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Whole Lotta CHO2ptima Going On

Launched in early 2020, just as the pandemic was getting started, Dive Rite’s innovative chest-mounted O2Ptima, aka the CHO2ptima, is generating significant buzz among instructors and users as the hot new rebreather on the market. Accordingly, InDEPTH chief Michael Menduno sat down with general manager Jared Hires to explore Dive Rite’s latest purpose-built creation. Is there a CHO2ptima in your future (carry-on case)?

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By Michael Menduno. Header image: Max Kuznetsov going through the Manhole at Ginnie Springs by Fan Ping. Other images courtesy of Dive Rite unless noted. Full disclosure: Dive Rite is a sponsor of InDEPTH.

🎶🎶 Pre-dive Clicklist: A Whole Lotta Shakin’ Going On by Jerry Lee Lewis

Various brands of mixed gas rebreathers have taken their turn in the spotlight over the years as a result of their functionality and innovation. In the early days of the 21st century, it was AP Diving’s pioneering rebreather, the Inspiration, followed by the KISS Classic, and shortly after, Inner Space Corp’s Megalodon that were grabbing all the attention. Later, the rEVO and Hollis PRISM came to prominence. The O2ptima drew attention. Poseidon had its day in the sun when Type R i.e., recreational rebreathers were a thing. Remember them? Of course, in recent years, the JJ-CCR, including GUE’s configuration, the Fathom, and Divesoft’s Liberty—both backmount and sidemount versions—have garnered significant community attention, and still do. 

However today, it is arguably Dive Rite’s unique and innovative rebreather, the O2ptima Chest Mount, aka “The CHO2ptima,” which was launched during the early days of the COVID-19 Pandemic, that is receiving considerable buzz in the market and garnering new instructors and users. Ironically, while the community collectively moved to back-mounted counter lungs (CL) to free up chest space, Dive Rite has taken a different approach altogether, and moved its rebreather to the front of the diver, reminiscent of combat divers units (offering optimal CL placement when in trim), and that’s only part of its novelty. 

Weighing in at 7.7kg /17 lbs and able to fit in a small carry-on roller case, its compact size along with its ability to interface with practically any open circuit configuration—from Rec to Tec—to drive it, makes CHO2ptima a serious choice in travel rebreathers. As the tagline says, “Dive Rite—Equipment for Serious Divers.” Interestingly, many divers, including some GUE members, are considering the CHO2ptima as their next rebreather.

Accordingly, we reached out to Dive Rite’s 31-year-old General Manager Jared Hires, who has been diving rebreathers since he was 15, to take us for a deep dive into their newest rebreather. Hires, who is an active, advanced Technical Diving International (TDI) tech and CCR instructor, and an apprentice cave instructor with the National Speleological Society-Cave Diving Section (NSS-CDS), explains the philosophy behind the CHO2ptima and its development, discusses its use and applications, and talks about the possibility of getting the unit CE-tested, so it can be sold in Europe. 

I conducted the interview with Jared while he was in between duties managing the nearly 40-year old family business, and teaching a CHO2ptima class. Here is what the man had to say.


InDEPTH: Dive Rite launched its O2ptima backmount rebreather in 2006. Then, in March 2020, you launched the O2ptima CM, aka “The CHO2ptima”—a modified O2ptima with chest-mounted counterlungs. I get the distinct impression that the CHO2ptima has surpassed its predecessor’s sales by quite a bit, and there’s considerable buzz around the unit. Is that an accurate characterization?

Jared Hires: The CHO2ptima has gained a lot of attention since its release, and sales have surpassed the backmount version. I think this can be attributed to several different factors. Since the unit is integrated into a diver’s primary gear configuration, they are less apprehensive in making the jump to a CCR. There is less of a learning curve since everything is not new.

Another contributing factor is cost. The CHO2ptima is extremely affordable (by rebreather standards), which is making it more attainable for divers. I would like to think that we have grown the rebreather market, not that we have just taken a larger portion of the pie.

Jared Hires sporting his CHO2ptima

What’s the retail price?

$6,900 with a Shearwater Petrel 3 controller or $7,200 with a NERD 2 Controller.

Wow. That is very affordable. Lamar [Hires] told me that CHO2ptima sales really made a difference during the pandemic!

Releasing a new rebreather at the start of a pandemic was hard. It was difficult to get it out there for people to see and to get instructors up to speed. Somehow, we were able to do it. It was a welcomed addition to our line and helped the business continue to grow through the pandemic. We have been extremely busy.

So, how did the CHO2ptima come about? What was the motivation?

It was a long project—something that we were working on for at least three to four years. During that process, we tried out many different concepts and renditions. It all really stemmed from the fact that sidemount rebreathers had started to become popular, and we had people asking for them. People were wondering if we were going to offer one since we had already made a name for ourselves in sidemount. We were the first to offer a commercially-available sidemount rig and one of the pioneers in sidemount diving. It seemed natural that we also have a spot in the sidemount rebreather market.

I remember some of Lamar’s early sidemount units that he developed with Woody Jasper and Wes Skiles back in the day.

That’s right. Of course, we also had a very strong background in rebreathers working on producing the O2ptima since the mid-2000s and having lots of units on the market. So we started working on a concept. 

One of the things that held us back from sidemount rebreathers, especially early on, was the fact that all of the units at the time, like the SF2 or the KISS Sidekick, featured a single sidemount rebreather attached on one side, and most divers, particularly around here, wore a single bailout bottle attached on the other side. And a lot of people still do that. We didn’t really like that idea. 

We are cave divers, so it’s all about redundancy. You won’t see many of us going into a cave with only one bailout bottle. Some people in Florida were using a bailout bottle with an H-valve, so they at least had two regulators. That was a little bit better, but there were still quite a few people not carrying what we thought was adequate bailout. So that kind of turned us off on the idea of doing just a straight sidemount unit. 

Other integrated sidemount units, like the KISS Sidewinder, which has been really popular, alleviated the issue of bailout because the diver carried a bailout bottle on each side, which provided adequate bailout gas. The drawback was that it had to be completely integrated into your sidemount system. So, it wasn’t something that you could take off mid-dive if you were exploring and had to pass through a tight restriction. You essentially had to dedicate a complete sidemount rig to nothing but that. And we just didn’t like the concept of that either.

The idea was to modify Dive Rite’s O2ptima rebreather, right? 

That’s right. We wanted to keep as much of the O2ptima intact as possible—especially the scrubber design—we really liked the Micropore scrubber. It’s always easy to pack consistently. There’s no user interface when it comes to having to pack a scrubber. We also wanted to keep the electronics—we wanted a fully electronically controlled rebreather and not a manual rebreather. We didn’t want to have to sacrifice any of the features that we had come to enjoy on a traditional back-mounted O2ptima. So that’s why we started looking at the chestmount as an option rather than sidemount.

The chestmount would actually allow you to add it to any type of diving system. You could add it to any sidemount harness, you didn’t have to make modifications to an existing sidemount harness,and you didn’t have to worry about integrating it in and dedicating a rig to nothing but that. But it would also work with other configurations like back-mounted doubles or even a single tank.

Diver with backmount doubles and the ChO2ptima

So, the CHO2ptima started out as an exploration tool for sidemount—a sidemount rebreather concept, but it has now evolved to become a travel rebreather, basically, or an add-on rebreather to any open circuit configuration. People are diving them with a single tank, doubles, and sidemount.

I don’t know if all our readers know this, but a chest-mounted counterlung is optimal from a work of breathing perspective, assuming that you’re in trim. That’s why combat divers, who kick long distances, wear chest-mounted oxygen rebreathers.

That’s right. One of our design philosophies with the CHO2ptima, and actually the O2ptima as well, has been to keep the breathing loop as short as possible. Even on the backmount unit, the scrubber is right behind the diver’s head. As a result, our hoses and the counterlungs can be smaller since it’s got a shorter breathing loop. 

As you said, the lungs are right below your lungs, so also it’s not just the fact that the work of breathing is better, but even your change in buoyancy from breathing. That was one of the issues with sidemount rebreathers, the ones that go completely on your side. Every time you breathe, there is a slight shift in buoyancy and you will tilt to the side. Everyone will tell you that you just have to get used to it. But you can eliminate that by putting the lungs in the same exact position as your lungs as we did with the chestmount.

I know I felt relief went I went from over-the-shoulder counter lungs to back mounted counter lungs. How do your users feel about having the counter lungs over their chest? Does it feel cluttered or difficult to manuver?

I felt the same relief moving to backmounted lungs from the over the shoulder lungs on the O2ptima, and had some apprehension about the chest mounted ChO2ptima. The main relief felt with backmounted lungs is the ease of carrying bailout. You get the same relief with the chest mounted unit, especially if you’re using it with a backmount open circuit configuration. I can carry a lot more bailout comfortably with the ChO2ptima than I can with a BM unit. 

With the way the counter lung bag is shaped, most of the bulkier parts are lower down, so you really have the free use of your hands, and the chestmount does not get in the way on working dives. Even when diving in sidemount, I have easy access to my drysuit inflation and power inflator.

The rebreather is attached to the diver’s existing open circuit rig and is set up so that the diver can actually remove it during the dive; for example, in order to go through a restriction. That’s totally unique in itself.

For sure! That was one of the features and purposes that we envisioned for the unit. Generally, when we design equipment, we have a purpose for it. We don’t just set out to say, “Hey, we want to make a new gadget.” I like to think that sets our equipment apart from other dive gear manufacturers. We don’t just come up with a new color for something and release it as a new product. 

The CHO2ptima can be donned, removed and reddened underwater, and thus staged.

When we come up with something new, it has a purpose, whether it’s to make it easier to do a certain dive or alleviate a problem that divers have. 

Lamar definitely had in mind the ability to remove the unit underwater when we were designing the CHO2ptima. There are a couple of exploration dives that he had left off and wanted to go back to.

Yes, in the interview we did a few years ago, I remember Lamar talking about going back to Cow Springs. 

Yeah, his thought was, I want to be able to dive my rebreather all the way up to this tight restriction and basically remove and leave it, go through the restriction, do some exploration on open circuit going through these tight restrictions, come back out, grab my rebreather, and exit the cave. So, to do that, we wanted something that was completely independent. 

We also thought about travel. If divers are traveling and/or diving with friends, maybe they don’t want to dedicate a whole dive trip to a rebreather or dedicate all their dives to a longer dive or a bigger dive. We do this all the time when we go down to the Keys, for example. So, maybe in the morning we’re going to do a deep wreck dive with some decompression. I can carry a single 95 on my back with my CHO2ptima on the front, and stage a deco bottle. But then, in the afternoon, maybe I’m with my wife or with friends that are just diving a single tank dive on Molasses Reef, and I don’t want to have the complexity of a rebreather added into that dive. So, I just leave the rebreather on the boat and still have my same full configuration. We do that quite often.

So, it gives the diver maximum flexibility. That makes sense. I was at Bonaire Tek last Fall, and friends showed up with their CHO2ptima in a little roll-away travel case. It was impressive.

That’s right, when I travel, the whole rebreather, plus extras, fits in a carry-on Pelican case. And it was not just the rebreather. I had lights and all kinds of extra stuff in the carry-on case and the rest of my dive gear can go into its normal suitcase. That’s it. The unit itself only weighs 7.7kg /17 lbs.

When I travel with my backmount unit, it takes a large suitcase for the rebreather and another one for my camera and the rest of my dive gear. I barely have room for two swimsuits.

O2PTIMA CM

What I find most intriguing and unique is that the CHO2ptima can basically be worn with any sort of open circuit gear. 

Yeah, to add the CHO2ptima to any harness, to any configuration, all it takes is two attachment points on your shoulders and two attachment points on your waist. Some people are able to use the D-rings that they already have on their harness. However, I usually add an additional set that I dedicate just to the unit because I like the top attachment points to be up closer to my clavicle. And then I just add an extra set of D rings to my bottom. Two clips on your shoulder straps and two clips on your waist strap is all you need to add the unit. Then there’s a single low pressure inflator hose or whip to plug the unit into your back gas or to your side mount tanks or whatever. The only thing extra on your kit is a single additional inflator hose. 

The unit itself contains the scrubber, head, and oxygen cylinder.

That’s right. However, some people mount the O2 offboard, which you can do. You can carry your O2 as a stage cylinder, especially if you’re carrying a deco stage anyway, and you weren’t planning to drop it like some of the ocean guys do. So basically, everything else is selfcontained except for a diluent feed hose.

What were some of the challenges in packing all that functionality into a very small space?

It was a bit like trying to pack 10 pounds of shit in a 5 pound bag. That was definitely a challenge, but we were not willing to sacrifice any features.

The scrubber is in the middle, and then you have the head on one side, and the cap on the other side is basically a water trap—it’s the same exact module that we use on the back-mounted O2ptima. So that was the easy part. One of the biggest challenges was designing the outer bag, so it would accommodate most divers. Something that would fit a really tall guy wouldn’t fit someone who was petite. So we had to do some work on that. The counterlung design was also a big challenge. We went through multiple iterations trying to find just the right size that would provide good work of breathing but not add too much to the size of the unit.

The lungs are inside the unit?

Yes, the whole bag assembly contains your inhale and exhalation counter lungs in the bag. We had to do a lot of work on the designs of those counter lungs to make it all work. And there were little things along the way. We worked through several renditions of water trap designs, and we went through several Diver Surface Valve (DSV) designs and changed up some of the fittings to make them work just right. We looked at using an actual sidemount type DSV where the fittings came off of the DSV and went down. We ended up putting the elbows on the actual bag instead of putting them on the DSV to give it more of a natural feel. We also changed bag materials and added a pocket for accessories. 

What about for women divers? Do their breasts get in the way?

Luckily, wetsuits and drysuits take care of most of that for us. They actually act like a corset. So that hasn’t really been too much of an issue. The only people that maybe struggle are the guys with the big beer belly. We have a few of those in the community, but even for those guys, the CHO2ptima works pretty well. Big guys, like myself, don’t have a problem. However, the one group that has problems with a stock unit without making modifications are super short people. Because of the actual length of the unit, they may have issues. But that’s just with the standard mounting hardware. Many of these people can make a few adjustments to a stock CHO2ptima and have zero issues.

I see that you are also continuing with the Micropore scrubber cartridges, which are basically pre-packed scrubber cartridges that eliminate the need to hand pack the scrubber with sorb. I know that the military loves them. Are there other civilian rebreathers that use them?

I think we are currently the only vendor that is actively promoting the use of cartridges with their unit. When we first started using the Micropore cartridge in the early 2000s, there were some other ones. Most notably KISS had started using the cartridge—they actually made some units that were only able to work with the cartridge. Another was the Titan rebreather.

The French chest-mounted rebreather?

No, not the Triton but the Titan—the original one that was basically a backpack. It used Micropore cartridges. And we built the original O2ptima with the idea of using cartridges. At that time, 2003, 2004, the idea of cartridges was starting to pick up steam. So, there were a few units that used them, and divers were also making adapters for the AP Diving’s Inspiration, which was one of the first commercially available mixed-gas units on the market, as well as a few other rebreathers, so that they could use the Micropore cartridge. 

We bought into the concept, and still do—we think it’s the right way to do it. You remove the potential for user error in filling the scrubber, and it’s consistent and solid. That’s what’s written on the packaging, “A Solid Choice,” because you don’t have granules to deal with. Everything is exactly the same. People were using the extender cartridges because of the benefits. A lot of O2ptima users tell us that the cartridges are one of the reasons they like the unit. Of course, both the O2ptima and CHO2ptima unit can use granular sorb as well, so you are not locked into the Micropore cartridge.

You can do either one?

Exactly. Our scrubber was actually designed in collaboration with Micropore to give our unit the best work of breathing, the best duration and the best efficiency with the cartridge. So that was the main goal.

At the time, the mid-2000s, there was a big after market for conversions. A lot of divers were upgrading their units with Hammerhead Electronics, which was the gold standard of the day, and many were also having us add Dive Rite harnesses and buoyancy devices to their units, and as I mentioned, many were adding adapters to be able to use cartridges. 

Let me ask you about electronics. I know that you started with Hammerhead electronics on the O2ptima, but then eventually migrated to Shearwater electronics, which of course has become the de-facto standard in the tech market.

Yes, Hammerhead was a collaborator of ours. Our original units had Hammerhead electronics. We used them all the way up until about 2013. I believe it was the very beginning of 2013 when we made the switch to Shearwater. So, we had a long relationship with Hammerhead, and a great relationship with founder Kevin Jurgensen. He remains one of the pioneers in the rebreather world, and he’s a great guy. Unfortunately, there were others that came to market, and they were not able to keep up.

Shearwater was able to bring new technology to the market, both with their computers and rebreather controllers. They created a lot of buzz when they released the Predator in 2009 and they continue to do so.

I think JJ-CCR was the first rebreather manufacturer to go with Shearwater.

Yes, I believe JJ was first. Then others such as rEvo and Hollis started integrating them as well. After the Predator was released, we had many divers asking us to integrate them into the O2ptima. Some sent us in Fisher connectors to attach to their rebreathers so they could run a secondary Shearwater computer. A lot of our instructors and distributors were big Shearwater fans.

We finally met with Shearwater at the DEMA tradeshow in 2012. Later that year we got our first set of electronics, added them to the O2ptima and started doing test dives through the early part of 2013. I think we actually released the new unit at Beneath The Sea (BTS) 2013 using DiveCan and the Petrel controller.

I have a few more questions about electronics. Solid-state oxygen sensors? Is that something you are looking at, thinking about?

If they ever become readily available, yeah, we would look at them. And if Shearwater bought into the concept and integrated them into their technology, then we would, of course, look at it. We take the lead from them when it comes to sensor technology. Solid state sounds cool in theory. The thing is, you always have to have redundancy, so you’d need two of them at least. For sure, it would be awesome if you didn’t have to change out your sensors every 12 months.

How about scrubber thermal sticks and gaseous CO2 sensors. 

The sticks are not really CO2 sensors, but they do measure scrubber duration.

Right. They’re distinct from gaseous sensors. Only a few vendors are using either of these.

Thermal sticks are being used by a couple of manufacturers, most notably AP and rEVO. They track scrubber usage by looking at the temperature fluctuations caused by the chemical reaction of the scrubber. Thermal sticks tend to be an add on upgrade and not standard.

Some companies are also starting to use CO2 sensors as well, though they have not been widely adopted yet. The issue that we have seen with CO2 sensors is that they’re large. So, integrating one into a small package rebreather is hard. Another issue is that they don’t like moisture, and a rebreather is inherently a moist environment. The byproduct of the reaction in the scrubber is moisture— water and heat. They require extra precautions and consumables like desiccant packs to absorb the moisture. If those precautions are not strictly followed the sensors can produce false alarms. Eventually, if a diver gets too many false alarms, they become complacent and ignore the alarms altogether.

Right.

I know of many instructors who tell their students not to buy the CO2 sensor upgrades due to their finicky nature. Especially if diving in high humidity environments like the Caribbean.

But, when someone comes out with a sensor that is smaller and more reliable i.e., more humidity tolerant, then I think it would make a good additional alert. Remember that scrubber breakthrough is not completely linear. Breakthrough is exponential at the end of the scrubber life. When it breaks through, it’s an, “Oh Shit Moment,” and you need to bail out right away. 

Lamar Hires discussing the CHO2ptima
Assembling CHO2ptimas at Dive Rite in Lake City, FL. Photos by Fan Ping.

Let’s talk about building the unit. You build the CHO2ptima in the US right?

The ChO2ptima is assembled right here at our headquarters in Lake City, FL. We partner with other small companies here in the US for our machined parts and sewn pieces. But everything is brought into our factory in pieces to be assembled from scratch and to go through the rigorous final quality control check. 

The most tedious part is integrating the raw electronics that do come from Shearwater in Canada. From start to finish, a single rebreather head takes a minimum of 3 days to go through the different steps. This includes multiple components that are potted and over 300 solder points.

Made in America! That will no doubt appeal to some users. Talk to me about who is actually using the CHO2ptima.

The ChO2ptima is worldwide with divers across North America, South America, Asia, and Australia. This is one of the areas the pandemic hurt us with the launch, because instructors were not able to travel as easily to get up to speed on the new unit. That’s why we have started with a better stronghold here in the US because we could reach those instructors easily.

We are starting to get some interest in Europe and have a few divers using the unit there, but it’s limited because the unit is not currently CE approved. This may be something we pursue in the future for a bigger expansion.

I’ve heard that the cost of CE testing is somewhere between US$50,000-US$100,000.

We have gone through CE testing for many of our products over the years and based on those experiences, the figure is more on the high end of your range. It is a lot harder and more expensive for non-European companies to do as well. The issue is that you have to pay for the testing to be done at a European facility most of the time and then do all the paperwork and the documentation to their liking. A lot goes into it besides what the test house does, which adds even more to the cost

We do know that Rebreathers require proper testing before divers can trust them with their lives. We’ve done all the main CE tests through a third-party testing facility here in the US called Dive Lab. We have a blog on our website that has all the results from that and some pictures of it going through testing if you want to take a look at that. That would be in addition to the hundreds of actual dive hours on the unit by our in-house test divers, myself included.

Another neat aspect about our relationship with Micropore, is they actually have an American National Standards Institute (ANTSI) testing machine on site. We do a lot of testing there. Every time they do a production run of scrubber material, they do a quality control check of the scrubber material in a Dive Rite rebreather, whether it’s the back-mounted O2ptima or the CHO2ptima, in the ANTSI testing machine. I don’t think many other sorb companies are testing their product in an actual rebreather for quality control after a production run, which is kind of cool.

It is! What agencies support CHO2ptima training?

A number of them, though I would say that TDI and IANTD are the main ones. Most of the instructors have a TDI or IANTD qualification, and some have additional ones on top of that. I know that we have a couple of PSAI instructors and a few PADI instructors that can teach Tec 40 and up on the unit. Global Underwater Explorers (GUE), of course, only teaches its specially configured JJ-CCR and the RB-80.

Interestingly, the CHO2ptima is actually broadly compatible with GUE’s CCR configuration i.e., two diluent cylinders in doubles configuration with a long hose and secondary in addition to the loop, when worn with doubles. (See “The Thought Process Behind GUE’s CCR Configuration”)

I dive a DIR configuration on my doubles kit. You’re looking at a card-carrying Fundamentals diver, though I haven’t done anything past that, but I dive a DIR setup for sure. With the CHO2ptima you can easily dive it in a DIR configuration. And probably a little bit easier than you can even with JJ-CCR. It’s a lot easier to deploy a long hose—you don’t actually have to bail out to deploy it with the CHO2ptima, which we’ve already known has caused issues. There have been people that have flooded units in the process of trying to donate gas.

Jared Hires diving the CHO2ptima with back mount doubles

Practice, practice, practice, right?!? We covered the development and working of the CHO2ptima. Talk to me about some of the exploration that’s being done. I know that people like Steve Lambert are doing some incredible new stuff at Peacock Springs. [See: The Taming of the Slough: P3 Edition]. Talk to me about some of the projects people are using these for.

We’re lucky. People like Steve are doing some really cool stuff with the unit. He’s was one of the catalysts that helped push the ChO2ptima over the finish line when he came to work for us. He was excited about using the CHO2ptima just like Dad and a couple of the other guys were. He volunteered to be one of the test divers and immediately started doing big dives with it. 

He’s been doing some great exploration and has gotten a couple of his buddies from Karst Underwater Research (KUR) and “Beyond the Sump” into CHO2ptimas. They just came back from that expedition in Huautla (See: Sump Potion No. 9). They had two divers on CHO2ptimas, one on a KISS sidewinder, one on a JJ-CCR and two of them on Fathom units. So the CHO2ptima was well represented down there and they were doing some awesome dives with that. 

They’ve been working hard in Peacock and exploring in Peacock 3 down deep in Henley’s Castle. They also did some really deep exploration at Chaplain in early 2021, which is another deep spring up here and I was lucky enough to do one dive with those guys. It’s 55 m/180 ft deep for most of it—a deep river cave. We also have people who are doing deep ocean dives with them. Ben Lair, one of our CHO2ptima instructors based in Arizona, has done a number of deep wrecks in the 92 m/300 ft plus with the unit. So, there definitely are people that are doing some cool stuff with it. It’s not just doing tourist dives, that’s for sure.

Diving the CHO2ptima with a sidemount configuration. Photo courtesy of Fan Ping.

And how about Lamar? Wasn’t he planning to use one at Cow Springs?

Yeah, Cow was one of the big ones that he wanted to do. And he’s gone back and has definitely checked out those leads that the CHO2ptima was designed for. Unfortunately, I guess he let the cat out of the bag to a couple of his friends that also went and checked out the leads before he could.

Ha! I guess you have to keep your mouth shut in cave country! Thanks for taking us through the unit, Jared. Wishing you continued success with your rebreathers.


See our companion story, Taming the Slough: P3 Edition by Steve Lambert


Additional Resources

TDI blog: BUILD IT AND THEY WILL COME (CAVE DIVING): AN INTERVIEW WITH CONSUMMATE UNDERGROUND GEARHEAD LAMAR HIRES by Michael Menduno

CHO2ptima Reviews:

PodDiver Radio: Optima CM: Chest-mounted CCR Review

Dive Addiction: ChOptima ECCR Review (Dive Rite Optima CM)

The Dive Locker: Chest-mounted Rebreather Dive! Choptima (O2ptima CM) Action!

For more information on scrubber cartridges: Micropore


Michael Menduno/M2 is InDepth’s editor-in-chief and an award-winning journalist and technologist who has written about diving and diving technology for more than 30 years. He coined the term “technical diving.” His magazine “aquaCORPS: The Journal for Technical Diving” (1990-1996) helped usher tech diving into mainstream sports diving, and he produced the first tek.Conferences and Rebreather Forums 1.0 & 2.0. In addition to InDepth, Menduno serves as an editor/reporter for DAN Europe’s Alert Diver magazine, a contributing editor for X-Ray mag, and writes for DeeperBlue.com. He is on the board of the Historical Diving Society (USA), and a member of the Rebreather Training Council. 


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Cave

The Taming of the Slough: P3 Edition

Explorer Steve Lambert reports on the latest exploration push at Peacock 3, aka P3, in Wes Skiles Peacock Springs State Park, enabled by long range scooters, CHO2ptima rebreathers, electric heat, and a deco habitat with scrubber. Having teamed up with Karst Underwater Research (KUR), Lambert and friends have now pushed P3 penetration to 2286 m/7500 ft, at depths to 61m/200 ft with run times in excess of 5-6 hours. Scoop that booty!

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By Steve Lambert. Header image: P3 deco habitat at 6m/20 ft by Fan Ping. Images courtesy of Steve Lambert unless noted.

Peacock Springs in North-Central Florida is almost synonymous with cave diving. Since the dawn of the sport, divers have been exploring the beautiful blue sinks that now make up Wes Skiles Peacock Springs State Park. Many of the household names in cave diving took part in the exploration of the system in the 60s and 70s, and even more well-known names did the full survey in the 90s. The last significant exploration was done in 2010, when Agnes Milowka and James Toland connected the system with Baptizing springs, adding over 3,084 m/10,000 ft to the total length of the system. 

My first experience with Peacock 3 (P3) was during my full cave course with Reggie Ross, the former training director for the NSS-CDS. I stood near the system map tucked in the corner of the Peacock 1 (P1) parking lot, shivering in my 5 mm wetsuit and kicking myself for being too cheap to fork over the money for a drysuit while listening to Reggie explain what to pay attention to while diving a siphon. I vividly remember the deep tunnel sticking out to me, thinking it didn’t belong with the rest of the park. It was strange to me that a system so big would have such a drastic and seemingly random change in depth. Of course, at that time, I didn’t have a “feel” for what caves do. I just thought it was strange. 

Several years later, in May of 2019, Paul Heinerth and I decided to go for a dive past the restriction at the bottom of Hendly’s Castle. Paul said he hadn’t been back there in years, and it sounded like an intriguing dive to me. Coincidentally, that morning we ran into James Toland while gearing up in the parking lot. He had the end of the line in the deep section and shared with us how to navigate through the restriction and what to expect in the passage below. When I curiously asked him why he turned when he did, he said he wasn’t able to see because of how silty the area was. 

Using Sidewinder rebreathers and trimix, Paul and I swam down to the bottom of Hendly’s Castle and, thanks to James, we were able to find our way through the restriction and into the lower section. The passage was stunning. Incredible Goethite formations blanketed the ceiling, like nothing I had ever seen. Intensified by the subtle narcosis overtaking me, I was awestruck at the unique features of the passage. We swam at an enjoyable pace, assisted by the slight siphon. I was floating along the line with Paul just behind me, soaking up every second of the dive, when all of a sudden I was greeted by a “Saber” arrow at the end of the line. 

I was in disbelief that we had reached such a remote place so easily and unintentionally. Suddenly, James’s words stuck out to me—“because I couldn’t see.” I was hovering there, and I could see. A decompression penalty was piling up and I knew I couldn’t stay long, but I could not pass up the opportunity. I scrambled to tie in my safety reel and set off. James had tied off at what seemed like the end of the passage with the right side tapering off into mud, but the left side looked promising. The flow had to be going somewhere. 

I headed off toward the left where there was a breakdown pile. The silt I knocked up seemed to be sucked into it. I could tell that was where the water was going. As the adrenaline of seeing something new coursed through my veins, I decided to “modify” a few things and see what was going on. I shoved a few pieces of breakdown to the side, stirring up clouds of fine clay silt but opening up a space just big enough to fit my head and shoulders into. I saw black. A hill was sloping upward and above it was only darkness. I wiggled forward, but the scrubber cans of my sidewinder prevented me from getting any further. The silt was beginning to obstruct my view, and I watched as the promise of finding something new was overtaken by a gray cloud of silt. 

Suddenly fear started to creep into my mind—that little voice that says, “think about how far you are from home, and now you are in zero vis in a passage you aren’t familiar with.” Excitement morphed into fear, and I quickly spooled up my safety back to the main line, in a hurry to be back to where I could see Paul. We swam back to the cavern and swam in circles to stay warm as we did our deco. The dive was 5 hours and 45 minutes. I finished cold and tired, but excited for the potential of what might lie beyond the breakdown. 

My Return to P3

During the two years before I returned to P3, that darkness was always in my head. I tried getting several buddies to come with me to take a second look at the area, but my story wasn’t convincing enough to get lazy divers to “swim like a peasant” in a place where DPVs are not allowed. During these two years an important piece of this story was born, Dive Rite created the chest mounted CHO2ptima rebreather. 

 Jefferson Joel Marchand decompressing in comfort. Notice the scrubber canister.

In April of 2021 I was finally able to find a diver who feared neither deco nor swimming; Zeb Lily was in town and I conned him into going with me. Not sure if I had embellished my own memory in the past two years, I anxiously swam back to the breakdown choke. I could see the black hole where I had “adjusted” several large rocks on the previous dive. I persuaded a few more pieces of breakdown to identify as positions to the right and left of their natural state, and with my CHO2ptima, I was able to squeeze through. While in the breakdown, I could feel the flow intensifying and continued to wiggle forward, trying my best to stay ahead of the silt cloud I was creating. At the same time I was memorizing the shape of the passage so I would not panic while trying to find my way back through the restriction in bad visibility. 

The moment I popped out into an absolutely massive room was surreal. Visibility was markedly better than in the passage, and the temperature was noticeably warmer. Even with the improved visibility, from right to left my light did nothing to penetrate the darkness, and I was following an upward slope into the unknown. It was one of those rare moments when exploration goes exactly how you want it to. Instead of pinching off in some sort of death trap, the cave went onward. I savored the moment and did my best to find the way on, but the passage was so massive I was disoriented. I swam in a zig zag until my reel ran out of line, and tied off at 41 m/135 ft on the left wall of what seemed like a massive debris cone. 

I surveyed out and Zeb and I exited, ecstatic that we had found something new in such a thoroughly explored system. Once again I thought of what James Toland had said when he and Milowka connected Baptizing to Peacock back in 2010. “Many divers from the Florida cave diving community are focusing on exploration around the world, but I think it’s important to focus on exploration in our own backyard – a little something I like to call tailgate diving,” he said. “There is still a lot of cave here waiting to be pushed, and with the evolution of dive gear and divers alike comes the ability to do deeper and longer dives. This opens up new and exciting opportunities that were overlooked or never considered in the past.”

More Cave To Go

After Zeb and I discovered that the cave continued, I ramped up my efforts to recruit buddies for exploration at P3. On the next dive, we continued from where I had tied off at the top of the 41 m/135 ft mound and continued downward, back to 55 m/180 ft, where a spring vent was coming out of the wall. I remembered having heard people speculate that Lower Orange Grove was tied to P3, and was very excited. The entrance was too small to go into without advanced planning, so we tied off and surveyed out from there, but the springing passage certainly had our attention. 

On the way out of the massive room, while going back through the breakdown restriction, I noticed that the flow from the newly discovered room and the flow form the previous EOL was combining, and going off in a different direction through the breakdown. I quickly grabbed my reel, and proceeded to empty it into the siphoning passage. I turned the dive with an empty reel and safety spool, extremely excited that we had located the continuation of the siphon, and ended in a large passage. The next dive was going to be good.

The next dive was one of the best I’ve ever had. Adam Hughes and I arrived as the gate to the park opened, and we pushed off shortly after. Worried about what kind of decompression obligation we might encounter, we swam along the 61 m/200 ft passage as fast as possible. Arriving at the end of the line in a borehole passage, we soaked up every moment, as it is a rarity in modern Florida cave diving. We slowed down to a relaxed pace and savored each foot of line that emptied off of our reels. We navigated through a large bedding plane and ended up in a springing passage. The visibility was perfect, but the passage seemed to get smaller and smaller. Eventually we had to tie off, realizing that the passage was probably an in feeder, and not the continuation of the siphon. We surveyed out and completed our decompression for a six and a half hour dive. 

We started our next dive beelining for the EOL. Right before the spring vent, we found where the siphon continued on. We tied in and once again slowed down to enjoy the exploration. The passage was big, and the flow was strong. In a few fleeting moments of perfection, line fell off the exploration reel effortlessly, as the siphon pulled us deeper into the earth. After 244 m/800 ft had disappeared, the passage once again seemed to pinch off. Following the flow seemed to take us to a hole in the ceiling, once again pinched off by breakdown. 

Photo courtesy of Fan Ping.

We pushed and pulled, and rocks began to drop down on our heads. The hole was about 0.6m/2 ft wide, and after a decent workout, we had a mound of large rocks under the hole. I poked my head up and could fit my shoulders through, but because of our “modifications” the visibility was reduced to almost zero. I felt with my hands, and it seemed like once again we had broken into a room, and I was excited to come back to confirm our findings. The increasing flow of the siphon made the journey back to the cavern quite difficult, and I began to realize that at around 1,372 m/4,500 ft of penetration at 55-61 m/180-200 ft of depth, we had come close to the limit of what was possible on a swim dive. Our lungs burned from the hard work we were doing at depth, as well as the long exposure to high PO2. We were going to need help. 

A Little Help From My Friends

I had been talking to Brett Hemphill with Karst Underwater Research (KUR) about the new find, and after explaining our situation, we decided it was time to put the project under the KUR permit. The permit would allow us to continue the exploration and documentation of the system while utilizing more tools to increase our safety and efficiency. The permit would also allow us to stay in the park after hours, as the dives were getting to a length that did not allow us to complete them within the regular park hours. 

Having the backing of KUR, and the tools that come with it, we were able to make quick progress of the exploration. Jefferson Marchand was back in town from the Dominican Republic, and the two of us made the project our priority, diving every weekend we were able. While some dives ended with confusion, most of them ended with empty reels and smiles. 

The cave alternates between borehole passage and large dome rooms choked by breakdown. The passage is mostly in the 58 m/190 ft range, and the tops of the debris mounds in the rooms usually go to around 46 m/150 ft. Each time a room is encountered, divers have to wiggle through breakdown restrictions to get both in and out of the room, which makes the dive technically challenging, especially considering the amount of equipment required to be carried by the divers. 

The author’s dive profile. #Gabe says

There comes a point when a dive has such unique challenges that equipment doesn’t exist to meet them. Luckily, KUR has more than a decade and a half of experience with these kinds of problems, so Jefferson and I were able to draw on their experience to develop solutions and keep exploring. We bought a 1364 l/300 gallon intermediate bulk carrier (IBC) container and turned it into a habitat, which Brett Hemphill helped us to install in the cavern. 

With help from Andy Pitkin, Matt Vinzant, and Daniel Vickers, we built a habitat scrubber, which made the long decompressions much safer. It had the added benefit of allowing us to remove all of our equipment and relax while staying warm. In the habitat we could eat, drink, watch movies, and chat. We also created very large battery packs in case of a flood during the in-water portions of the deco and a two-way telephone system that allowed easy communication between divers and surface support. 

Dive Rite was a very big supporter of the project. Our equipment was built with the aid of their facilities, and in addition to sponsoring much of our gas, they helped with scooters, staged rebreathers, and regulators for safety bottles as well. It would not have been possible for us to acquire the massive amount of equipment necessary for the exploration without their help. 

“The current end of line is around 2,286 m/7,500 ft. At the peak of our efforts, we had over 20 safety bottles staged in the cave and the dives were running up to 12 hours—even with a relatively aggressive profile.”

Unfortunately, Jefferson had to return to the Dominican Republic, and things I had been putting off were catching up to me, so progress came to a temporary halt. We were also having trouble with our staged safety bottles in the back of the deep section corroding much quicker than expected. We lost gas due to corrosion in several bottles after only three months. 

During this pause, we have been formulating a plan to deal with the increasing demands of the dive. This summer of 2022 we are gathering a group of people who have the experience on sidemount rebreathers to do such a challenging dive, and who will commit to the project. We are also hoping to prepare a second habitat to put somewhere around Hendly’s Castle to further increase our safety margin. 

We will be making further attempts to locate the resurgence in the river and push from that end. As the crow flies, there is still almost 2438 m/8000 ft between our end of line and the river, and caves usually don’t go in straight lines. No matter what happens, it is going to be a massive undertaking and will require a full team of push divers and support divers to make the project a success. 

Just like in the 90s when Mark Long was the first person able to explore the system, because he was the first to have tanks big enough to give him the required gas for such an extreme dive, we were only able to continue exploration in this section because of the current diving technology including; long range scooters, removable chest-mount rebreathers, habitats and habitat scrubbers, dry suit heat, waterproof tablets for entertainment, and last but most certainly not least, reliable dive computers that can accommodate multiple gasses and adjustable algorithms was available to us. 

I shudder to think about how little cave might be left in Florida if Woody Jasper and the other incredible explorers who came before us, had access to the equipment we are using today. 

I shudder to think about how little cave might be left in Florida if Woody Jasper and the other incredible explorers who came before us, had access to the equipment we are using today. If all goes well, we will use the incredible tools we have access to today to push the cave until the connection to the river is confirmed.

Additional Resources:

Ezine Articles: The Taming Continues: The Peacock to Baptizing Connection by Agnes Milowka & James Toland

Cavesurvey.com: Peacock Springs

NSS-CDS bookstore: THE TAMING OF THE SLOUGH – HISTORY OF PEACOCK SPRING by Sheck Exley


Steve Lambert lives in North Florida where he works at Dive Rite and is actively involved in the exploration and survey of underwater caves with Karst Underwater Research. He frequently joins expeditions with Beyond the Sump and Hole Patrol. His hobbies include quitting when things get too hard, residential construction, and compiling Kpop playlists.


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