DIR- GUE Why are non-GUE divers so interested in what GUE does?
- Thread starter crofrog
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flymolo
Contributor
I don’t think that’s what it’s designed for. In fact I’d argue it’s better suited to boat diving than cave diving. There aren’t many too many people in north Florida who dive that configuration in caves because the BO radius with just the 50s alone means you need to drag a full stage bottle around with you most of the time.
I believe the main design philosophy of that rig is that you carry a lot of bailout already on your back in a set of redundant tanks.
The "backgas" isn’t redundant as they’re also consumed as your diluent. A week's boat diving would need a couple of gas top offs or need different backgas cylinders for different depths. For any dive beyond recreational depths you still require deco bailout(s).
A normal** rebreather — such as a standard JJ — doesn’t consume gas from the bailouts (aside from powering up the regulator and test breaths). The standard three litre dil and oxygen cylinders are smaller, cheaper and far easier to manage — than the TWO 7 litre cylinders with special valves on the GUE JJ. Diluent PPO2 is normally different (~1.0) from your bailout PPO2 (~1.4), so your "dilout" would compromise your bailout, probably being hypoxic for moderate depths (60m/200ft) and beyond.
Normal rebreathers are lighter and smaller thus easier to move around and stow. This is particularly important when carrying kit to a site where breaking it into smaller units may be essential.
The longhose means that you cannot pass over your bottom bailout to a person in need. You will be permanently tied to them whilst they’re consuming your diluent. An OOG donation is more or less the same on a normal rebreather— you pull out your bailout regulator and shove it in their face. Then you unclip your bailout and hand it over to them so they are independent from you.
Lots of compromises seemingly for little or no benefit.
Have often wondered why normal rebreathers have standardised around the JJ style configuration of a pair of 3 litre cylinders for diluent and oxygen, a large 2 litre suit inflate cylinder and fully redundant bailout cylinder(s). The GUE format JJ stands alone in its design that no other rebreather manufacturers have adopted.
** For this discussion "normal rebreathers" do not include sidemount nor chestmount formats.
Permanently attached to them. So cannot handle other issues without your Siamese twin.
A longhose bailout will be way more stressful for both people than a standalone bailout breathing from a stage cylinder. Any buoyancy fart affects both divers, any computer distraction, OOG diver needs to hold on to the hose, etc.
Agreed it’s exceedingly rare that a diver loses both bailout and their CCR. Has it ever happened?
I see the issue as no different than dealing with an OC diver that is out of gas. Personally, I want to be there with them controlling the situation.
Regarding a CCR diver going through all of their bailout, I know of two incidents and I was in a third bailout issue where I had to help manage the situation. All three involved CO2 hits, one of the incidents I was told that the diver went through 8 bailout bottles (AL80s) between 210'/65m and 70'/21m before his breathing got under control - yes, over 600 cubic feet of gas. The second incident involved 3 CCR divers where one had to bailout coming up from 100m and they went through all 5 bailout bottles that were split among the team. The third incident (I was involved with this one) was a guy who took a CO2 hit coming up from 300'/90m and myself and four other people had to help him with his bottle swaps and deco until around 50'/15m when he finally came through enough to get back in control of himself.
The first and third incident involved divers that were pushing a used scrubber well beyond it's limit.
beester
Contributor
Trick question! We all know that bailout gas volumes limit bottom time way more than a rebreather's limits.
If a CO2 hit is considered then you'd be lucky to get out of that dive alive and will definitely -- as per @kensuf's post above -- require additional gas.
If discounting a CO2 hit, which is a strategy for some, then your bailout for 75m for 40 mins will be more than 2 ali 80s, probably including an intermediate/travel gas. Also pre-planning drop tanks.
What's the view of bailout with CCR2/T2/T2+ rules? Team bailout?
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