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Longer bottom time at depth meant that after all the other divers in the group had to surface, I was able to spend more time with this massive giant Pacific octopus, just she and I, as she hunted across the bottom
 

The old joke goes: “When you get tired of spending money on scuba gear, take up underwater photography.” Today we can add: “When you stop feeling the pain of buying all that underwater photography gear, start diving with a closed circuit rebreather!”

All jokes aside, diving with a rebreather can be incredibly fun and rewarding. I bought my first rebreather in 2007 after many years and over 500 dives on open circuit (aka traditional scuba gear). I participated in dive clubs which had several people using CCRs. For years, I closely observed them and was not interested due to the frequent hassles and technical issues they experienced. What changed for me in 2007 was the arrival of some new and improved CCRs combined with my growing passion for underwater photography. Learning to dive a rebreather was also an opportunity to learn some fascinating new skills and better understand diving physiology. I hoped it would further enhance my underwater photography experience.
 

Cloud and glass sponges generally grow deep. Having the chance to photograph one properly isn’t a frequent privilege, so having a rebreather and really being able to dial in and create an image was made possible by using a rebreather and the much greater no-decompression limits they provide
 

To be sure, I learned a lot of new skills and became a better diver. CCR training includes a more detailed understanding of the physics and biology of diving—concepts like partial pressures of breathing gases, the physiological responses to oxygen, carbon dioxide, and nitrogen under pressure, and how these gases can keep you alive or cause injury or death. I started to learn a lot more about the scuba gear I had been casually using for years, picking up a better understanding of how equipment like regulators function as well as how they can fail. Perhaps the biggest and most important part of the training was how to be a safer diver, with endless drills on how to recognize, react, and resolve any equipment failures that might occur during a dive.

Sadly, my CCR training did not cover anything about integrating underwater photography into my diving. I had to learn all of that on my own. In this article, I hope to pass some of that along to you.
 

Unlike many animals that are spooked by divers’ bubbles, mantas—especially those found around Socorro, Mexico—actually seem to seek out bubbles and enjoy the feeling on their bellies. Not the best case for a rebreather!

What Is a Closed Circuit Rebreather?

In the simplest terms, a rebreather is a scuba diving unit that recycles the diver’s breathing gas, adding oxygen (O₂), and removing carbon dioxide (CO₂) to maintain an optimal gas mix. An open circuit diver inhales gas containing 21% oxygen (or a higher nitrox mix) and exhales ~15% oxygen along with 6% CO₂. In other words, three-quarters of the oxygen content of the breathing gas is wasted and exhaled into the water along with a lot of nitrogen. A CCR unit employs a closed circuit breathing loop that moves exhaled gas through a granular scrubber without losing any gas. The scrubber removes excess CO₂ and the unit injects additional oxygen as required. In this way, the device makes full use of all breathing gases.
 

The author’s fully kitted out KISS rebreather
 

The result is a scuba device that uses far less tank gas and provides an optimized gas mix that minimizes nitrogen uptake by dynamically maximizing the fraction of oxygen in the mix appropriate for a given depth continuously throughout the dive. This is accomplished by monitoring the partial pressure of O₂ (PPO₂) with oxygen sensors. This efficient process enables significantly longer dives with greatly reduced no-decompression limits (NDL). In addition, your dives are not usually impacted by how much gas you carry. In fact, a CCR diver will use about the same amount of gas at 80 feet versus 20 feet. On open circuit a diver would use double the gas at 80 feet. The tradeoff is the CCR must perform the additional task of scrubbing out CO₂ from the breathing loop and monitor/maintain the oxygen content of the gases.
 

A diver with a rebreather gets an up-close and personal look at a fantastic pair of wolf eels on a deep reef in the Pacific Northwest. The lack of bubbles often allows for a much closer and more intimate approach to marine life

Benefits of CCR for Underwater Photography

No Bubbles

One of the biggest benefits of not generating bubbles is that marine life will generally be much more comfortable around you. This is particularly noticeable with sharks and doubly so with hammerhead sharks. Hammerheads are notoriously skittish of bubble noise, and it’s rare for open circuit scuba divers to get close to individuals or a big school. My first diving experience in Socorro with a group of CCR divers was amazing. We frequently saw the schools of hammerheads and they would not scatter in our path. Amazing! Conversely, the giant oceanic mantas of Socorro love to have bubbles on their bellies—and you can supply these from your bailout bottle.

Keep in mind that many fish are also scared of movement, bright lights, shadows you cast, and more. There are a few chill fish that are more likely to swim toward a CCR diver, resulting in fewer fish-butt shots to discard. Shooting straight up can also benefit, as your own bubbles won’t spoil your shot. In many cases, the lack of bubbles will be a minor benefit to photography at best. Still, you’ll never tire of the silent, peaceful experience on CCR.
 

Not typically the boldest of fish, and a species that will often back into a hole upon approach, this mosshead warbonnet seemed less perturbed by my presence in the absence of any bubble noise

Time on Target

Perhaps the greatest underwater photography benefit of CCR diving is the additional time you can spend with a subject. Since you are no longer constrained by your gas supply, and you have greatly increased NDL, you may not have to leave a “premium subject” as soon. I have had this experience many times and have come to value it. I can share a few examples.

I was diving in the Hood Canal in Washington State with a group of other divers. At about 80 feet, we encountered a giant Pacific octopus out in the open. It was very active, moving across the sloop and maintained a brilliant red coloration. I managed a few shots with other divers, but there was quite a crowd. I backed off and followed along for about 15 minutes. At that point, the other divers were running low on NDL and/or gas supply and had to turn. I ended up spending another 30 minutes with this magnificent octopus by myself.

Earlier this year, I was diving with God’s Pocket Resort in the Browning Pass at the north end of Vancouver Island, British Columbia. One of the marque dive sites is Browning Wall, famous for the extensive coverage of colorful soft corals, sponges, and critters on a deep vertical wall. Near the beginning of the dive, I spotted another giant Pacific octopus on the most colorful part of the wall down at 80 feet. I took a few photos of it and showed it to my dive buddy. I then backed off and let other divers have a chance to photograph this amazing creature. I kept back and watched, but before long the open circuit divers had to ascend to shallower depths due to NDL. I moved back into position and captured the octopus from multiple angles and got one of my favorite photos of the trip.
 

Another giant Pacific octopus, found at around 80 feet, that I was able to spend extra time with after the open circuit divers had to head to shallower waters due to NDL
 

A final example involves the summertime arrival of sixgill sharks in Puget Sound. Each August brings a visitation by young sixgills in to the “shallow waters” off the beaches near Seattle. These sharks spend most of their lives well below 3,000-feet-deep, dark, and cold water. Sixgill sharks grow to be over 15 feet long, but the young 6–10-foot sharks like to visit the shallows of Redondo Beach Park and cruise by at 80–90 feet of depth. Sightings are rare, so the more time you spend at depth, the better your chances are to see one.

I’ve spent many dives just orbiting around 90 feet over the sand and silt waiting for a shark. It’s a shock and thrill when you finally see one. Diving on the rebreather, I can easily spend 45 minutes at 90 feet, waiting for a shark without ever running out of NDL and going into deco. And if I do dip below my NDL, by the time I am back up to 20 feet, the decompression obligation has already burned off by the high oxygen/low nitrogen mixture I was breathing as I approached the shallows.
 

Sixgill sharks make it into scuba depths during summer months, but they often are still deep enough that without a rebreather, divers are limited to just a few minutes with the sharks

Rock Steady Buoyancy

When you first begin to learn on CCR, most divers feel like they must start all over with buoyancy control. The closed circuit of the breathing loop includes a counter lung. The counter lung is an airtight bag of tough fabric that expands and contracts as you exhale and inhale. As a result, you don’t lose any gas, and your buoyancy does not change as you breathe. As we all know from open circuit scuba, you will rise and fall with each breath as you fill your lungs with tank gas and then exhale it into the water. Holding your breath is not a good idea.

Once CCR divers get their trim just right and master their buoyancy, they become a remarkably steady platform. When CCR buoyancy is just right, it feels like you are a train on railroad tracks. You move forward super smoothly with zero vertical movement. You hold vertical position without moving your fins, hands, or using a muck stick as an anchor. You can easily float inches over the sand as you shoot macro at a muck site or on the edge of a reef around delicate corals. You become a steady platform capable of shooting the tiniest subjects. I find this makes photography much easier, and with less risk of disturbing delicate marine environments.
 

Stellar’s sea lions turning a diver and her rebreather into a chew toy!
 

To see more of Dave’s underwater work, please give him a follow on Instagram and check out his newsletter on the Marker Buoy Dive Club website.