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.

Ester Medley of Centralia, Washington Bowls a 244!

Centralia Washington is most known to technical divers as the home of the “Meg hatchery” where the Megalodon rebreather is made. It turns out, however, that it’s also the home of Ester Medley, a Ninety-four-year-old woman who managed to bowl the most impressive score of 244 yesterday.

Now, a bowling score of 244 is impressive no matter how you look at it, but it’s nothing less than astonishing when you conceder the fact that Medley is legally blind!

It takes teamwork though. Since she can’t see directly ahead of her, she depends on her 86-year-old husband to tell her which pins are still standing after she rolls the first ball. Everyone sees something when they close their eyes… I can only imagine Ester Medley sees a bowling alley.

In this impressive game, Medley threw eight strikes at Fairway Lanes in Centralia, and managed the second-highest score of the year for her senior league. Way to go Ester!

“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

Rebreather Evaluation – Part 5: My Decision

In the end, the Meg ended up winning the day. There are a lot of reasons for this. The Meg is an outstanding rebreather in just about every way, but perhaps the most compelling reason for my decision was the fact that most of the people I tech dive with regularly are using them. This is not to say that getting a unit simply because your friends are diving it is a good idea, but there is really something to be said for all members of a team using similar equipment.

After picking up my Meg and completing my training with Leon in Centrailia, WA last month, I continue to feel good about my decision. When he starts talking about the Meg, Leon sounds like a proud father, and the amount of thought and planning that has gone into every aspect of this outstanding rebreather becomes more and more evident each time I dive it. I am particularly impressed with the water traps in the “T” pieces and the drain valve in the exhalation counterlung. Assuming you aren’t doing summersaults, it seems virtually impossible for water to enter the scrubber canister.

I’ll be anxiously awaiting the Apecs 3 software which will have constant PO2 decompression software built in. Leon has established a relationship with deco guru Bill Hamilton, and word around the campfire is that the algorithm in Apecs 3 will be written by the man himself!

I’m still flying with clipped wings though because my VR3 does not do constant P02 deco. I have one of the original square VR3’s that came from OMS, and Delta P is telling me that there is no way to upgrade the code to do constant P02. That sounds a little fishy since I remember buying it with CCR constant P02 as an option. It kind of seems like someone is looking to sell another VR3. Weather I buy another VR3 or simply upgrade to Apecs 3 depends on the how much the Apecs 3 upgrade will cost. I can certainly see some benefit to having everything built into one nice package, but the redundancy you get from having a constant P02 VR3 hooked up to its own independent cell makes for some really nice fault tollerance.

I’m really quite happy with my Meg, and I’m really excited to start putting some hours on it. I thoroughly enjoyed Leon’s training program. I was able to meet some great new people, hang out with some old friends, see Ron, whom I had not seen in years, and meet a new dive buddy who lives near my home.

Rebreather Evaluation – Part 4: The Megalodon >

Rebreather Evaluation – Part 4: The Megalodon

The Megalodon is made by Inner Space Systems, and is the brainchild of ISC owner and CEO Leon Scamahorn. I first got a chance to see the Megalodon on the Nautilus Explorer after a friend had bought one, and I was very impressed. It is a very serious looking unit and has a distinctively hand-made, one-off feel to it.

Unlike the other units I evaluated, the Meg is completely modular. There there are some standard configurations, but in the end, nearly everything is an optional addon to the basic envelope. It is built on the foundation of the outer housing, which is essentially an aluminum cylinder containing the standard axial scrubber, oxygen cells and electronics package. Two nice displays are attached to the head, as well as an optional HUD. Since the outer housing is constructed of aluminum, it is very rigid, giving you a number of options when it comes to attaching your oxygen and diluent bottles. The one I like best is the Tiger Gear setup, whitch provides a very elegant and tough mount.

The hoses, ADV and front-mounted counterlungs are all extremely well made, and the design on the unit gives it a very low profile. Leon spent 12 years with the Army Special Forces and it’s clear that he has built the unit with his military background in mind. The first thought that comes to mind when you see the Megalodon is that it is both incredibly rugged, and user friendly. The displays are large and easy to read, and apparently they tested the resiliency of the unit by dropping it from five feet onto a concrete floor. When a component broke, it was made stronger. When they were all done, the Meg was fine, but the concrete floor was broken. Did I mention that this unit is built to be tough?

The ISC website has a really nice breakdown of the Meg.

The list of things I like about the Megalodon is fairly long and detailed, but I’ll try to sum it up as best as I can:

  • Solid construction
  • High quality materials – Alluminum, ballistic nylon, acetal, etc.
  • Water traps EVERYWHERE
  • Corrosion resistant
  • Easily readable handsets
  • Low porfile
  • No housing / shell nonsense
  • Batteries sealed off from the breathing loop
  • Modular design – Mount any cylinders, use any backplate / wing.
  • Ability to use any scrubber you like – Megalodon, CisLunar, Extendair, and an SMI Prism.

There aren’t really many things I don’t like about the meg, but there are a few points I think might make it a little better.

  • I wish it had a radial scrubber. While you can use the CisLunar or SMI Prism scrubbers, you have to purchase these seperately if you can find them.
  • While the electronics package is great, it is only a loop controller. I wish the unit had the ability to do integrated deco calculations. This feature is coming in the next version of the software, but I would imagine that it will be a costly upgrade.
  • I would like to see a slightly more readable HUD. It is only one LED that blinks codes for each sensor. This is fine once you get used to it, but the SMI Prism has a slightly better HUD in my opinion.

That’s about it. Like I said, these aren’t really complaints, but more of a wish list. The Meg is, after all, the unit I decided to get for myself.

The following are the additional options that I decided to get on my Meg:

  • ADV (Automatic Diluent valve)
  • HUD
  • Mixed Gas Bypass – A must for TRIMIX, it provides the option to plumb in off-board gases
  • Faber 20cf Steel bottles
  • Stainless Steel back plate with continuous loop harness
  • Drive Rite Aircel TREK wing

As I believe it will result in a system that runs with much less moisture, I have every intention of trying to find a CisLunar radial scrubber at some point. This is by far, the most advanced scrubber design ever seen in the world of rebreathers. For the time being, however, the standard ISC Axial scrubber should be just fine.

Rebreather Evaluation – Part 3: The PRISM Topaz >
Rebreather Evaluation – Part 5: My Decision >

Rebreather Evaluation – Part 3: The PRISM Topaz

I had seen some photos of the PRISM coming back from DMEA, and it wasn’t too long before I started to hear some very positive things about it. In fact, one of the divers I admire most decided that the PRISM was the rebreather for him. Ergo, I decided that my rebreather evaluation would be incomplete without a good long look at the PRISM. Here are the PRISM specs, as well as a nice teardown of the unit.

PRISM stands for Peter Ready’s Incredible Steam Machine. Peter is, of course, the father of the PRISM, and head of Steam Machines Incorporated (SMI). Not only is this system incredibly well designed, it has two very nice features not found on either the Inspiration or the Meg. The first, of these, and the one that has everyone buzzing is the analog secondary display.

Sometimes called “the brick”, PRISM secondary gives a readout of battery voltage, as well as a PO2 reading from each sensor. “Big deal” you say. Every CCR on the market can do this, right? Wrong! The thing about the PRISM’s analog secondary that makes it so special is that it draws its power directly from the O2 sensors, and can continue to function even in the event of a total electronics failure. It is for this reason that the PRISM takes special, high output oxygen cells. Very very cool!

The second unique feature that the PRISM has to its credit is a radial scrubber. Unlike the more typical axial scrubbers in which the breathing gases move from top to bottom (or vise-versa) through the scrubber, the radial design moves the breathing gases from the middle to the outside (or vise-versa) through the absorbent.

TheRebreatherSite.nl is quick to tell us that “Only very complex tests show that the quantity of scrubber material, flow, form of the housing and many other factors determine the quality of a scrubber. Axial or Radial is not a general recipe for a good or bad scrubber.” Radial scrubbers do, however, have the added advantage of allowing moisture to condense on the much cooler inside of the scrubber bucket, thus, arguably keeping the O2 cells dry. Or at least that’s how the theory goes… It’s always hard to tell how well these theories translate to real-world experience.

The PRISM has some pretty nice other features as well. It is very light, which is nice if you have to hike to your dive sites. The solenoid exists outside of the breathing loop, meaning that it would not affect the PO2 of the breathing loop should it leak. The heads up display is by far the most well developed of any on the market, and there is an even cooler one as vaporware that will give a digital readout. The PRISM also has an optional shell if that is your kind of thing.

So what are the downsides? Well, in my mind, the fact that the analog secondary display relies on jeweled movement is a pretty serious problem. In the end, this is a millevolt meter that has been waterproofed and calibrated against the high-output O2 sensors to read PO2. As an electronics geek, I can testify that these millevolt meters break pretty easily when subjected to a shock. Even though I love the idea of being able to read my PO2 independently of the electronics, I worry that “the brick” just won’t stand up to the inevitable bumps and thumps on a dive boat. I also don’t like the little wheel it uses to select the individual sensors. I do a lot of diving in cold water, and I worry that this might be difficult to operate with thick gloves on.

The PRISM is made of plastic. Is this a bad thing? Most likely not, but I’m just not much of a plastic sort of guy. There is just something about nicely machined alluminium that makes me happy, and this rebreather doesn’t really have much of that going for it. It’s nicely machined, but it’s nicely machined plastic and to me, that’s a downside. Granted, there are some very good arguments for using plastic as a material. It makes the PRISM the lightest rebreather I evaluated, and plastic is wonderful about not corroding in salt water. Will the fact that the unit is plastic be cause for concern about the durability of the unit? Who knows?

The tanks are attached via velcro straps. This is really not a problem, but it’s certainly not as cool as the Tiger Gear hard mounts found on the Meg. From everything I’ve heard, the unit is very solid when put together, but I don’t think I would be able to strap aluminum 80’s into the thing.

Finally, and most importantly, there is something that bothers me about having only a heads up display and an analog secondary as instrumentation. Sure I can tell what the PO2 is by watching the HUD, and double check it against each individual sensor by toggling “the brick”, but I really want to be able to easily see each sensor’s readout on redundant digital displays. In my opinion, SMI has taken away from the usability of the unit in every day diving by making sure you can stay fully closed circuit even with a total electronics failure. It’s always a balance, and I certainly appreciate the fault tolerance, but I think they’ve planned a little too much for the worst possible case. This is, of course, all just conjecture, as I have never even dived the thing. It’s just how I imagine it would be.

So that’s my feelings on the PRISM Topaz. Remember, I have never even seen the unit, let alone dived it, so please comment if I have made any glaring errors.

Rebreather Evaluation – Part 2: The Inspiration >
Rebreather Evaluation – Part 4: The Megalodon >

Deep Dive On A Wreck Full Of Toilets

Leigh Cunningham and Mark Andrews figure they’ve made the world’s deepest wreck dive on the Yolande, a 72m ship in Egypt which had been carrying a bunch of toilets.

The wreck sank in 1981, but slid into deeper waters because of a storm in 1985. It currently sits in water ranging from 145m to 160m, and perhaps even deeper. The two divers ventured to 160m on TRIMIX, which is admittedly a very deep dive.

The team plans to return to the Yolanda in August to dive even deeper in search of other parts of the ship. Cunningham works as a TDI Instructor Trainer, and Andrews is Technical Director at the London School of Diving.

More information can be found here.

Well done guys!