Avelo

1. How does the Avelo System work, and how is it different from standard scuba?

The Avelo System is buoyant at the surface. When divers need to descend, the operator pumps water into the water chambers which makes the Hydrotank less buoyant. If the operator wants to become more positively buoyant, they purge water out of the water chamber.

The advantage of this approach to buoyancy control is that the buoyancy is ultra-stable. Once the Avelo System establishes neutral buoyancy it can go up or down in the water column thousands of meters (in theory) with no change to buoyancy. Even when the Avelo System is somewhat positively or negatively buoyant, it maintains the same level of buoyancy as it changes depth.

This contrasts starkly with a buoyancy system that relies on an air pocket (a.k.a. BCD). An air pocket is very sensitive to ambient pressure. When a diver ascends slightly, the air pocket expands, and buoyancy increases. This puts the diver on an ascent trajectory. Unless they release air from the BCD, this air pocket will continue to expand and will quickly lead to an uncontrolled ascent.

The same process is true for a small descent. The result is that the diver must be on-guard the entire dive. In other words, neutral buoyancy when relying on an air pocket is unstable. We are so used to unstable buoyancy that we can’t imagine an underwater world where a diver just swims to the depth they desire, and then simply stop swimming. In today’s scuba world, depth change equals buoyancy change.

The Avelo System is a wearable lightweight buoyancy control device that contains the air you are breathing. It breaks the equation above. With Avelo depth change does not equal buoyancy change.

The Avelo System’s main component is the Hydrotank, a lean scuba tank with a flexible inner bladder. Compressed air (or another breathing mixture) is stored in the bladder. When the diver enters the water with the Avelo System, they float because their gear is buoyant. When they are ready to descend, they turn on the pump for 30-60 seconds. As the water chamber of the Hydrotank is filled, they become less buoyant until they reach neutral buoyancy. They turn the pump off.

Next, they swim down. Their neutral buoyancy is stable even if they go deep or are with thick wetsuits. It is a sensation that does not exist in scuba today. To fine-tune their buoyancy, divers use their breathing. This is how buoyancy was intended to be managed by using a BCD.

However, since the BCD is a very large air bubble compared to the tidal volume of the lungs, there is a substantial difference in how BCDs operate versus the Avelo System.

Think of diving with a BCD as having a large air bubble riding on a much smaller air bubble that changes volume constantly (i.e., breathing). The BCD throws off the diver’s neutral buoyancy throughout the entire dive. Once this large air bubble is eliminated with the Avelo System, buoyancy control using one’s lungs becomes intuitive and makes even novice divers instantly present the buoyancy control skills of a divemaster. It shortens the learning curve of every other skill in scuba and accelerates buoyancy control mastery by orders of magnitude.

With this perfect buoyancy, divers can move freely in all directions. When they stop swimming, they stop moving. As gas is consumed, the Hydrotank becomes lighter, so the diver pumps more water into the tank. A diver would typically use the pump 2-3 times in a dive, one minute each time.

On the water's surface at the end of the dive, the diver opens a purge valve to remove all water from the Hydrotank. The reduced weight makes the system even lighter which is beneficial for exiting the water.

Our certification program provides in-depth information into how the Avelo System works and teaches how to dive Avelo.

2. Is the Avelo System like a rebreather?

No. The Avelo System is a self-contained, open-circuit underwater breathing and buoyancy control apparatus. The Avelo System is simpler, lighter, safer, and more efficient than standard scuba. It is everything you love about scuba: simplicity and freedom, just much better.

Rebreathers recycle your breath by absorbing CO2 and replenishing the oxygen. Obviously, this is a gross simplification of how rebreathers work but is sufficient for the purpose of this answer. Rebreathers are a wonderful technology and some of us are very experienced with them.

However, in terms of buoyancy control, rebreathers are the opposite of Avelo. A rebreather has a counter lung that expands when you exhale. This means that you cannot control your buoyancy with breathing and must rely 100% on the bubble inside the BCD. Buoyancy control with a rebreather is far more challenging than with standard scuba.

With Avelo, buoyancy control using the diver’s lungs is so intuitive and simple that divers on their very first dive exhibit buoyancy skills equivalent to those of divers with 100 dives on standard scuba.

The other big difference between Avelo and rebreathers is weight. Rebreathers by themselves are not light and require the use of bailout tanks.

The third big difference is cost. Rebreathers are notoriously expensive and require considerable care and maintenance. The Avelo System cost is competitive with standard scuba equipment while providing a superior experience.

3. Is the Avelo System safe?

Superior buoyancy control means safer diving. Stable neutral buoyancy means that the diver is less anxious, less prone to develop problems, and has considerably more time to respond to evolving situations. Imagine an underwater world where there is no such thing as a rapid, uncontrolled ascent or descent. That is what the Avelo unit offers.

Our Hydrotanks are DOT and CE approved specifically for their intended use in saltwater, pool water, and hazardous liquids or other environments. They are manufactured to a very strict ISO standard which is far more restricting than any aluminum or steel scuba tank produced today.

The Avelo System is sophisticated in its working principle but relies on simple and very reliable components. Just like with standard diving equipment, our equipment is tested for safety and includes annual inspections and normal hydrostatic testing schedules.

Our course teaches divers how to safely operate the equipment and includes pre-dive safety checks, maintenance information, and how to handle malfunctions.

Result of gear malfunctions	Standard Scuba	Avelo
Uncontrolled ascent	Dropping a weight pocket or a "stuck" power-inflator button will undoubtedly launch a diver to the surface unless they are professionals or otherwise extremely experienced. The change in buoyancy is very fast and a diver can find themselves on the surface in a matter of 10-20 seconds.	Not relevant. There are no rapid buoyancy changes with the Avelo System under any scenario. The only scenario where the diver becomes positively buoyant is if there is a water leak from the high-pressure hydraulic hose that connects the pump to the Hydrotank. Even in this case, a leak is so slow that the diver will have 15-20 minutes to address it after they notice the leak.
Uncontrolled descent	This is caused by a ripped BCD bladder or ripped or broken BCD deflator tube especially when coupled with overweighting. Under any one of these scenarios, a diver is at serious risk of sinking or swimming hard to the surface. If they decide to drop their weights, it could lead to rapid ascent if some air is trapped in the BCD. Bottom line: the standard scuba system is very prone to rapid buoyancy changes.	Not relevant. There is no scenario with the Avelo System that a diver can become so heavy that they can’t easily swim to the surface. If the pump or battery malfunctions (same likelihood as a ripped or broken BCD), there is NO CHANGE IN BUOYANCY. The diver maintains neutral buoyancy for at least 15-20 minutes. Bottom line: the Avelo System can’t develop the same rapid buoyancy changes that we are all used to as standard scuba system divers. This difference allows for significantly longer timeframes to stop, breathe, assess, consult with your buddy, and react. It’s a whole different world of safety.
Rapid loss of air	An o-ring failure, HP or LP hose failure, or second or first stage problems can lead to rapid loss of air. Obviously, a high pressure failure is worse.	Same. The Avelo System works with the same regulators used today. The only difference is that our system uses a DIN adapter. One of the most common questions we get is: what happens if the bladder fails. The internal bladder can handle a pressure that is 4X larger than today’s standard scuba tanks. The Avelo experimental dive team intentionally punctured, ripped, and cut open the internal bladders during product validation procedures. The result is that a small amount of air transfers to the water side. Water does not enter the bladder because air pressure keeps it out. Air does not escape the Hydrotank just because the bladder is compromised, and it is not an emergency. Bladders are inspected and tested just like standard scuba tanks. The likelihood of this type of failure is equal to the likelihood of a scuba tank failing, except that the failure of a scuba tank is catastrophic whereas bladder failure is not even an emergency.

Result of gear malfunctions

Standard Scuba

Avelo

Uncontrolled ascent

Dropping a weight pocket or a "stuck" power-inflator button will undoubtedly launch a diver to the surface unless they are professionals or otherwise extremely experienced. The change in buoyancy is very fast and a diver can find themselves on the surface in a matter of 10-20 seconds.

Not relevant. There are no rapid buoyancy changes with the Avelo System under any scenario. The only scenario where the diver becomes positively buoyant is if there is a water leak from the high-pressure hydraulic hose that connects the pump to the Hydrotank. Even in this case, a leak is so slow that the diver will have 15-20 minutes to address it after they notice the leak.

Uncontrolled descent

This is caused by a ripped BCD bladder or ripped or broken BCD deflator tube especially when coupled with overweighting. Under any one of these scenarios, a diver is at serious risk of sinking or swimming hard to the surface. If they decide to drop their weights, it could lead to rapid ascent if some air is trapped in the BCD. Bottom line: the standard scuba system is very prone to rapid buoyancy changes.

Not relevant. There is no scenario with the Avelo System that a diver can become so heavy that they can’t easily swim to the surface. If the pump or battery malfunctions (same likelihood as a ripped or broken BCD), there is NO CHANGE IN BUOYANCY. The diver maintains neutral buoyancy for at least 15-20 minutes.

Bottom line: the Avelo System can’t develop the same rapid buoyancy changes that we are all used to as standard scuba system divers. This difference allows for significantly longer timeframes to stop, breathe, assess, consult with your buddy, and react. It’s a whole different world of safety.

Rapid loss of air

An o-ring failure, HP or LP hose failure, or second or first stage problems can lead to rapid loss of air. Obviously, a high pressure failure is worse.

Same. The Avelo System works with the same regulators used today. The only difference is that our system uses a DIN adapter.

One of the most common questions we get is: what happens if the bladder fails. The internal bladder can handle a pressure that is 4X larger than today’s standard scuba tanks. The Avelo experimental dive team intentionally punctured, ripped, and cut open the internal bladders during product validation procedures. The result is that a small amount of air transfers to the water side. Water does not enter the bladder because air pressure keeps it out. Air does not escape the Hydrotank just because the bladder is compromised, and it is not an emergency.

Bladders are inspected and tested just like standard scuba tanks. The likelihood of this type of failure is equal to the likelihood of a scuba tank failing, except that the failure of a scuba tank is catastrophic whereas bladder failure is not even an emergency.

Uncontrolled ascent

Standard Scuba

Dropping a weight pocket or a "stuck’ power-inflator button will undoubtedly launch a diver to the surface unless they are professionals or otherwise extremely experienced. The change in buoyancy is very fast and a diver can find themselves on the surface in a matter of 10-20 seconds.

Not relevant. There are no rapid buoyancy changes with the Avelo System under any scenario. The only scenario where the diver becomes positively buoyant is if there is a water leak from the high-pressure hydraulic hose that connects the pump to the Hydrotank. Even in this case, a leak is so slow that the diver will have 15-20 minutes to address it after they notice the leak.

Uncontrolled descent

Standard Scuba

This is caused by a ripped BCD bladder or ripped or broken BCD deflator tube especially when coupled with overweighting. Under any one of these scenarios, a diver is at serious risk of sinking or swimming hard to the surface. If they decide to drop their weights, it could lead to rapid ascent if some air is trapped in the BCD. Bottom line: the standard scuba system is very prone to rapid buoyancy changes.

Avelo

Not relevant. There is no scenario with the Avelo System that a diver can become so heavy that they can’t easily swim to the surface. If the pump or battery malfunctions (same likelihood as a ripped or broken BCD), there is NO CHANGE IN BUOYANCY. The diver maintains neutral buoyancy for at least 15-20 minutes.

Bottom line: the Avelo System can’t develop the same rapid buoyancy changes that we are all used to as standard scuba system divers. This difference allows for significantly longer timeframes to stop, breathe, assess, consult with your buddy, and react. It’s a whole different world of safety.

Rapid loss of air

Standard Scuba

An o-ring failure, HP or LP hose failure, or second or first stage problems can lead to rapid loss of air. Obviously, a high pressure failure is worse.

Avelo

Same. The Avelo System works with the same regulators used today. The only difference is that our system uses a DIN adapter.

One of the most common questions we get is: what happens if the bladder fails. The internal bladder can handle a pressure that is 4X larger than today’s standard scuba tanks. The Avelo experimental dive team intentionally punctured, ripped, and cut open the internal bladders during product validation procedures. The result is that a small amount of air transfers to the water side. Water does not enter the bladder because air pressure keeps it out. Air does not escape the Hydrotank just because the bladder is compromised, and it is not an emergency.

Bladders are inspected and tested just like standard scuba tanks. The likelihood of this type of failure is equal to the likelihood of a scuba tank failing, except that the failure of a scuba tank is catastrophic whereas bladder failure is not even an emergency.

4. When the pump is on, the pressure I read will rise. How do I monitor my pressure?

The Avelo System is compatible with your existing dive gauge technology (analog or digital). The same rules of diving for gas management apply to the Avelo System. The physics behind the consumption of gas allows the performance of gauges to operate in the same manner. Our certification program provides more detail and teaches divers how to easily monitor their air pressure with the Avelo System.

5. What is a compressible volume, and what is its significance?

The compressible volume in diving is a term used to describe the type of gear that is sensitive to ambient pressure. For example, the BCD contains a large air bubble. It is very sensitive to ambient pressure and expands or compresses every time you change depth, which changes your buoyancy.

Another compressible volume is the exposure suit. Wetsuits are far less sensitive to pressure changes because the neoprene they are made from is a closed-cell foam. Think of it as a lot of tiny bubbles held together by a strong rubber shell. This and other factors severely limit the compression of wetsuits due to pressure. The Avelo Experimental Dive Team experimented with hundreds of wetsuits of different designs, sizes, types, styles, thicknesses (0.5mm to 10mm), configurations (multiple layering), color patterns, etc. Avelo works with all of them equally.

Another type of compressible volume is a dry suit. Divers who regularly use dry suits are used to carrying a lot of weight. As a result, managing the buoyancy of both air pockets (BCD and dry suit) is more challenging. The Avelo System eliminates the BCD and allows dry suit divers to carry significantly less weight. While the diver still must manage the buoyancy of the drysuit, we found that diving Avelo with a dry suit requires far less weight than with a BCD.

The significance of the compressible volume is that it destabilizes neutral buoyancy. The larger it is, the more sensitive it is to depth changes and the harder neutral buoyancy is to control. The Avelo System significantly reduces the amount of compressible volume. This is the magic behind our superior neutral buoyancy.

6. Is the buoyancy control feature automated?

No. The Avelo System is manual. Neutral buoyancy with the Avelo System may feel as if it is automatic at times because it is very stable, and this form of stable neutral buoyancy lasts for long periods.

However, the system is not automatic, so the diver has complete control.

7. How would I perform an emergency ascent using the Avelo System?

Emergency ascents are part of Avelo training and are much more controlled than when diving a BCD. To gain buoyancy you open the purge valve and allow all the water out. The purge valve is mechanical and not tied to the pump or any electrical component. If you chose to purge all the water out, it is an intentional action (just like choosing to inflate a BCD). You will gain buoyancy and will begin to ascend. If you needed to ascend even faster, you could kick (the same as you would with a BCD if needed). This is practiced in every Avelo training program from basic to professional.

We practice every potential malfunction of the system, just like you should practice every failure mode in standard scuba. BCDs can (and do) tear. Other common failures of BCDs include leaking of the inner bladder, the power inflator getting stuck and inflating the BCD uncontrollably, and weight buckle releases leading to uncontrollable ascents. In the same way that BCD failures are practiced, we practice all potential malfunctions of the Avelo System during the certification program. All potential malfunctions of the Avelo System have been thoroughly tested and demonstrated and all can be managed with ample time to resolve any situation.

The Avelo System does not allow uncontrolled ascents. When you perform an emergency ascent with a BCD, the likelihood of uncontrolled ascents due to equipment failure provides a safety concern. With the Avelo System, an uncontrolled ascent is not possible, so the safety margin is high. Releasing water to add positive buoyancy to your system is always a manual control.

8. How do I control my buoyancy using the Avelo System?

The magic of diving Avelo is that it allows for superior buoyancy control by using breathing and lung control. The philosophy of buoyancy control is like the use of the BCD in that the buoyancy system allows a diver to reach a setpoint, which is typically referred to as neutral buoyancy. A diver who is neutrally buoyant and breathes normally and comfortably will experience slight undulations in their buoyancy due to the inhalation-exhalation changes of the volume in their lungs. The better a diver can control their lungs, the better and safer the diving experience is.

The Avelo System is used to bring the diver into this neutral buoyancy setpoint by adding water when a larger downward force is needed, or by purging water if more upward force is needed. The Avelo System is not used to raise or lower a dive in the water column. It is used to achieve the setpoint of neutral buoyancy. From that point forward, the diver effortlessly controls their buoyancy with lung control. Divers who learned how to dive Avelo master lung-control very quickly and even find this skill to significantly improve their standard scuba experience.

When diving with a BCD, the air bubble in the BCD continuously interferes with the above-mentioned setpoint. Every change in depth leads to a buoyancy change which forces the diver to either add air or remove air from the BCD so the setpoint can be reached again. There is also a delayed feedback effect from the time the depth change occurred to the time the change in buoyancy is felt. This leads to divers reacting too late to the depth change. These disruptions to the setpoint do not exist when diving Avelo. The setpoint remains constant regardless of depth changes. Consequently, buoyancy control with Avelo feels ultra-stable and at the same time effortless when diving Avelo compared to when diving with a BCD.

9. Does the Avelo team have a problem with BCDs?

Not at all. We are all professional BCD users and instructors. BCDs became an important part of scuba for very good reasons. They allowed a much wider sector of the population to participate in this amazing activity. This led to widespread awareness of how fragile the underwater environment is.

The growth in scuba diving provided an important economic engine to displace harmful marine practices in many areas of the world. BCDs should receive a lot of credit for their part in this.

We have now found a much better way to manage buoyancy and believe Avelo will lead to an even wider expansion of the diving community.

10. Why don’t you have all the answers to every potential scenario in these FAQs?

Our experimental dive team includes professional and experienced scuba divers developing safety protocols and guidelines. The design of the system and the certification program stems from years of development according to these guidelines. Participate in our certification programs to learn how to dive Avelo. Although some basic concepts can be explained on the website, many concepts are interconnected and need to be experienced systematically. Our RAD and Avelo Pro courses are designed to do that in a way that will upgrade your diving experience from the very first minute of your Avelo dive.

11. My neutral buoyancy is already fantastic. I am an instructor/instructor trainer/technical diver/dive professional with thousands of dives. What does the Avelo System offer me?

During our pilot program, we trained many dive professionals with thousands of dives as well as multiple industry veterans who held (or currently hold) key positions in the scuba industry. One by one they came out of the water telling us we completely changed what they knew about neutral buoyancy. We are all very experienced dive instructors, and we all taught “perfect buoyancy” using standard scuba hundreds of times. Once you dive Avelo, what you perceive today as “perfect buoyancy” will look like a feeble attempt at remaining in one spot in the water column. At best. This has far-reaching consequences on your workload (both mental and physical), your air consumption rate (great as you may think it is), and your safety. You don’t have to take our word for it. See what Dan Orr has to say about it: https://youtu.be/ECw53h0eGFI

12. How do I maintain the Avelo System?

Avelo Dive Center s are equipped with Avelo Technicians who can maintain and repair the Avelo System. Visit your local Avelo Dive Center for your maintenance needs.

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