Darkness Beckons

All next week I’ll be taking a cave diving class on my CCR down in North Florida. Cave diving has been a dream of mine since reading an article about Sheck Exley’s exploration of the Nacimiento Mante cave system in Mexico. At a time in my life when I almost bought into the idea that divers should not venture deeper than 130 feet, there I was, reading about a man who had plunged to a world record depth of 881 feet and returned safely to the surface after 14 hours of decompression. It was as if the wool that had been pulled over my eyes by the recreational diving agencies had suddenly been removed, and I was left totally inspired. I remain inspired to this day, and I am honored to have the opportunity to learn cave diving from legendary cave and technical diver Tom Mount.

Who Cares if the Rebreather Has Integrated Deco

For some time now, Innerspace Systems has been working on a Megalodon head called APECS 3 that supports integrated decompression. As with any major software / hardware engineering project, there have been some delays, which has Meg owners clambering for information about when it will come out. It’s amazing how so many of these rebreather divers are pestering the company and acting like a bunch of kids a few days before Christmas. What I don’t really understand is why people are so anxious.

It’s not that I wouldn’t like to have integrated deco, but I really don’t see it as being all that big a deal. When software gets more complex it also gets more buggy, which is why I’m pretty happy having a very basic loop controller. Keeping the deco on a different unit like a VR3 is a nice modular system, and besides, I don’t really even use the computer on really deep dives.

When I plan a bigger dive, I do it like this:

  • Work out the details on the laptop
  • Cut the tables and laminate them (wrist mounted slate)
  • Cut bailout tables and laminate them (also on wrist)
  • Fill 02 and Diluent
  • Fill bailout using thirds
  • Do the dive as it was planned and as it appears on my wrist.

While I use the computer to validate my deco schedule, it is really only there for backup.

Again, it would be nice to have integrated deco, but IMHO, you should not do big dives if you can’t maintain a setpoint. Provided you can, or even if you depend on your loop controller to do it, your actual setpoint will match that on your computer. Everything should jive and you can validate the deco schedule on your wrist.

It’s tempting just to jump in, do a gnarly dive and depend on your computer to get you out of it, but doing so ignores some of the basic safety precautions of technical diving like proper gas management, which is a risk that I really don’t feel comfortable taking.

Wingsuit Base Jumping Video

Bill, our DBA, showed me this video of some hardcore base jumpers who leap off tall mountains and use wingsuits to fly within inches of the cliff walls on their way down. I was entertained that the guy with the white suit looks a lot like the Jesus action figure we got my Sister-in-law for Christmas.

As with most things that are extremely dangerous, this looks amazingly fun! Some of the guys were using wingsuits when I went skydiving, but we were jumping out of planes, so obviously they weren’t doing anything like this. It makes me want to head back to Z-Hills and learn how to fly one of these suits.

Making a Connector for the Teldyne R22D Oxygen Sensor

If you dive rebreathers much, chances are you will have to repair or replace the Molex plugs and pins that connect your Teledyne R22D oxygen sensors to your head electronics. Many manufacturers are cool about sending you the parts so that you can do the repair yourself, but some, such as AP Diving require that you send the entire head back for this simple repair.

If you are comfortable handling electronics, and you think it’s silly to have to send your head all the way to England or wherever just to have a couple of parts costing less than $1 replaced, you can get the parts you need from just about any distributor that sells electronic components. I like Digi-Key because they would sell me the crystals to make a Red Box when nobody else would. I’ve been loyal ever since.

Here are the parts you will need:

Digi-Key part number: WM1129-ND
Manufacturer Part number: 08-56-0110



Digi-Key Part Number: WM2001-ND
Manufacturor Part Number: 22-01-3037



How Scuba Tanks are Made

I was trying to talk Justin into getting a set of steel tanks so that he could band them together when we got onto the subject of how scuba tanks are made. He mentioned some videos of the process he had found, and sent them along to me. It’s really a pretty amazing process. Especially the way they extrude an entire tank out of a single block of aluminum.

The first video shows how aluminum tanks are made, while the second shows the process for steel tanks.

Revillagigedo Archipelago Dive Log – Day 6

On our sixth and final day of diving at the Socorro Islands, We headed back to San Benedicto to dive at “The Canyon” and, we had hoped, another stone pillar rising up from the sea floor called “The Boiler”. By this time in the trip, the weather had turned fairly bad for Mexico, and we were dealing with quite a bit of swell. As usual, we got up and had our pre-breakfast breakfast (they feed you well on the Nautilus) and started getting ready to dive. Since this was my last day of diving on the trip, I had made up my mind to do some deeper dives on my rebreather.

Keeping in mind that I did not have access to any TRIMIX I decided that I would not go much deeper than 155 feet, which is the point on rebreathers where you really should start using Helium in your mix. This is not only to buffer the narcosis, but because going deeper than 155 using air diluent at a 1.3 setpoint causes you to actually incur more decompression obligation than if you were simply breathing straight air.

The other thing to remember when doing deeper rebreather dives using air diluent is that the effects of narcosis can be much more troubling than when diving open circuit. When you are breathing off a tank, you feel a bit of narcosis in your head and you know exactly what it is and, assuming you have acclimated yourself to it slowly and over progressively deeper dives, how to deal with it. You can accept the narcosis and go on about your dive.

On a rebreather, however, you are breathing off a recirculating loop which is monitored by oxygen sensors. You constantly check the status of this loop and you depend on the sensors to give you accurate information, quite literally, with your life. Should you have too little or too much oxygen in your loop, your body will give you very little warning before you either fall asleep or go into convulsions. For this reason, you are not only constantly monitoring your loop, but also how you are feeling. In deep water, it becomes easy to ask yourself if the narcosis you think you are feeling might actually be lightheadedness from a C02 breakthrough or impending hypoxia.

Anyhow, to make a long story short, I really wished I had some helium, but I didn’t, so I was stuck going not much deeper then 155. On the first dive of the day, Rich and I went down the shotline, snaked around the outside of the canyon wall, and headed down the gentle-sloping topography. As we descended, there were a lot of little rock platforms that came up about 10 feet off the sea floor. We made our way from one of these to the next until we finally found ourselves at the top of one in exactly 150 feet. We hung out for a while, looking at several white-tip reef sharks, but finally decided to head back up into shallower water. We met up with our friends at about 80 feet where we all started making our way back to the line. The entire dive lasted 50 minuets and it was the deepest dive I had done on my Meg to date.

The second dive of the day was supposed to be at a site called “The Boiler“, a stone pillar jutting up from the seabed, and peaking just slightly below the surface of the water. It is an extremely exposed site, and it became clear on the boat ride out that there was no way we would be diving it. At one point the skiff broke loose from the Nautilus and the crew had to go rescue it. I’m also sad to report that a very nice camera took a digger because of the high seas, breaking the dome and bending the lens. Overall, it was a very bad boat ride!

Cutting our losses, we returned to the Canyon, which was in fairly protected waters and still very divable. The Nautilus anchored directly at the dive site, so we could splash right off the back and stay down for as long as we liked. The divemasters had also rigged a trapeze underneath the Nautilus at about 30 feet, allowing divers to pull themselves from the dive deck on the stern to the main anchor line on the bow. I made my way down the line, and as before I rounded the wall and headed down the bottom, making my way from platform to platform. On this dive, I decided to go alone and stay down a little longer than before. I stopped when I arrived at 160 feet, and stayed there for about 5 minuets. As before I saw some sharks, but little else, and finally decided to head back. I saw a few other divers on my way back, but not wanting to get into too much deco, I decided to leisurely make my way back to the anchor and complete my decompression.

All told, I stayed down for an hour and decompressed for 20 minuets, adding about 10 extra on pure oxygen just for safety. Many of the other divers decided to do one more dive before we pulled anchor and headed back to Cabo, but I was happy to stay dry. My last dive had been great fun, and I thought it a great way to say goodbye to the Revillagigedo Archipelago.

That evening, we began the long, 27 hour journey back. The next day we spent cleaning gear, settling tabs, sharing pictures and videos and generally chatting about a great trip. The ocean was quite rough, so I spent a great deal of the ride back with a twinge of seasickness, but nothing too bad. We finally arrived in Cabo San Lucas at about 10:30 PM. We all wanted to get off the boat pretty badly, so a bunch of us headed out to Cabo Wabo to see if we could find Sammy Hagar, or at least some burritos and tequila. Luckily we found both, but we headed Sten’s warnings and stayed away from the police and the people looking to make “new friends”. Cabo really is just a big old party.

We made our way back to the boat by midnight, and headed out to the airport the next day at 9:00AM and just like that the trip was over. It was wonderful diving and wonderful people. I highly recommend the Socorro Islands to anyone who loves diving, and loves large sea creatures!

Revillagigedo Archipelago Dive Log – Day 5

We steamed the better part of the night from Roca Partida back to the island of Socorro where we would be diving a site called “Cabo Pierce” and another stone pillar called “La Pitite Boiler”. Normally we would have made our way to these sites on Days 2 and 3, but we wanted to take advantage of the calm weather on those days to dive the much more exposed Roca Partida. As the Captain predicted, the wind and swell were definitely beginning to pick up and the relative protection of the island was certainly welcome. By now, however, I had found my sea legs, and any nausea I had felt during the first few days had long since passed. I did, however, sleep poorly and as my eyes cracked open I found myself entirely unprepared for the day at hand. Remembering that this trip was expensive and that each diving was costing me about $150, I forcibly dragged myself out of bed, albeit too late to get my rebreather ready to dive.

So it was that I found myself on open circuit SCUBA gear again that morning, which was just as well because I was tired and groggy thru-out the entire first dive and there was a LOT of current. It’s hard to say if it was because I was tired and not paying close enough attention, or simply because there was not much to see, but the first dive at “Cabo Pierce” was fairly uneventful and my photography endeavors resulted in little other than a few pictures of fish and an Octopus. As with many dive sites at the Revillagigedo Archipelago, this “Cabo Pierce” is a lava flow that takes the form of walls. The dive site itself starts at about 80 feet, making it a fairly deep dive if your intention is to avoid decompression obligations. My maximum depth on this dive ended up being 100 feet, but I stayed down for 45 minuets and racked up a little bit of deco… I was breathing air after all.

After getting back to the boat, drinking a little coffee and eating breakfast I went to work straight away on putting my rebreather together and pre-diving it. Diving Rebreathers is a form of technical diving and it requires a lot more work and attention to detail than open circuit diving. Because of this, rebreather divers are frequently the target of taunting and snide comments by open circuit divers. You almost get to the point where you stop hearing it when people say “my, those things certainly are a lot of work”, or “seeing how much work those things are to dive, I think I’ll stick with my traditional SCUBA gear”. Perhaps they’re just jealous. Technical diving is not for everyone and since most people don’t want to do long, deep dives, they’re probably better off with standard equipment and techniques anyhow. All told, I spent about an hour getting my rig ready to dive and finished just in time to make the second dive of the day. Not wanting to fight with the strong currents we encountered on the first dive, I decided to do this one by myself and explore the lava formations inside the large cove near the island itself. I jumped right off the back of the Nautilus, descended to the sandy bottom at 100 feet and started swimming towards the island, keeping the sun at my left for reference.

As I neared the island, I found myself in about 50 feet of water, both hearing and feeling the songs of Humpback Whales. We’d heard Humpbacks on many of our other dives, but in the case, the sounds were amazingly loud and I could actually feel the low frequency waves travel through my body and head. I can only imagine that the creature itself must have been very close, but despite constantly looking, I was unable to see it. The sounds diminished as I neared the island, and I found that the shore was not so much the sheer wall I had imagined, as it was a series of walls that were formed by lava flows. I didn’t see much in the way of animals, but thoroughly enjoyed exploring the flows and lava formations. At one point I even found a small cave which started in about 40 feet of water and ended roughly 40 feet back and 30 feet deep. All told, I stayed down for 1 hour and reached a maximum depth of 100 feet.

For the third and last dive of the day we went to a site called “La Pitite Boiler”. This site is a small stone pillar that begins on the sea floor at 130 feet, and extends up to about 5 feet below the surface. It is named for the way the water seems to boil as the waves pass over it, briefly exposing the peak and then submerging it again. We descended directly to the bottom at 130 feet and basically swam laps around the towering stone getting shallower and shallower on each pass. The surface was fairly rough, but there was little to no current and the dive was extremely fun. We saw quite a few Moray eels, although the larger animals eluded us. It’s hard to say exactly how many laps I swam around the pillar, but I stayed in the water for an hour and enjoyed every second of it. When I did decide to surface, I did so mostly because I didn’t want to keep the other divers waiting and because it was getting dark. I could have happily stayed down for another hour!

We pulled anchor and started heading back to the island of San Benidicto for our last day of diving before dinner. The seas were rough, which made for some interesting displays of plate and cup handling skills during our meal. I had a couple of Gin and Tonics and headed off to bed. Since we were going back to “The Canyon” I had designs on doing some deeper dives in the morning.