The best Rebreathers in 2024

Looking for the best rebreathers in 2024 to dive for hours on end?

Rebreather diving is becoming more popular and accessible every year. Yet, very few people actually try it out.

In this guide, we’ll tell you everything you need to know about rebreathers, how they work, and how to get started.

You’ll also show you some of the best models to try out this year.

What is rebreather diving?

In rebreather diving, we use a rebreather apparatus instead of a traditional open-circuit scuba system to breathe underwater. Unlike in scuba where exhaled gas is released into the water, rebreathers recycle part or all of the exhaled gas and feed it back. This means divers can stay underwater much longer and reach greater depths without risking gas poisoning.

This recycling process in a rebreather involves removing carbon dioxide from exhaled air and adding oxygen as needed.

This allows for longer divers, less risk of oxygen poisoning and decompression sickness, as well as other benefits.

There are two different types of rebreather diving: Closed Circuit and Semi-Closed Circuit.

Rebreather diving is very different from the much more common “scuba” approach. And MUCH more expensive to get started.

It has become an innovative solution for those seeking to push the boundaries of traditional diving, exploring deeper depths, and engaging with marine life without disturbing their environment.

How Does a Rebreather Work?

At the heart of the rebreather system are three primary components:

• Scrubber: Removes carbon dioxide from the exhaled gas.
• Oxygen Cylinder: Supplies oxygen to maintain the appropriate breathing mix.
• Counterlung: Acts as a “breathing bag”, storing gas during the exhale and providing it during inhalation.

The system works by adjusting the proportion of oxygen in the breathing gas according to the diver’s depth and oxygen consumption, optimizing gas usage and allowing for extended underwater time.

Let’s look at this in a bit more detail:

Firstly, the Scrubber removes carbon dioxide from the exhaled gas, ensuring that you’re not breathing harmful levels of CO₂.

Secondly, the Oxygen Cylinder supplies oxygen to maintain the appropriate breathing mix. Modern systems allow for even further gas mixtures such as Trimix for deep diving.

Lastly, the Counterlung acts as a “breathing bag”, storing gas during the exhale and providing it during inhalation. No gas bubbles are released, making rebreather diving much more quiet and arguably more efficient than traditional scuba systems.

With these components working seamlessly together, rebreathers adjust the proportion of oxygen in the breathing gas according to the diver’s depth and oxygen consumption. This optimization results in more efficient gas usage and provides divers with a more customizable diving experience.

Rebreather vs. Open Circuit

The traditional open circuit diving involves breathing in from a tank and exhaling gas into the water in the form of bubbles. In contrast, rebreathers reuse most or all of the gas you exhale. While open circuit systems are simpler and more commonly used, rebreathers offer longer dive times, less noise (bubble-free), and often warmer and moister breathed gas. However, rebreathers can be more complex and require more diligent maintenance.

SCR vs CCR

While both are rebreathers, Semi-Closed Rebreathers (SCR) and Closed-Circuit Rebreathers (CCR) operate differently. SCRs release a small portion of the exhaled gas into the water, while CCRs retain all exhaled gas within the system. SCRs are simpler and often cheaper but are less efficient in gas conservation than CCRs. CCRs, being fully closed systems, offer optimal gas efficiency and precise control over breathing mixtures.

While both are rebreather systems, CCR models are usually more expensive.

1. Gas Recycling Mechanism:

• SCR (Semi-Closed Circuit Rebreather):
  • Only a portion of the exhaled gas is recycled back to the diver. The rest is vented into the water.
  • Typically uses a constant flow of mixed gas (such as Nitrox) into the breathing loop, with excess gas being vented off.
• CCR (Closed Circuit Rebreather):
  • Almost all of the exhaled gas is recycled and reused.
  • Removes carbon dioxide and replaces the oxygen that was consumed by the diver, ensuring a consistent and optimized breathing mixture.

2. Gas Efficiency:

• SCR:
  • Less efficient than CCR because it continually vents a portion of the breathing gas into the water.
• CCR:
  • More gas efficient as it only replaces the oxygen that the diver consumes.

3. Gas Mixture:

• SCR:
  • Generally uses a pre-mixed gas supply, such as Nitrox.
  • The partial pressure of oxygen (PPO2) can vary during the dive, which can limit depth and duration.
• CCR:
  • Often has separate oxygen and diluent (a diluting gas like air or trimix) cylinders.
  • Allows for real-time control over the PPO2, providing an optimal mix at varying depths.

4. Complexity and Cost:

• SCR:
  • Generally simpler in design and operation compared to CCR.
  • Usually more affordable than CCR systems.
• CCR:
  • More complex due to the need for accurate oxygen sensors, solenoid valves, and electronic control systems.
  • Typically more expensive, both in initial cost and maintenance.

5. Duration and Depth:

• SCR:
  • Suitable for recreational dives, but might not be ideal for very deep or long dives due to varying PPO2.
• CCR:
  • Allows for longer dive durations and deeper dives due to the precise control over gas mixtures.

6. Safety Considerations:

• SCR:
  • Fewer potential failure points than CCR. However, the diver needs to monitor depth and time limits more closely due to fluctuating PPO2.
• CCR:
  • Requires meticulous pre-dive checks, especially regarding oxygen sensors and electronics. Although it offers precise control over the breathing mix, malfunctioning equipment can pose serious risks if not properly managed.

In summary, while SCR offers a simpler and often more affordable entry into rebreather diving, CCR provides a higher degree of precision, control, and efficiency, especially favored by technical divers aiming for deeper or extended dives. The choice between the two often depends on the diver’s needs, experience, and budget.

Advantages of Rebreather Diving

Rebreathers allow for much longer dive times, completely silent diving, extended non-decompression limits, and less breathing effort. They make deep diving and explorations of unknown areas much simpler and more accessible and are great for marine researchers.

Longer dive times and extended non-decompression limits are probably the reason most divers wish to pick up a rebreather eventually. This is made possible by the automatic gas management built into modern rebreathers that optimize gas mixture and management.

Additionally, rebreather diving is essentially silent diving since no bubbles are emitted from the regulator. This makes it a favorite for underwater photographers and wildlife enthusiasts hoping to approach marine life without causing disturbances.

Really, the difference is like night and day.

If you ever dive with a rebreather diver as a scuba diver, the first thing they’ll you after how “loud” you were. 😄

The Warm Moist Breathing Gas produced by the rebreathing process also makes the breathing process a lot more comfortable.

Here are even more advantages:

• Longer Dive Times: With efficient gas usage, divers can remain underwater longer.
• Silent Diving: Rebreathers produce no bubbles, ensuring a quiet dive experience and making it a favorite for underwater photographers and wildlife enthusiasts.
• Warm Moist Breathing Gas: The rebreathing process warms and moistens the gas, making it more comfortable for the diver.
• Extended No-Decompression Limits: Potential for longer bottom times without the need for decompression stops.
• Optimal Gas Mix: Rebreathers can provide an ideal breathing gas mixture at varying depths, increasing safety and dive efficiency.
• Extended No-Decompression Limits: Rebreathers can allow for longer bottom times at depth without requiring extended decompression stops.
• Decreased Gas Weight: For longer dives, rebreathers often require carrying less weight in gas compared to open-circuit systems, making them more streamlined and reducing drag.

Rebreather Diving Courses

Like other advanced diving activities, rebreather diving requires specialized training and certification. Certifications are typically categorized by the type of rebreather (e.g., semi-closed or closed-circuit) and by depth limits. Major training organizations like PADI, TDI, and IANTD offer rebreather courses.

Each course emphasizes equipment handling, safety procedures, and dive planning tailored to rebreather diving. Additionally, it helps to have a solid understanding of technical diving, especially decompression procedures, deep diving, and gas management.

Safety Considerations

Rebreather diving, like all forms of diving, requires a commitment to safety. Mastery of the equipment is only the first step.

Divers must ensure they’re trained and certified for their specific rebreather and that they regularly service their equipment. Equipment Familiarity cannot be emphasized enough.

Divers should also adhere to the Buddy System, ensuring they dive with someone familiar with rebreathers, ensuring mutual safety. With the added complexity of rebreather systems, divers need to continuously monitor gas mixtures and depths using their dive computers.

Planning Your Dive is crucial; a good plan considers depth, bottom time, gas management, and potential hazards.

As usual, staying hydrated and fit is a significant factor in reducing risks like decompression sickness.

• Equipment Familiarity: Know your equipment inside and out. Regularly maintain and check your rebreather.
• Training: Only dive within the limits of your certification and training.
• Buddy System: Always dive with a buddy familiar with rebreathers.
• Regular Monitoring: Continuously monitor gas mixtures and depths.
• Plan Your Dive: Plan the dive and dive the plan. Consider factors like depth, bottom time, and gas management.
• Pre-dive Check: Test your rebreather before every dive.
• Hydration and Health: Being well-hydrated and in good health can reduce the risks of decompression sickness.

Rebreather Diving Equipment

A rebreather requires a totally different setup from regular scuba gear.

Here are the essential parts of the rebreather diving equipment:

Rebreather Unit: The core apparatus and backbone of the system that contains the scrubber, gas cylinders, and the counterlung.

Dive Computer: Monitors oxygen levels and provides essential diving data. The rebreather dive computer is often attached to the rest of the unit and specific to it.

Of course, it’s still possible to use a separate wrist-mounted dive computer, however, each rebreather usually comes with its own.

Bailout Cylinder: A backup open-circuit system, in case the rebreather fails. The Bailout Cylinder, while hoping never to use it, is a vital piece of safety equipment; it serves as a backup open-circuit system in case the rebreather malfunctions and often works like a regular scuba regulator.

Lastly, the Mouthpiece is where the diver breathes from, connected directly to the rebreather unit.

Military Rebreather Diving

Rebreathers hold significant value in military operations. The absence of bubbles and silent operation make them ideal for covert missions, underwater demolitions, or reconnaissance. Military-grade rebreathers are often rugged, have advanced features, and are tailored to the specific requirements of defense operations.

Frequently Asked Questions

Q: How long can you stay underwater with a rebreather?

A: Depending on the unit, gas supply, and depth, divers can remain submerged for up to 12 hours! However, other factors like water temperature, physical exertion, and specific dive objectives can influence dive times.

Q: How deep can you dive with a rebreather?

A: With a rebreather, divers can potentially reach depths greater than traditional recreational limits. Some technical rebreathers enable dives beyond 100 m / 330 ft. However, such depths demand specialist training, experience, and detailed planning due to increased risks and required decompression stops.

Q: Are rebreathers dangerous?

A: While there are risks associated with rebreathers, with proper training, maintenance, and a commitment to safety, they are safe to use!

Q: Why are rebreathers so expensive?

A: The complexity of rebreathers is a primary factor in their cost. Precision components ensure the system’s reliability and safety. Also, significant research and development investments go into creating and refining rebreather technology, which adds to the cost.

Conclusion

In conclusion, rebreather diving offers a unique and extended underwater experience, but it also requires a commitment to safety, training, and regular equipment maintenance. Before embarking on this advanced diving journey, ensure you’re prepared and informed.