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I returned late last night from DEMA and have spent most of today (Monday) going through the 100+ messages in my inbox. I haven't even had time to unpack yet. I just wanted to throw out a couple of comments about the meeting and some of the messages I've seen posted: By far the highlight of the meeting for me was finally putting faces on many of my 'net buddies. I was happy to see so many techdiver "regulars" in attendance. The most amazing aspect was how young everybody is!!! Next year we should set aside an evening to get together for dinner or something. The biggest downer of the meeting for me was that I was so damn busy that: 1) I didn't get to spend much time conversing with people directly; 2) I missed most of the sessions that I REALLY wanted to see...(I ordered a complete set of audio tapes of the show); and 3) I managed to slip in a total of only 9 hours of sleep over the 5-day period (and consequently was a zombie for most of the show). I want to commend David Story for doing an EXCELLENT job of chairing the session on the various network resources for tech divers. I mumbled some blurb about the TechDiver list, but I can't remember what I said (Like I mentioned, I was a zombie...) Roger Carlson credited me for first suggesting that AquaCorps had become "Wired goes diving"...Alas, it was not I who noted the parallel between the two publications....though I can't now recall who did first make the connection... Roger also mention something about my big "secret". Actually, I had not intended it to be a secret at all: Many of you have known for some time that Cis-Lunar has loaned me two of their Mk4 rebreathers for use in my work on deep coral reefs. I told numerous people by private email about this, but asked that they "keep it under their hats" until I had a chance to ask the folks at Cis-Lunar if they had any reservations about me making this public. Any of you who know Richard Nordstrom or Bill Stone know that they are both extremely busy people, so I didn't have the opportunity to ask until I saw them at this meeting. Also, I didn't really see a need to make any sort of public statement just to say "I have rebreathers, eat your hearts out" (though I have shared my opinons on several threads involving discussions on rebreathers). Since Cis-Lunar has no reservations about me making it public, and since there seems to be a bit of discussion of various rebreathers on this forum, I figured now's about as good a time as any to post a report of my experiences so far. Last August, I was invited by Bill Stone to join Kevin Gurr and Jim Booth for a week of rebreather training at Bill's house in Maryland. As you can probably imagine, it was a technical diver's dream come true...we spent the first 4 days, all day long, in Bill's garage breaking down five of the nine existing Cis-Lunar Mk4 prototype rebreathers to their basic components, then reassembling them from the ground up. This was, for us, far & away the BEST way to learn & understand the systems. We followed this up with several introductory dives at Dutch Springs and in a large swimming pool (about 8-10 total in-water hours for each of us). Kevin & Jim took one of the units back to England with them, where they have been giving introductory one-day "Rebreather Experience" dives (see earlier techdiver postings for more details). Two other units were sent to me here in Hawaii late last year for use in deep reef exploration. I have logged just over 50 hours on the rigs, most of which has been conducted in the 20-130 fsw range. John Earle, the most skilled and experienced diver I've ever had the pleasure of diving with, is my rebreather diving companion and is using the other unit. We have set-up a self-imposed, fairly conservative training schedule for becoming familiar with the operation of the units. We had both become extremely comfortable operating the rigs, both in fully automatic and fully manual modes, in our first few hours of underwater time. Nevertheless, we are continuing to limit ourselves to our conservative self-training schedule. The deepest I've been on the unit so far is about 240 feet. Over the month of February, John and I intend to log another 20 or so hours in the 200-250 fsw range. By March, we will begin extensive explorations of the reefs and ledges in the 300-400 fsw range, our primary target depth. I also intend to conduct a few dives in the 400-600 fsw range this summer. As many of you have heard, Cis-Lunar built fully-redundant rebreathers for cave diving operations. They made 4 fully redundant rigs, but soon discovered during training dives that complete redundancy (i.e., 2 breathing loops, 6 computers, 4 cylinders, etc) was overkill, even for their extreme cave diving operations. Thus, they decided to strip the 4 redundnant rigs down to 8 single rigs (they built a 9th from spare parts), and relied on open-circuit for bailout. Both of the rigs I have are single-configuration (although I could combine them to form a single redundant rig). There are two "onboard" 15cuft cylinders, one with O2, the other usually with heliox-14. These are enough to last for any dive we'll ever do. For bailout, I have a 30cuft "offboard" cylinder with Trimix (14% O2, 60% He, 26%N2) for open-circuit (OC) bailout from depth, and another 30cuft cylinder of air for additional OC bailout at 140-70 fsw. These last long enough for me to send an emergency float to the surface signaling the need for more OC gas supplies (the boat sends me down twin 80s with nitrox-50, and later provides surface supplied O2). I also have an offboard O2 cylinder for redundancy. The air cylinder also serves as nitrox diluent during intermediate decompression in closed-circuit from deep heliox dives. All offboard cylinders (except a small amount of the air) are only used for OC bailout, and are full at the end of the dive (we've never needed them, except for OC bailout practice runs). I've seen a lot of information and misinformation posted about the functional capabilities of the Cis-Lunar Mk-4 rebreather. I've decided not to chime in, because the information provided by Kevin Gurr, Chris Hellas, and others has already cleared up a great deal of confusion. Also, I am legally bound to not disclose much of the design specifics. If people have specific questions about the functional capabilities of the Cis-Lunar Mk4, by all means feel free to ask. I may not be able to disclose many of the details, but I'd be happy to share whatever information I can (unfortunately, almost all of the really good stuff is proprietary). Right now, I can tell you that: *Yes, it can recover from a complete loop flood (I've done this 6 or 7 times already for practice/training, and have continued to dive in fully automatic mode for 3-4 hours afterward...the scrubber material was bone dry on inspection afterward). *Yes, it does have triple-redundant computers, any one of which can operate the rig in full-automatic mode. *It can *easily* be operated in full-manual mode even if all three computers go down (John and I have both done this extensively for training purposes). *Yes, it does have real-time decompression computation (i.e., not just look-up tables) *Yes, PO2 setpoint and diluent gas can be changed by the user during the course of the dive (the computer allows user-interaction through an extensive menu system). As for my personal opinions about the rig...all I can say is that I am **EXTREMELY** pleased and satisfied. A few months ago, this opinion would have been biased by the fact that I desperately wanted Cis-Lunar to obtain the necessary funding to build the Mk-5 production rebreathers (I was the very first person to give them a downpayment check last year when they announced they were going to sell them). Now, however, I know that production of the Mk-5 is well underway and I have no doubts or concerns about whether I will get my Mk-5. A few months from now, my opinion will be biased by the fact that I will own some stock in Cis-Lunar (I'm presently in the process of getting together some money to invest in the company). At present, however, I can say with confidence that my endorsement of the Cis-Lunar unit is completely sincere and without bias. :-) I honestly DO NOT want to get dragged into a politically charged debate of the various pros and cons of different rebreather manufacturers and designs. Different rebreathers have different capabilities and are useful for different tasks. After getting more information on the different rebreather designs at the recent Tek95 meetings, I can say with great confidence that the Cis-Lunar unit is the only rebreather I would be willing to spend large amounts of money on (for what it's worth, the Mk-5 is scheduled to sell for about US$15,000, which is considerably more than my annual salary after taxes.) This, however, is my personal opinion, and I do not intend to serve as a spokesman for Cis-Lunar...different people will be better-off with different rebreathers. I've heard a few complaints about certain aspects of Cis-Lunar's design, some of which are valid; most are not. I have had long discussions with Bill Stone and Kevin Gurr about the design specifications of the Mk-5. I am unable to reveal any details at this time, but I do know that ALL valid complaints of the Mk4 (e.g., size & bulk, operational complexity, etc), including a few suggestions of my own, will be dealt with in the Mk-5. I sincerely apologize if the preceeding has been too long or sounds too much like an advertisment. I will be happy to answer any questions that I can, but will otherwise refrain from "plugging" the Cis-Lunar Mk-4. 'nuff said. Aloha, Rich deepreef@bi*.bi*.ha*.or*
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