound like much. So, what do I tell my students when they ask me? First, I find out if they are only interested in cavern or if they are interested in potentially progressing into cave diving. If they are interested in progressing into cave diving, I always strongly suggest they get comfortable with a dual configuration first. This configuration can be side mount, back-mounted doubles, or even a rebreather. The main things I tell everyone they need to have down are buoyancy, good trim position, the ability to hover in place motionless without moving their hands or feet, and good overall awareness. This means awareness of oneself and what your body and equipment are doing, but also total awareness of what is going on around you.
So, what does all this mean?
Many times I’ve had students show up thinking they had all these things mastered only to quickly realize they have a long way to go. Which by the way, is okay! After all, we all start somewhere and progress at different paces. The most important thing is to be open to feedback. But there are also ways to prepare yourself better. First and foremost, when starting down this route it is critical to find a good instructor. Take time to look up instructors, ask questions, interview them, look at their past students, look at what type of diving they are doing, and most importantly ask questions! Find out what techniques they use during class.
I have found that video recording students when they are struggling with something gives them a great perspective to see what they are doing wrong and helps them visualize and correct it. Does the instructor look good as a diver? Whether you like social media or not, the internet can be a great place for research. When looking at a diver they should look in trim, almost like they are laying flat on a table. In videos are they finning with their hands? Are their feet constantly moving? Are there things dangling below their body? All equipment and hoses should be extremely clean and contoured to the body.
The most important question to always ask during training is WHY? There should always be a why behind everything we do. And it should never just be because I said so. Make sure the instructor knows why they are telling you to do something a particular way. Everyone can always learn new ways of doing things, instructors included.
How can you truly prepare yourself?
A good idea is to record video of yourself or have a friend record you while diving. Send it to your instructor ahead of time, so they can give you feedback and let you know if there are things you need to work on. There is no certain number of years to be diving, or a certain number of dives to have, that says yes you will be ready. Every individual learns at a different pace. If a class is only offered in a minimum number of days with a maximum number of students allowed, be aware that this means less time practicing each skill. For this reason, you might be better suited doing one-on-one training or having a regular buddy take the class with you. This ensures you are comfortable with each other and familiar with each other’s habits in and out of the water, and that you get along!
The most important thing of all is to come to class with an open mind, a readiness to learn, and no concern with whether you will receive a card, but with a concern that you will learn to be a better, safer, more competent diver. I always tell my students safety is the number one most important thing in cave diving, but fun is a close second! Sometimes, it may not feel fun. Stop and ask yourself does this instructor have your best interests at heart? I know I certainly do. I want to go to sleep each night knowing that I gave my students as much knowledge as possible to make them safe and thoughtful cave divers.
With proper training, proper equipment, proper experience, and a proper attitude I think cave diving can be done very safely. I often joke that the most dangerous thing about cave diving is driving to the dive site!
To find out more about International Training, visit www.tdisdi.com.
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