The Shift to Rebreathers: Why Divers Are Switching to CCRs
James McMullin Aug 06, 2025
The Shift to Rebreathers: Why Divers Are Switching to CCRs
By James McMullin, Instructor Trainer and Owner/Operator of Signature Scuba Diving
As the world of underwater exploration continues to evolve, divers are increasingly transitioning from traditional open-circuit systems to closed-circuit rebreathers (CCRs). One of the most popular and trusted models in this shift is the Hollis PRISM 2—valued for its reliability, modularity, and user-friendly design.
At Signature Scuba in Rancho Cucamonga, we’ve seen this evolution firsthand. In this article, I’ll break down how rebreathers work, why they’re growing in popularity, and what makes the PRISM 2 a standout option for both technical and recreational divers.
What Is a Rebreather?
A rebreather allows divers to recycle their breathing gas rather than release it into the water like a traditional open-circuit system. This closed-loop system is highly efficient: it scrubs out carbon dioxide (CO₂), replenishes oxygen, and enables significantly longer dives with less gas consumption.
How the PRISM 2 Rebreather Works
1. Closed-Loop System:
Divers breathe through a mouthpiece connected to counterlungs. As oxygen is metabolized, carbon dioxide builds up in the system.
2. CO₂ Scrubbing:
A chemical scrubber removes carbon dioxide from the loop. This is critical—excess CO₂ can lead to hypercapnia, which is extremely dangerous underwater.
3. Oxygen Injection:
The system automatically injects oxygen or a gas mix to replace what has been used. The PRISM 2 excels in maintaining safe PPO₂ levels during the dive.
4. Real-Time Monitoring:
Advanced electronics continuously track oxygen levels and alert the diver if there’s an issue, increasing both safety and confidence during dives.
Why Are Divers Switching to CCRs Like the PRISM 2?
1. Extended Bottom Time:
Because gas is recycled, divers can stay underwater significantly longer without changing tanks—ideal for deep, technical, or photo-intensive dives.
2. Reduced Gas Consumption:
CCRs use far less gas than open-circuit systems. This reduces overall weight, cost, and logistical requirements—especially on remote dive trips.
3. Minimal Bubble Output:
Closed-circuit diving creates very few bubbles, offering a stealthier approach for marine photographers or divers exploring sensitive habitats.
4. Better Buoyancy and Comfort:
The PRISM 2’s back-mounted counterlungs (BMCL) provide streamlined movement and easier buoyancy control, improving diver comfort and efficiency.
5. Enhanced Safety:
With reliable electronics, multiple sensors, and a proven track record, the PRISM 2 is engineered for deep and demanding dive environments.
The Hollis PRISM 2 at a Glance
User-Friendly:
Ideal for new CCR divers and experienced tech divers alike. The layout is intuitive, simplifying operation and maintenance.
Highly Customizable:
The PRISM 2 is modular and can be configured for caves, wrecks, deep trimix dives, and more. Adapt your setup to match any dive mission.
Rugged and Reliable:
Engineered with durable components, the PRISM 2 handles harsh conditions with confidence.
CCR Training: Preparation Is Everything
Switching to a rebreather system is not plug-and-play. It requires comprehensive training that includes theoretical knowledge, practical skills, emergency procedures, and situational awareness.
At Signature Scuba, our CCR programs focus on:
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Gas Management and Physiology: Understanding PPO₂, gas laws, and how the body responds to rebreather systems.
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Hands-On Skills: Every dive is a training dive. We cover assembly, maintenance, and real-world emergency simulations using the PRISM 2.
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Confidence Through Practice: We believe cockiness kills, but confidence saves lives. Through real dive environments, we help divers build comfort and mastery with their equipment.
Additional Benefits of Rebreathers
Environmental Impact:
By recycling gas and reducing emissions, CCRs are a more sustainable choice, especially in sensitive marine ecosystems.
Less Noise and Disturbance:
Silent operation enhances the diver's connection with nature—and increases chances for marine life encounters.
Photographer's Dream:
Longer dives, fewer interruptions, and no distracting bubbles make rebreathers the preferred choice for underwater photographers.
Versatile Dive Applications:
From recreational ocean dives to cave and wreck penetrations, the PRISM 2 handles it all.
Considerations for New CCR Divers
Training Requirements:
This isn't a casual switch. Proper CCR training is essential for safety and effectiveness. You'll learn bailout procedures, sensor calibration, PPO₂ control, and more.
Maintenance:
Rebreathers require regular, disciplined maintenance. You'll need to check scrubbers, oxygen cells, and backup systems before every dive.
Complexity and Awareness:
CCR diving demands more attention to detail. Gas monitoring and emergency protocols must become second nature.
Emergency Preparedness:
All CCR divers must be skilled in bailing out to open-circuit systems. A great rebreather diver is first a great open-circuit diver.
The Role of Community and Support
Making the leap to CCR diving can feel overwhelming—but you’re not alone. At Signature Scuba Rancho Cucamonga, we offer not just CCR training but a supportive community of instructors, tech divers, and dive buddies to help guide your journey.
We encourage participation in dive clubs, specialty events, and ongoing workshops so you can keep your skills sharp and your confidence high.
Conclusion: Embrace the Future of Diving
The shift to closed-circuit rebreathers, especially systems like the Hollis PRISM 2, represents a leap forward in scuba diving technology. With extended dive times, quieter profiles, and more immersive experiences, CCRs open up a whole new world of underwater possibility.
At Signature Scuba, we are proud to offer certified CCR training, expert guidance, and the resources you need to dive safer and deeper. Ready to make the switch? Let’s take your diving to the next level.
Visit us in Rancho Cucamonga or call 909-476-8183 to begin your CCR journey today.
