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part 2 of 2

        On Monday, the final day of the show, I spent most of the day on the
exhibition floor, studying the four rebreathers present, but after Nuytten's
talks, I didn't want to miss the tek.Banquet luncheon, at which Graham Hawkes
would speak on his submersibles: the Wasp, Deep Rover, and his new concept
submersible, Deep Flight.
        Hawkes was another wonderful speaker. He warmed us up by telling a few
stories about the fun you can have with a Wasp when there are divers in the
water with you. One story was about the time he was in a lock with a diver,
since the diver was the biggest animal in the lock, he was naturally the most
fun to play with. Hawkes decided to see how noisy the thrusters really were by
seeing how close he could sneak up on the diver.
        Very close.
        Hawkes ended up giving the diver a bear hug with the Wasp's arms. "He
went rigid, and then he went limp. At first, I thought I'd killed him, and
that might have been better. Now, I don't know about you, but when I turn my
head, it only goes about this far, but somehow, the diver got his all the way
around...."
        Then on the set of the Bond movie, For Your Eyes Only, that's Hawkes
in the Jim suit and the other submersibles again. They asked him to fly a
submersible up and over the camera for one shot. Hawkes didn't want to; the
camera was so valuable, only a few people were even allowed to touch it.
Hawkes was afraid of hitting it with the submersible. Somehow, they talked him
into it, and set the camera up on a tripod, with two big lights behind it, and
five divers in attendance.
        The submersible hit the camera square on.
        This knocked down several divers, and the wash and confusion brought
down the lights, and pinned down the rest of the divers. Hawkes was afraid of
what the thruster blades would do to all the arms and legs, so he killed the
throttle in the submersible.
        And gently set down on the pile of divers.
        He was concerned, of course, but by the time the divers fought the
battle for regulators, got themselves together, and looked in the dome, Hawkes
couldn't control his laughing. "They were pretty certain I'd done it on
purpose, but they asked me to do it again. So I did it again. The whole thing.
Now they were confused. I wouldn't do it on purpose twice, so we did it a
third time."
        This time, even though he blew ballast early, he was still heading for
disaster, praying the divers would scatter like sane people, and give him room
to maneuver. One finally broke ranks and fled. Hawkes dipped a wing, made it
through the gap, on to safety... and the diver stopped and turned around, and
got folded over the dome and carried on.
        I happened to be sitting with Ross Saxon, head of the Association of
Diving Contractors; he shook his head a lot. If I am ever in the water with a
great white and Graham Hawkes in the Wasp, I'd rather take my eyes off the
shark than Hawkes. On the other hand, I'd put up with a lot for a ride in one
of Hawkes' submersibles.

        Hawkes finally told us about the new stuff. He just built two new Deep
Rovers, the submersibles with the big bubble for a cabin (there's one in the
movie The Abyss), for a French filming company. They should have some new
films for us to watch soon. Hawkes said he hates when customers take away his
toys, so he's building one just for himself: Deep Flight. Here, I refer you to
Hard, for pictures and an interview. It looks like a stub-winged fighter jet,
and Hawkes says it should do about 12 knots, but right now, it's batteries
only last 7 minutes. It isn't quite done yet.
        The pilot lies down in the body of the short craft, and his head and
shoulders are entirely out in a clear bubble on the front of the plane. Hawkes
said that the clear material vanishes underwater; in Deep Rover, he reaches
out, and isn't sure when (or if) his finger will touch glass. "You wouldn't
believe it. You really should see it." Well, I'd like to, now that you mention
it.

        I did get to see a NewtSuit. The US company that contracts with Hard
Suits and is using the NewtSuit was there, with one of theirs in a rack.
They're right: it's smaller than you think outside, bigger than you think
inside. Like most of the tools there, it was being used for some unexpected
purposes: it was often being used to find and recover rare WWII aircraft for
museum restoration. Some of the pictures he had of rotten fuselages didn't
look like much, yet somehow, they could be turned into museum pieces worth
hiring a NewtSuit for.
        Another item that was seeing some unexpected usage was a software
package called Melian, from Webster Associates. Pretty simple stuff, actually:
you told the software about your sensors, sidescan sonar, magnetometers,
whatever, you told it how close to space tracks, how tight to make turns to
keep the sensors flying, you plugged the sensors and the autopilot into it,
and then you waited while it drove your boat and mapped the bottom for you.
They just developed it for some contracts they had, and it worked so well they
thought they'd see if anyone else liked it, so they came to tek. I liked it. I
just need a boat and some sensors, and I'll get it.
        Beuchat was there. I haven't seen their 190 cuft tank before. It
seemed a lot bigger than my OMS 120.
        Cochran was there, with their newest Nemesis. There were posts about
it earlier. It still looks good, the software interface keeps growing, it may
one day work with the Abyss software, and there is an upgrade plan for old
Nemeses.
        Force Fin was there. I said above that Nuytten's putting Force Fins on
the light NewtSuit. I mentioned this to Bob Evans, the inventor, and he got
all excited. He said he just thought of something a day or two ago that's even
better, hasn't even told Nuytten about it yet and couldn't tell me. Evans is a
mad scientist, and a lot of fun. He loves what he is doing, and his brain
won't stop churning out new ideas. However, he's gotten pretty tired of some
of the dive industry politics. He said that one big chain stopped selling his
fins and is telling people that somebody drowned in them. He said it made him
think about quitting. He was really excited and happy to be at tek with some
real divers. It was a lot of fun talking to him; his excitement was
contagious, and if I said something he liked, he'd get even more excited. He
had a pile of fins in the corner of his booth, all kinds of concepts, many
brands with skegs on them, all kinds of ideas. You'd start talking to him, and
he'd pull one out of the pile and have all the ideas embodied right there to
show you. I told him I noticed that each level of Force Fin had a certain
power band that it worked best in, and to prepare for emergencies or current
or lots of gear, I wanted a stiff fin, but was afraid it would be too
inefficient at low power. He was thrilled. He showed me the new fin, the stiff
one with the adjustable skegs. The most powerful, the fastest fin on the
market, he hoped. The skegs even adjust its power. Turn them out, and you can
cruise along. Turn them in above the blade until they are almost touching, and
when the fin flexes, a venturi forms in the pocket under the skegs. He was
getting more excited when I knew what a venturi was, that somebody understood
his stuff. I asked him if the cleats on the bottom were to make turbulent
flow, to keep it attached, and I thought he was going to bust. I asked him
about cave divers using his fin, since they can't scull or frog kick with
Force Fins, and he got excited again. His fin directs flow backward, not out,
so a normal kick, the most powerful kick, won't churn up silt. Cave divers
don't have to torture themselves with weird kicks anymore, and benefit more
than anybody from his fin.
        Bob Evans is lots of fun. I want to try his new fin out. I'll let you
know how it is. And if you see him at a conference, talk to him. He'll cheer
you up.

****************************************************

        OK, finally, the rebreathers. There were four at the show: two fully
closed, the Cis-Lunar and the Oceanic Phibian; two semi-closed, the Prism and
the BMD. The Phibian and the BMD were new to me, and I spent some time with
each of them.

        If you don't understand semi- and fully-closed, let's start there. If
you do, skip down. I know we've got some new subscribers who want to learn
about rebreathers, so here we go.
        Fully closed systems typically have two gases on board, pure oxygen,
and the diluent, which can be any gas: air, nitrox, trimix, heliox, pure neon,
whatever. An onboard computer fills the breathing loop with diluent and oxygen
to a life-sustaining level. By keeping the O2 level high, there is less inert
gas to load your tissues, so on the way down, your computer would be mixing
you nitrox. At the bottom, your computer will have you on a low O2 mix,
perhaps pure diluent, to keep O2 partial pressures below toxicity range. On
the way up, the computer will mix oxygen in as quickly as is safe, to speed
decompression, until near the surface, you are breathing pure oxygen.
        For bailout purposes, it would be nice if the diluent was something
with oxygen that could sustain you if your computer died and couldn't mix for
you any more.
        On the way down, the computer will be adding both gases, to keep the
loop full. On the bottom, the computer will be adding only oxygen, since the
only gas lost is metabolized oxygen. Oxygen is metabolized and CO2 is produced
at the same rate, regardless of depth. So little gas is used overall that
fully closed systems are typically limited in duration not by gas supplies,
but by the amount of CO2 that the chemical scrubber can remove from the loop.
        On the way up, the loop will be overpressurized and vent gas. Divers
with bad buoyancy control will waste gas, and may find themselves limited by
gas supplies.
        Semi-closed systems have only one gas on board. It had better be
breathable. As you breathe and gas flows around the loop, oxygen is lost, but
rather than add pure O2 to replace it, gas is added. Let's say the gas is
EAN50, to keep the math simple. If you've consumed a liter of oxygen, you need
a liter of oxygen. To get it, you have to add two liters of EAN50, by dumping
an additional liter of gas from the loop. Semi closed systems actually achieve
this by keeping a steady flow at a *critically* measured rate into the loop.
Semi-closed systems are actually constantly bubbling, although more quietly
than scuba. They are typically limited in duration by gas supplies, but you
might be able to simply bring more. Some manufacturers argue that since divers
rarely stay at one level, semi-closed is as efficient as closed, since both
systems will be constantly dumping gas on a sawtooth profile. Semi closed
systems are simpler, and do not need to be computer controlled. I'm making
some sweeping statements here, oversimplifying a lot, but this should be
enough to get you through the rest of the post. I know there are exceptions.
Ask me questions or flame me as you choose. If you want more, I'll help, but
the first thing I'd recommend is getting an aquaCorps back issue, C2.

        The Cis-Lunar was well described in Steve Millard's recent post, so
I'll be brief on it. It is everything you've heard, maybe everything you want.
It has the look of a really well built, really durable, really efficient tool.
This unit in particular had the marks of standing up well to some really heavy
use. This was not a concept mock-up. This thing works. The Mark IV is not that
streamlined; the new Mark V should be better.
        The Oceanic Phibian was there in concept form. It should be out later
this year. There are two models, and a few options, so pricing is uncertain,
but my guess is it starts higher than the semi-closed, uncomputerized units,
and lower than the Cis-Lunar. If you buy the redundancy for the Phibian that
the Cis-Lunar has, it may cost as much.
        Like the Cis-Lunar, the Phibian is fully computerized and will keep
you at a high PO2 to speed decompression. The rebreather, including the
breathing bag and 2 or 4 small cylinders, is entirely housed in a hard shell
that slips into what is basically a large pocket on the back of a BC. The
whole package is about as streamlined as a rebreather can get. This is the
rebreather with the most inside the case; all four have some kind of BC
bladder outside, and the other 3 have their breathing bags outside. The
breathing bag inside on the Phibian may be a little high, and since it will be
displacing water inside a case, it might be a little hard to breathe on. It
will be interesting to see. The Phibian was not going to be available in the
pool sessions, and I couldn't stay anyway.
        The base Phibian comes with one computer, which hides under the stack
in the shell, and one display, a solid case with a large LCD display. The
displays looked good, clear and complete. The computer listens to 3 oxygen
sensors; a CO2 sensor can be added. The 4 cylinder model can handle mix. The
cylinders are mounted inverted, with valves and purge controls on the bottom,
where the user can easily reach them. Flooding is recovered from by hitting a
purge and overpressuring the loop; there is a vent on the bottom of the stack,
the lowest point in the system, to vent water. Duration, as in most fully
closed systems, is limited by the absorbent, and should be 4-6 hours at any
depth.

        The BMD and the Prism are semi-closed systems. However, there are
several differences between the two. The Prism is a very simple system, and
the least expensive. It consists of a breathing bag, a canister of absorbent,
and enough plumbing to get air to your mouth. You attach the system to your
own BC and cylinder; the canister rides on back next to your tank, and the
breathing bag goes on your chest. The canister looks large and not
streamlined, something like 8 inches across and perhaps a foot high, like the
lower half of a scuba tank. 
        The BMD unit comes with its own cylinders and vest; the stack,
cylinders, and plumbing fit into a shell which rides on back of the vest. I
was very impressed by the BMD's breathing bags: there are two of them, toroids
around each arm inside the vest. With this layout, whatever the diver's
orientation, there should be a breathing bag available at lung level for easy
breathing. There are four small cylinders inside the backpack; I was surprised
to see that they were composite and perhaps high pressure. I can't get fills
at pressures high enough to justify composites, and they probably add expense.
The BMD also had an Orca Phoenix attached; I'm not sure how it handles mixes
other than air.
        The biggest difference between the two is the flow control used to add
gas to the loop. The Prism uses a mass-flow valve, basically setting a flow
rate. The BMD, as I understand it, uses another kind of valve that simply
dumps 25% of each exhaled breath overboard and out through a nice diffuser to
keep things quiet.
        You know, if all you fish guys want is silence, that's not hard.
        Anyway, by my math, the BMD unit very simply stretches air consumption
by 4 times. The Prism's consumption rate is based on flow, but is probably
similar.  The Prism's flow rate is adjustable; it didn't sound like the BMD
is. Here's an interesting note on semi closed: you are actually breathing a
lower PO2 than what is in your cylinder, if you think about it. The BMD people
had worked out the math, and were quick to tell me that if you use air in
their system, you are actually getting EAN17. Nice to know. Since a lower
percentage of O2 is consumed at depth, I bet the O2 level is higher at depth,
and lower near the surface, kind of opposite what you want. Perhaps not
significant, but this is a forum where we split hairs.
        Anyway, one final note, and I'll wrap this up. I've heard that more
than one Prism rep based his sales pitch on what's wrong with the Cis-Lunar:
it's sooo high maintenance, so expensive, uses just as much gas on sawtooth
profiles, blah blah blah. Well, at his booth, Peter Readey, the Prism's
inventor, gave me the same negative sales pitch. This attitude starts at the
top. I hope somehow he reads this. It really turned me off. I like the
Cis-Lunar.
I like the Prism. I like all the rebreathers. They are all different. I wanted
to hear what was right with the Prism. There is a lot right with the Prism. It
will probably sell more than the others, based on price alone. I wish Readey
had answered my question instead of jumping on the competition. He's built
rebreathers before, including fully closed, and he knew exactly what he was
doing when he made the Prism. He had a world of options when he built it, so
he I know he knows all it's good points. I wish he'd told them to me.

        I hate to end on that note, but I've finally run out of things to say.
 This show was so worthwhile that I plan on making the long trip to New
Orleans next year. I did my best at the show to try to get a job in the
industry so I'd have an excuse to. I hope other people, and the industry, got
as much out of it as I did. I'd really like to thank Michael Menduno and
everyone at aquaCorps for calling everyone to this party, and then working so
hard throughout it.


#----------------------------------------------------#
 Roger Carlson                        H 310-frogger
 Somewhere off Hermosa Beach, CA      W 310-813-0858
 Roger_Carlson@at*.sp*.tr*.co*      F 310-812-1363
#----------------------------------------------------#

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