Report on first deep hydrogen dive using a rebreather
- Thread starter Dr Simon Mitchell
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Congrats to Dr Harris and Dr Challen on this achievement! I am sorry to hear about the DCS cases that were experienced and I hope they have a speedy recovery. It looks like this may be a pause or stop in the hydrogen work by the Wetmules.
Blackwater Hunter
Registered
Legit my worst fear with hydrogen mix. Imagine the end of Jaws, except it's you. If it was EVER me in the future, everyone has my permission to talk about the whole dang thing. Blast radius and all.
Scuba Boys And Hydrogen
Imagine this but about 100 times bigger. Not even Richard Harris could resist
Learner Diver
Contributor
Can anyone fill hydrogen into your cylinders, or do you need to be trained?
This is experimental so no, this is not something that training even exists for. It would be difficult to get compressed hydrogen and even if you could it is extremely reactive. Check out the above YouTube link for the team that was conducting these experiments throwing a bag with a few liters of hydrogen into a fire.
Learner Diver
Contributor
Anyone can make hydrogen. Purifying it is another story.
This person dives almost 100% of the time on H2 mix in his home country of Macedonia. He is a very active diver and a friendly person.
I met him on a dive trip in Hurghada this past February. For those of you that want more information, you can follow him on FB, ljubomir.gligorov
www.facebook.com/ljubomir.gligorov
I met him on a dive trip in Hurghada this past February. For those of you that want more information, you can follow him on FB, ljubomir.gligorov
www.facebook.com/ljubomir.gligorov
Blackwater Hunter
Registered
Hydrogen cylinders are also finicky so you have to make an adapter to fit it to a DIN valve, then you can pump it into a normal gas cylinder. Now the problem is transport, because I bet all SCUBA gas cylinders are not rated for compressed hydrogen gas (even though they handle it pretty well). This is less a safety concern and more of a legality concern. The best way to use it would be how they did it. Mix the gas in the loop, exactly like how the oxygen is mixed. OC is probably out of the question because of liability concerns and it's not economical to tech dive OC with any gas. The deco tanks alone would be outrageously expensive
Bounce tech dives don't even have an optimal decompression method, which is probably why everyone got bent. Right now the protocol is essentially bounce from habitat to habitat at different depths at set increments of time for each one. Easy peasy, except nearly all of them got bent on this occasion. I wonder if something accelerated the saturation rate, or just slowed the decompression. Aside from temperature and hydration.
OP
Hello,
Unfortunately, I was not able to participate in the expedition to Boesmansgat because of a prior commitment to another diving expedition. So, I was not there.
Just to clarify a couple of points.
Harry and another diver suffered DCS. Only Harry was using hydrogen.
Harry's event occurred after an uneventful dive to >280m several days before. On this dive the use of hydrogen once again appeared to successfully ameliorate HPNS symptoms as we reported from the first dive at the Pearse.
The incident dive did use hydrogen, but I don't think we can confidently link Harry's DCS to the use of hydrogen (we can't rule it out either). Bounce diving to these sorts of depths is associated with a high risk of DCS no matter what gas you use. For prospective explorers thinking of going deep it is worth bearing this in mind. Virtually everyone who has bounced dived beyond 250m has been injured at some point if they choose to admit it. Moreover, the added complication at Boesmansgat (often overlooked) is that it is at 1500m altitude. This adds a significant complication to extreme-depth dive planning that may not be reliably mitigated with the use of the simple altitude corrections used is planning of more normal dives.
It was suggested above that commercial divers use hydrogen all the time. This is not true. To my knowledge no one is using hydrogen in commercial diving. COMEX experimented with it extensively for a while, but it never became mainstreamed.
Simon M
Unfortunately, I was not able to participate in the expedition to Boesmansgat because of a prior commitment to another diving expedition. So, I was not there.
Just to clarify a couple of points.
Harry and another diver suffered DCS. Only Harry was using hydrogen.
Harry's event occurred after an uneventful dive to >280m several days before. On this dive the use of hydrogen once again appeared to successfully ameliorate HPNS symptoms as we reported from the first dive at the Pearse.
The incident dive did use hydrogen, but I don't think we can confidently link Harry's DCS to the use of hydrogen (we can't rule it out either). Bounce diving to these sorts of depths is associated with a high risk of DCS no matter what gas you use. For prospective explorers thinking of going deep it is worth bearing this in mind. Virtually everyone who has bounced dived beyond 250m has been injured at some point if they choose to admit it. Moreover, the added complication at Boesmansgat (often overlooked) is that it is at 1500m altitude. This adds a significant complication to extreme-depth dive planning that may not be reliably mitigated with the use of the simple altitude corrections used is planning of more normal dives.
It was suggested above that commercial divers use hydrogen all the time. This is not true. To my knowledge no one is using hydrogen in commercial diving. COMEX experimented with it extensively for a while, but it never became mainstreamed.
Simon M
justinthedeeps
Contributor
Does anyone know the ascent rates and GFs for their ascent? Were they exactly the same as all prior asymptomatic dives?
Do gradients change more quickly with changes in depth for a super lite gas? Does this require slower ascent rates, deeper habitats, and/or special procedures/maneuvers to assure perfusive off-gassing?
How does the tissue solubility compare for H, He, and N2?
Is it possible to:
a) predict the number of these gas molecules that will enter and leave the body during the dive, and
b) employ any device sensitive enough to measure (a) happening in real time?
Maybe that was part of the hope with the Liberty helium sensor?
Do gradients change more quickly with changes in depth for a super lite gas? Does this require slower ascent rates, deeper habitats, and/or special procedures/maneuvers to assure perfusive off-gassing?
How does the tissue solubility compare for H, He, and N2?
Is it possible to:
a) predict the number of these gas molecules that will enter and leave the body during the dive, and
b) employ any device sensitive enough to measure (a) happening in real time?
Maybe that was part of the hope with the Liberty helium sensor?
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