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David Drake writes:
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Now THE tech dive shop spouts religious experiences regarding Odins. On the bad
side, I've had two different buds, one a caver and the other a commercial
diver, have very negative religious experiences. At about 120-130 ft. and 38
degrees F, their Odins started sending ice chunks into the back of their
throats! One had an environmental kit, one did not. After talking with other
Lakes tech divers, they admit to the same happening to them. The problem is
the diver's breath freezing in the second stage. Something about the design
of the Odin deficient in regards to cold/deep water.
I've seen too many holes in the fragile rubber environmental caps on the Odin
1st stage. I'm totally disillusioned with the "every diving god in Florida
uses these 'cause they're the best" sales pitch. For my diving they kill. I
understand they had recall after much trouble too...
... comercially-self-severing shop technician, who has screwed up servicing my
equipment twice too often for my pursuit of happiness.
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I too was pursuaded by the pictures of techie divers with Poseidon Odins, or
Jetstreams as they are called in the UK. I bought my first in 1992, and on the
first dive it had a nasty reverberation on inhalation. After wading through
lots of bulls..t from the dive shop, I decided to send it back to the importers
UWI. Something was myteriously done, and the problem went away. I could not
get an adequate explanation, other than the interstage pressure was 2 bar down.
The valve performed so well after this, that I bought a second. This had the
same reverberation problem. Faced with more unimformed "advice", and more
hassle, I decided to strip the second stages down and swop parts to isolate
the problem. The culprit was the silicon bladder which forms the main valve
of the unit. I 'phoned UWI, who then investigated, and found a problem with
their production methods. A new bladder was supplied, and the problem
dissappeared. Both valves now function perfectly.
Two points arise from this:
1 Both valves were down on interstage pressure when sold. This is apparently
due to soft components settling in after assembly. The dive shops should
correct this, but don't.
2 UWI said that they are now issuing or fitting, on request, new bladders
to anyone who experiences reverberation problems.
As for the ice, I too get chunks flying into the back of my throat, which make
me choke. It only seems to occur in fresh water, below 4 degC. The Jetstream
2nd stage is a wet one, as water leaks in thro the exhaust valve on exhalation.
This has to be expelled frequently, by tilting the head down whilst breathing
out. Also your breath condenses on the metal components inside. All this
water freezes to the innards, and breaks off every now and then.
I have never had a Jetstream freeze open during a dive. I did deliberately
try it to see what it was like. It took over a minute of purging in 4 degC
(1500+ litres/min!) to set it off. Once free flowing, the valve was impossible
to breath from, as the flow rate was too high. At this flow rate, you can
forget about trying to get your tank turned off as a full 15 litre cylinder
empties in about 2 minutes.
Both my 1st stages have the rubber cap, filled with glycerin solution. They
are vulnerable, so I have them facing down towards the cylinder out of
harm's way.
All in all, these valves are definitely an aquired taste, but once mastered,
they do breath noticeably easier than many others, especially at depths
beyond 40m.
Bill Dyer
Nuneaton SAC (SAA #220)
Warwickshire, UK.
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