Scuba divers are obnoxious. To ­marine life, we are noisy and intolerable. It’s no wonder aquatic creatures able to move typically bolt from our presence as quickly as possible. Or, even worse, they don’t venture near at all. The offensive byproducts of open-circuit scuba are a necessary evil for most of us, but not ­rebreather divers.

A closed-circuit rebreather (CCR) ­employs advanced technology to ­recycle breathing gas in a closed-loop system that makes the underwater experience virtually bubble-free. Beyond this near-silent bliss, ­rebreathers ­offer ­further benefits, including ­increased bottom time, decreased ­decompression obligations and ­fewer physical discomforts such as dry mouth, core-temperature ­reduction and fatigue. In short, a rebreather can improve the way divers experience the underwater world in profound ways.

“The rebreather allows me to do dives that logistically wouldn’t be possible, or would be incredibly complex to plan safely using open circuit,” says Gemma Smith, a British master scuba diver trainer and CCR instructor. “One of the best dives I’ve ever done was in Finland’s flooded Ojamo Mine at a place called Lucifer’s ­Pillar at almost 70 meters (230 feet). We spent an hour there filming, and I remember looking around and seeing the whole structure illuminated, hearing nothing but silence, and thinking that we were truly on a different planet. It wouldn’t have been as magical if we had the time constraints, noise and reduced ­visibility due to percolation that diving on open ­circuit would have created.”

“As a cardiologist, I was intrigued by the physics and physiology of ­rebreathers, and then fell in love with the silent nature, warm and moist breathing gas, and prolonged no-decompression times,” says Florida rebreather ­instructor Doug ­Ebersole. “While I’m a tec diver who enjoys caves and deep walls and deep wrecks, I’m a warm-water, pretty-fish diver at heart. Although rebreathers are frequently thought of as best used in technical diving, I feel they have greatly enhanced my recreational diving as well.”

“CCR started off as something to keep me interested in recreational ­diving, considering that I am a busy ­instructor,” says Steve ­Tippetts, a rebreather ­instructor trainer in Grand Cayman. “The interest became a passion that turned into an ­obsession. The experience will really amplify your time ­underwater, enabling you to see things o­rdinarily missed, and develop your personal skills.”

All these advantages come at a price, however, including accepting added ­responsibility for risk, mastering complicated equipment, learning advanced techniques, and investing in expensive gear. But ask any rebreather diver — ­especially the experts tapped here — and they’ll tell you it’s totally worth it.

Forget what you think you know

For most recreational divers who use open-circuit scuba gear, ­rebreather ­divers look like an alien breed. With ­double hoses, multiple cylinders and bulky backpacks, these rigs can seem downright scary. But that’s only ­partially accurate.

“A lot of open-circuit divers can feel ­intimidated by rebreathers,” Smith says. “I have heard so many people say, ‘You must be brave to dive a machine that is trying to kill you,’ but the exact opposite is true. A properly maintained rebreather is actually trying to keep you alive. If you look at accident reports from divers on CCR, a large percentage of issues occur because of improper assembly or lack of safety checks — in other words, human error, not lack of machine ­functionality.”

“The most common misconceptions are that rebreathers are too complicated and time consuming to maintain,” says Ebersole. “Maintenance is actually very easy. And, while CCRs have potential risks beyond that of recreational open-circuit diving, these should be largely mitigated by checklists, good training and diligent monitoring of gauges.”

“Rebreathers don’t kill people. People kill people,” Tippetts says. “It takes time to become acquainted with the requirements of safe CCR diving, but once you do, life becomes simple.”

Get close to marine life

For most of us, the attraction of ­diving is rooted in marine-life encounters. ­Silent running with a CCR can make the ­seemingly impossible a reality.

“Watching a school of hammerheads swim close by, or being assimilated into a large school of fish, is an amazing ­experience,” says Ebersole. “The silent nature of rebreathers allows for better interactions with certain marine life.”

“Rebreathers afford huge advantages to underwater photographers. Whereas before marine animals would be scared off by the noise from open-circuit gear, now they swim around you completely unperturbed,” Smith says. “I know from my own experience taking photos underwater that certain shots were made markedly easier by diving a rebreather.”

Dive longer and more comfortably

Because a rebreather is ­constantly ­optimizing the mix of gases a diver is breathing, the system greatly expands that diver’s capacity to endure the ­physiological stresses of submersion.

“Diving a CCR is basically like having your own custom gas-blending device on your back,” Smith says. “The machine is always giving you the optimal gas mix for the depth you are at, and you are using a tiny proportion of the gas you would if diving open circuit because only the oxygen you metabolize is ­being replaced.”

“By diving the optimum gas mix, the diver has the lowest possible loading of inert gas, which means a ­recreational CCR diver can spend a couple of hours on a 60-foot reef without ever going into ­decompression,” Ebersole says. “­Additionally, the warm, moist gas of a rebreather avoids the dehydration, symptoms of cotton mouth and heat loss that divers often get from ­breathing cold, dry gas from an ­open-circuit ­cylinder.”

“The benefits of diving a CCR are too many to list,” Tippetts says. “For deeper, more-technical divers, it is the ­economy of gases, combined with more options to deal with problems ­underwater in a planned manner.”

Consider your needs and ambitions

For those contemplating crossing over to rebreather, tough questions about why, how and how often the apparatus will be used should be asked — and your ­answers considered carefully.

“In my opinion, every active diver should at least consider rebreather diving as long as their personality fits the CCR mindset.”

“CCR diving isn’t for everyone because there is so much more to consider when you dive closed circuit,” Smith says. “It’s a much bigger commitment both in time and knowledge — if you don’t require a ­rebreather to do the dives you want to do, then you shouldn’t get one.”

“For those who dive only on vacation once or twice per year, the additional training, expense and risk compared with open-circuit recreational diving is probably not justified,” Ebersole says. “In my opinion, every active diver should at least consider rebreather diving as long as their personality fits the CCR mindset. If a diver just wants to throw a tank on their back, jump in the water, and then just dunk everything once ­until the next time, CCR diving is probably not for them.”

Take the next step

If you’re primed, prepared and pumped, it’s time to start shopping for the right unit and the right instructor.

“Ask lots of questions to determine what you want from the rebreather,” ­Tippetts says. “It is a tool to achieve an objective, so not all CCRs are the right fit for all applications. Try them out in a pool; some might ‘feel’ better than others. And be careful of opinions. Find out about the support from manufacturers and what the infrastructure is around where you’re going to dive.”

“Most agencies have a minimum age and require tec-­diving experience before moving on to rebreather,” Smith says. “Once you meet the prerequisites, the biggest l­earning curve is understanding the machine. Most divers have no issues in the water, but learning maintenance, gas-flow dynamics, and how the machine is actually working takes longer.”

“Training takes about five days and includes several hours of academics — physics, physiology, CCR design, assembly and breakdown, trouble shooting, maintenance, etc. — and eight hours of (confined and open water) in-water time with the instructor working on ­buoyancy, trim, bailout scenarios, and ­emergency ­procedures, as well as simply getting comfortable on the unit,” says Ebersole. “In my experience, the first day or two can be frustrating, especially to very experienced open-circuit divers, because it is like starting over again with diving in terms of trim, buoyancy and task loading. However, by days four and five, they can become very comfortable with CCR ­diving.”