Revillagigedo Archipelago Dive Log – Day 4

With only three days left to dive on our trip, I was admittedly wishing that we had chosen another dive site for the day. My primary goal of this trip was to spend a great deal of time on my rebreather, but the swell was simply too great, and I was diving open circuit to avoid the inevitable counterlung volume issues that came along with the conditions. I guess I should come out and say that I am a technical diver and thus, the greatest draw to me is deep water and not necessarily the interaction with animals for which Roca Partida is most known. This, combined with the fact that we had seen fairly few large Mantas and Sharks on our first day here had me pining for some walls in more protected water.

John, however had mentioned the night before that we WOULD see more creatures today, and that there was simply no way around it. We joked with him that he had sent out a telepathic signal to them, and that they were surely swimming toward us now, but unlikely to arrive before our departure. We all had a chuckle at the idea of hundreds of confused Pelagics swimming around island several days later, wondering where John had gotten off to. Telepathy or not, whatever he did worked because the number of large animals we saw on day two at Roca Partida made the first day seem like diving in a sterile lake.

Because I was still diving open circuit, and had little to devote my attention to other than just diving, I decided to try my hand again at photography. Unlike the day before, but camera worked perfectly and most of my underwater shots from the trip are from this day. I even took a video of one of the Mantas that came in close and interacted with us.

The first dive of the day was wonderful. I still found myself looking down into the depths, wanting to dive to the peak of the submerged volcano at 250 feet, but the fact that we saw a large black Manta and a group of Hammerhead sharks right way made staying in shallow water a great deal easier. I actually only went to a maximum depth of 85 feet on this dive, but there was so much to keep my interest that I stayed in the water for nearly an hour.

The second dive was much the same, although I descended to 95 feet this time in hopes of finding some more Hmmerheads. I found a great number of Silky Sharks, but the Hammerheads eluded me. I ascended to around 50 feet where I had another wonderful interaction with a black Manta and found a lot of large Tuna. I finished out my 1 hour dive in the 40 to 50 foot range and enjoyed taking in the scenery.

There really is something about doing dives that don’t have a visible bottom that makes you feel like you can fly. Many of the divers described the Mantas as Sirens that call you out into the blue away from the visible topography, and I can attest that they most certainly do. I think of myself as a very disciplined diver who maintains awareness of his surroundings and topography at all times, but when a large Chevron Manta showed up on our third and final dive at Roca Partida, I was amased at how, after only what seemed like a kick or two towards him, I was much further from the island than I expected to be. This is not to say that I could not see the topography, but it made it very clear how one might get into trouble swimming with Mantas. As I was still fairly close to the island, I decided to simply hover at 85 feet in the water column and let the giant Manta make several passes at me. As an added bonus we had some large Silvertip Reef Sharks make passes by us as well. All told, I stayed in the water for an hour, and reached a maximum depth of 90 feet. It was a wonderful way to say goodbye to this amazing dive site.

That night we pulled anchor and headed back to Socorro for another day of diving. I was tired, so I slept well despite the constant rumble of the boat’s engines.

Revillagigedo Archipelago Dive Log – Day 3

Roca Partida is not so much an island as it is a small lava plug from an extinct volcano that has otherwise been eroded away into the sea. This rock pillar is only about 300 feet across at its widest point, and it descends almost vertically to a depth of 250 feet, where only then does it begin to take on the topography of a typical mountainous volcano. Situated in the open ocean, 60 nautical miles from the nearest land, the only inhabitance of this failing island are a great many birds which is evidenced by the snow-like white shrouding of all but the most wave-beaten rock. While there is not much in the way life above the surface at this site, it is known among divers for its nearly constant traffic of Manta Rays, Sharks and Tuna. Roca Partida is, in fact, generally thought to be the best dive site the Revillagigedo Archipelago has to offer.

Because of the remote and exposed location of this dive site it is important to have good weather or the swell becomes too large, and the site undivable. So, when the weather report came back fovorable for the next few days the decision was made to pull anchor and begin the 60 mile trip to Roca Partida, where we would spend the next few days diving. Because these islands have not been re-charted since the advent of GPS, the moving map displays on the ship are not always totally accurate and the crew prefers not to maneuver the boat around the tiny island at night if it can be avoided. I, myself, got somewhat confused at one point when I turned on my little Garmin GPS and found that it had me placed right on the beach of Socorro when I was quite clearly standing on the deck on the Nautilus Explorer! Anyhow, the trip would take about 12 hours, so we decided to leave Socorro for Roca Partida after dinner so that the sun would be up by the time we arrived.

To my surprise, the dive briefing that night included very little of Sten’s humor and joking, but instead a lot of stern warning about not loosing visual reference to the topography and the importance of surfacing near the island. Because it is basically an open-ocean dive site and there is no shotline, a diver that surfaces very far from the Zodiac or skiff is difficult to see, and can easily become lost at sea. While we all carried surface marker buoys (SMB’s) and mirrors to mitigate the risk, the warning was clear. “Never lose the topography underwater. If you become disoriented, surface without a safety stop and inflate your SMB.” Sten saved the most chilling warning for last, reminding us that if we became lost the only Boat looking for us would be the one we were on, and that if we were not found by dark we would not be found.

That night I did not sleep well, and woke up entirely too late to get my rebreather configured to make the first dive. Instead, I lounged around, drank coffee, and leisurely pre-dove my rig. Rich, on the other hand made the first dive and mentioned that maintaining counterlung volume was difficult above 30 feet because of the substantial swell. We both made the decision to dive open circuit at this site and I carefully packed up my Meg beneath my bunk.

My first dive of the day was great fun, but something in my brain forgot what it was to dive standard SCUBA gear, and I emptied my tank to 500 PSI after only 45 minuets in the water. You can breathe as hard as you like on rebreathers, but not so on open circuit. I had borrowed my gear from the boat, and was surprised to look down and see that my borrowed dive computer, a TUSA IMPREX, read that I was at 155 feet! My trusty VR3, a dive computer that I have depended on for years, and one that has been used on many a gnarly tech dive read only 100 feet, so that was the one I decided to trust. The IMPREX racked up quite a deco obligation, so I went ahead an cleared it while playing around in 30 feet of water or so. The 30 foot level turned out to be the most interesting anyhow because we saw a large Manta, some White Tip Reef Sharks and some large Tuna towards the end of the dive. It was difficult to maintain a constant depth, however, because of the strong surge and swell.

The second dive of the day was much the same as the first, except my camera ran out of batteries about half way through the dive and I did not consume nearly as much gas. By this time I had ditched borrowed regulator in favor of another borrowed regulator, and no longer had to suffer the greatly exaggerated depth displayed by the IMPREX. I swam a total of two laps around the island at a maximum depth of 100 feet, but saw little other than a few sharks and large groups of bait fish. The entire dive lasted about 45 minuets.

By the third and final dive of the day, it was getting dark, and again, we saw only sharks. My camera was working perfectly, but I had too little light for much other than macro shots on the rock. I did get some interesting pictures of little shark dens where juvenile White Tips would gather to rest, sometimes among Moray Eels. Again, I circled the island two times at a maximum depth of 120 feet, and the dive lasted 45 minuets.

Roca Partida did seem to be a great dive site, but at the end of the first day my feeling was that it had been hyped quite a lot. We had only seen Mantas on the first dive, and I was a little unhappy that I didn’t have any helium with which to dive down to the are where the pillar leveled off at 250 feet. The conditions were rough, but not nearly so difficult as had been let on, and a part of me wished we were not spending two days there. I had no way of knowing at the time, but the next day would do a lot to change my mind!

Revillagigedo Archipelago Dive Log – Day 2

After our last dive on “The Canyon”, we began steaming to Socorro Island. I can’t say exactly when we arrived because I was sleeping, but I seem to remember that the journey took around ten hours. Our dive site for the day was called “Puntatosca“, which was basically a series underwater lava flows that took the shape of walls. All the small details of the site are too numerous to write about, but by clicking on the little image of the whiteboard to left, you can see Sten’s masterful rendition of the site’s topography.

Actually, while on the topic of Dive-master Sten, I should say that I have never in my life experienced such detailed and thorough dive briefings. A tall and very quick-witted Sweed, Sten’s briefings were hilarious and entertaining on top of being incredibly informative!

Our first dive involved tediously pulling ourselves down the shotline against a very strong and troublesome current. Normally this would make for a difficult and disappointing dive, but in this case an incredibly friendly dolphin decided to join us as we pulled ourselves against the current. Mockingly demonstrating how easy it was for him to swim against the strong current, the dolphin situated himself next to us on the line, blowing the occasional bubble from his blow-hole, and practically begging us to touch him.

Now, of course, finding such a friendly and interactive dolphin is somewhat of a dream come true for many divers, and as the dolphin flirted with us, the already crowded and chaotic shotline became a sort of underwater trainwreck with divers packed tightly against each other. Being the big baby that I am, I admit to having some concern that my rebreather would get scratched or dinged, but it escaped unscathed, and I was forever grateful to have had such a wonderful encounter with this amazing creature.

The dolphin followed us to the bottom where the lava flows provided some protection from the strong current, but the surge was still quite strong. Rich and I followed the wall out to a maximum depth of 100 feet, where we found the surge to have let up quite a lot. We did not stick with the larger group, but they reported that they saw a group of Hammerhead Sharks. The entire dive lasted 45 minuets.

The second dive of the day did not feature such a flourish of wildlife as the first, but at a maximum depth of 140 feet it was my deepest dive yet on the Meg. I decided to do this dive alone, and descended to the bottom of the wall with the hopes of finding some sharks. in the end, however, I only managed to find a large yellow Tuna, and a lobster. I enjoyed the dive greatly though, and spent an entire hour exploring lava flows and looking into the blue beyond the wall.

The third dive of the day was much the same as the second, although we saw some large Silky Sharks. I did not descend to the bottom of the wall this time, choosing instead to swim about 20 feet above the sandy bottom at a maximum depth of 120 feet. I exited the water after 45 minuets, and decided to change out my scrubber material and skip the last dive of the say. That night we pulled anchor and headed off to Roca Partida, the smallest of the Revillagigedo Archipelago.

Revillagigedo Archipelago Dive Log – Day 1

Our first day of diving at the Socorro Islands was was on the northernmost island of San Benidicto at a dive site called “The Canyon“. This site was chosen because of its general lack of swell and current, and was to serve as a warmup to the more challenging conditions to come. We were told this particular place had the potential of being either among the best sites we would visit or the worst. Some friends that had been to the islands before mentioned that they had not enjoyed their dives at this site very much, but we were lucky enough to see a giant Manta Ray that was the friendliest we would encounter for many days to come.

My first dive at The Canyon was enjoyable, but never having used my rebreather with anything other than a drysuit, I was unsure how much weight I would need with my new 5mm wetsuit, and the 12 pounds I added made me grossly over weighted. I also experienced trouble sealing the membrane between my nose and throat, so I was constantly, albeit slightly, breathing in and out through my nose. This effectively resulted in me drinking whatever saltwater came into my mask, giving me a burning sensation in my sinuses and a queasy feeling in my stomach.

Not much worse for the wear, however, I stayed down for 35 minutes and descended to a maximum depth of 90 feet, but did not get to see the group of Hammerhead Sharks that my buddy Rich saw. All in all, it was a great shakeout dive, and seeing the Manta was a real treat. It was clear, however, that I would need to remove quite a lot of weight from my rig.

The second dive was much better, although we did not see any Mantas. My nasal membrane sealed up much better, though not perfectly, and the 6 pounds of weight I had removed resulted in much better trim. I descended the wall to a maximum depth of 120 feet, where we encountered a fairly large group of White Tip Reef Sharks. We stayed there for a while to watch them, but decided to head back after we had incurred about five minuets of decompression obligation. On the way back to the shot line, we saw a large Stingray, and a couple of Moray Eels. The entire dive lasted 45 minuets.

The third and final dive of the day was much the same as the second. By this time I had removed all the weight from my rig, and found that it was trimming out perfectly. We descended to a maximum depth of 100 feet, and encountered a group Silver Tip Reef Sharks. I had been struggling all day with finding a way to use my new Jet fins, but even diving with sneakers on, I found that my right, big toe was killing me on this dive. The problem was that fins were sized for my DUI rock boots, and both the wetsuit boots and sneakers moved around too much inside them. After this dive, I decided I would switch to my Scubapro Twin Jet fins. I only stayed down for 35 minuets on this dive because I was getting tired and my toe was hurting so much. It was a great dive though, and I was looking forward to getting some sleep and diving the next day.

Revillagigedo Archipelago Expedition

I’ve just returned from diving at the Revillagigedo Archipelago, also known as the Socorro Islands. This small and widely distributed Pacific island chain lies about 250 nautical miles southwest off the tip of the Baja California peninsula at roughly 18° N 112° W. Known for their unique ecosystem, these islands are sometimes referred to as the “Mexican Galapagos”, serving as hosts to a number of plant and animal species that are found no place else on Earth. Under threat from exotic species, the Mexican government established the islands as a Biosphere Reserve on June 4, 1994 in an effort to protect this natural treasure.

Because of the extremely remote location, only a select few dive boats are even capable of running trips to the Revillagigedo Archipelago, and of these, only two have been granted the licensees required to do so; the Nautilus Explorer and the Solmar 5. Our trip was on the Nautilus Explorer.

While we spent a total of nine nights and seven days aboard the Nautilus, it takes about 24 hours to reach the Northern most island of San Benedicto, meaning that two full days and nights must be spent at sea. This left us with five days of intense diving, usually making four dives per day, and sometimes even snorkeling with the sharks at night. Needless to say everyone slept very well at night!

The diving at these islands is really quite nice. The water temperature was running about 70 degrees F, which matched up perfectly with the 5mm wet-suit I brought with me. While the deepest dive I made was only 160 feet, I chose to dive my Megalodon rebbreather on all the dives except those on Roca Partida, which had so much surge and swell that maintaining counterlung volume became very difficult in water shallower than 30 feet.

The biggest draw to the Revillagigedo Archipelago is, of course the giant Manta rays, but for me the sharks were perhaps the most interesting. We saw countless White and Silver tip Reef Sharks, and Hammerheads were also quite common. The divemasters commented frequently that the Mantas were much more friendly in on prior trips, but a few did allow us to interact with them. For me, the most memorable experience of the trip was a very friendly Bottlenose Dolphin that swam up to me and practically begged me to pet it.

Again, because of the remoteness of the location, as well as the cost of helium in Mexico we did not make this a technical diving expedition. While there were a number of times I desperately wanted to descend below 200 feet, this trip served as a great opportunity for me to really put some hours on my rebreather, and get myself geared up for some more aggressive diving in the coming season. I find that every dive I am trusting the CCR technology more and more, and diving the unit is starting to become second nature.

Stay tuned. In the coming days I will write about each of the dive sites we visited, and the animals we saw there.

Revillagigedo Archipelago Facts

Island (Alternate Name) Length by
width (km)
Area (km²) Highest Peak (m)
Inner Islands (UTC-7, Mountain Time)
San Benedicto (San Tomás) 4.315 by 2.490 5.94 Bárcena (310)
Socorro 16.813 by 15.629 132.06 Mount Evermann (1130)
Roca Partida 0.246 by 0.073 0.014 (34)
(Outer Island) (UTC-8, Pacific Time Zone)
Clarión (Santa Rosa) 8.544 by 3.686 19.80 Monte Gallegos (335)
Revilla Gigedo Islands 420 by 115 157.81 Mount (Cerro) Evermann (1130)

“Titanbox” Titanium Frame For the Inspiration Rebreather

The Inspiration and Evolution rebreathers from AP Diving are really good rigs, but the design of their housing and harness systems have always limited the flexibility of the units to a degree. The housings are quite fragile, and because they do not use a metal backplate, clipping in side-mounts always seems to be more of a struggle than it’s worth. Top it all off with the fact that housing and harness are quite large and difficult to travel with, and you can conclude pretty quickly that there is a lot of room for improvement in the way the rebreather is attached to the diver.

Indeed, a number of enterprising divers have totally re-invented the housing and harness system. Janwillem Bech’s Travelframe is a good example of this type of innovation. It allows the entire rebreather to fit into a carry on bag, and adapts it to a Hogarthian backplate and harness system, making the use of side-mounts much much easier.

The latest in the series of these custom-made Inspiration / Evolution frame systems is called the Titanbox, and it is truly a work of art! Designer Michael Hearn at Dive Designs must be a master craftsman because the his frame is not only very well built, but absolutely beautiful as well. Hearn writes:

When I started diving the Inspiration rebreather a few years ago, I noticed the original case of the inspiration is limited when it comes to use bigger cylinders or attaching extra accessories such as battery’s.

As I was searching the web and dive shows for a scrubber assembly case, I never found what I was looking for.

So I decided to design and built my own case in one of the most indestructible, non corrosive and affordable metals of all: titanium. As titanium is very expensive and difficult to work with, I also built a hard anodized aluminium version.

He is offering them for sale, but as one might expect in the world of rebreathers, they don’t come cheap. The titanium model can be had for just under $2,000, while the allumnium version comes in at a little under $800.00. As far as I can tell it’s worth every penny though if you have an inspiration. I know I’d have my order in if I’d gotten one instead of my Meg.

Well done!

More info and tons of pictures can be found at Michael’s website.

Hat Tip: TheRebreatherSite.nl

Gas Blending System

With the help of my friend in Reno, I was finally able to get my gas blending system together and working. This system will allow me to connect nearly any type of industrial gas cylinder to any type of SCUBA or medical oxygen tank. I can even connect it up directly to banks of 4500 PSI air.

When building these systems, many people decide to incorporate quick disconnects at the supply side to facilitate quick changes in gas for making custom blends. This allows for the adaptor to stay connected to the industrial gas cylinder, while making it easy to move the whip from gas to gas. This is a great design in theory, but these connectors tend to develop leaks over time, which can be frustrating and costly, especially when working with helium.

In order to maintain the flexibility of quick disconnects without the problem of leaky connections, Keith had the brilliant idea to standardize the entire system on SCUBA DIN connectors. This makes switching source gas nearly as easy, but results in a much more solid and leak-proof connection. A male DIN connector is at each end of the fill whip, and all bulk cylinder adaptors have a female DIN connector on the whip side. Connecting up your source gas becomes as easy as screwing in your SCUBA first stage.

In the interest of being thorough, I decided to get the system with just about every type of cylinder adaptor imaginable. For the time being, I really only plan on doing transfils from industrial gas cylinders for my gas blending, but at some point I may decide to hook it up to a booster. My rebreather tanks are only 20 cf, so I can’t really justify the cost at the moment, but if I ever start making TRIMIX in anything larger, I will have to invest in some type of booster to make the helium go further.

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