Reaction on Deep Rebreather Dive - RB Bailout Concept discussed

[@CoastalDevelopment]

Clarification: - No this has nothing to do with the latest Divetalk reaction that RB Bailout. (Neither 90 meters not overhead) - i state a couple of times during ghe Video that the numbers used are FOR ME and stabd as an example to explain the thinking behind. You can use and calculate with whatever RMV you want to plan and deco 1000 minutes or not at all. - it helps if you wantch the video before you comment on it ;-)

[@mirodebikki4413]

Thx Achim for youtube vid on this important case. I have digested original one which was brave to be shared... Personally I dive on Tiburon and concept of critical BO is almost the same as your approach. Those of us who dive on CCR and understand total failure of the system at deep depth shall study this case coz there is enough to be learned from. Saving lives by speaking out is a courageous way. Full respect goes to you Sir ;)

[@pork-techpty3078]

Thanks for the video, I couldn’t work out your planned RMV, I think it was 15 lpm for the full bailout, I would have thought that this is a low breathing rate in the event of a CO2/hypercapnia issue particularly for the initial stage of the bailout?

[@beluil]

Think there was a case of a guy diving ccr on air in ressel with two BO 11l full of air. Ccr malfunction lead to bailout and panic attack. 120l/min was his breathing rate. Dead obviously as he had 500m of swim at 50m and another 300m at 10-20m. Never heard of anyone dying of having too much gas though. If you're not comfortable with carrying enough gas to bailout, perhaps shouldn't dive as deep or far.

[@lp4200]

I would assume min 40l per min for bottom part in case of hypercapnia for whole 15min . You can place 2 stages at the line as deposit. If q-ty of stages is an issue the take scooters. 90m @ cave @ 30min is serious dive

[@DavidMaruca_]

Thanks for sharing. Open water wreck penetration, and cave diving, have very interesting innate logistical challenges. It’s very entertaining listening to you discuss your priorities and decision making 👍 See you on the next one!

[@CubanazoJB]

Great video buddy!!! Lots of knowledge as always!!

[@sidemountpros]

Nice Achim, thanks for sharing.

[@peterjulianphotos4659]

I watched the original video and have seen some other commentary on it. I'm not a rebreather but I've been diving for 40 years, and could snorkel before I could ride a bike.The diver had problems with his rebreather pretty much from the start of the dive, he knows that he was using his dil at a crazy rate but continued with the dive. IF it's the same video he was coming from 68 metres and he also had a surface supplied 100% O2 for his final deco. I think he probably should have called the dive when he initially hit the wreck and knew he had "a problem" without knowing what the actual problem was, but hindsight is 20/20 as they say.

[@trevorduncan9635]

Fantastic video. Most appreciated.

[@louis840]

Great content ❤

[@briangates8428]

Really like your videos and your way of thinking. I also prefer to carry every stage I might need, at all times in environments where it is possible that I could be separated from staged cylinders even when it’s improbable. Perfect example is deep wreck penetration: some divers I know on the dive described would be comfortable securing their 21/35, 50, and 100 to the outside of the wreck for ease of travel while interior…but the “what-ifs” of that make me uncomfortable. What if I’m forced to exit at an unplanned location; what if the line the stages are clipped to is severed, what if the wreck rolls and pins the stages? Sure each scenario is very unlikely, but isn’t the whole point to plan for worst case. I’d much rather do a blue water ascent adrift with all my gas, than ever realize a cylinder I need is no longer available to me cause I placed it somewhere that is now unreachable. So if that means some parts of the wreck are inaccessible to me, so be it. Better than the alternative in my opinion.

[@harambeexpress]

Makes sense to me.

[@dassdar]

From my perspective it's imperative to have the easiest to use setup in an emergency. Adrenaline is a hell of a drug! And bailing out on a rebreather is probably not a low task load under stress. I also agree that you should not do dives, when you cannot implement the proper safety concept. And "feeling safe" is not being safe. That is where safety becomes a matter of discipline and logical reasoning. Smokers don't feel unsafe, but they mostly know that what they do is not safe from a logical perspective and they still do it. And peer pressure and the slow and steady shifting of boundaries is what usually leads to smoking. I would think that this is the same with diving in a less safe manner. Sharing bailout is the norm for reacreational OC, OW dives and I think for many recreational divers it is an absolute hazard. It requires practice and discipline and good decision making before the incident. During my vacation I saw dive buddies 30m apart, not watching each other at all. They were basically solo diving. No discipline at all. But in such a case, would giving them a bailout stage help? Or would that just lead to them breathing down the stage as well to get more bottom time? Also your units are not correct in the formula written in black marker: RMV should be in l/min, the "10 bar" should be "10" without unit (you compress air from 1bar to 10 bar, so it's a compression ratio: 10bar/1bar=10). And for people who just learn this, it is important to get the units correct. Because if your units don't add up, you may have made a mistake in the calculation.

[@CoastalDevelopment]

Thanks. I don't know what you refer to withthe wrong units / formula. 90 meters give a pressure of 10 bar, 15l /min rmv for 15 min are the other 2 numbers you need to do the math. That's what is also written on the board 🤔.

[@dassdar]

Hi @@CoastalDevelopment :) Thanks for reading my long comment! Yours: 10bar * 15l *15 min = 2250l (Units on the left: bar*l*min) Mine: 10*15l/min*15min =2250l (Units on the left: l/min*min=l). In your response now you wrote 15l/min rmv. On the blackboard you wrote 15l (I know this was just a typo). Regarding the pressure: it is correct that there is 10 bar pressure at 90m. But there is also 1 bar at 0m. So you need to take the compression ratio 10bar/1bar=10 to calculate the volume that the air would have at the surface. It is also explained well in this video: kzbin.info/www/bejne/aH6ldGWbhMuXjsUsi=6qXF47ffW72E9eQ_&t=62 Have a nice rest of the weekend Niko

[@THDAus]

It’s not very obvious from the whiteboard, have you assumed that they do a 30 minute bottom time then do a 15 minute swim out then have 150 mins of deco? If they bailout at the worst point (from an OC gas consumption perspective), they’ll have only done 15 mins of bottom time (although they will be forced to do another 15mins on the way out). In principle, I’m not convinced that every diver should always carry all their own bailout. In open water with currents/bad vis then having all your own gas makes sense but in an overhead environment or open water with no current and exceptional vis, team bailout is probably a lot simpler to handle as you are extremely unlikely to get separated (I am a big advocate of team diving regardless). Having said that, both divers would need to carry a bottom bailout which means that they are limited in the choice of deco gases meaning that 4 tanks between them doesn’t sound like much to do an optimum bailout ascent…. It would be useful to read about the story you’ve referred to in order to allow us to better consider their choices. Context is everything.

[@CoastalDevelopment]

Did you watch the video?

[@THDAus]

⁠​⁠@@CoastalDevelopment yes. I just watched it again to double check and see if I’d misinterpreted anything. While the narrator does state he is catering for 15 min penetration, then 15 mins out then an ascent, the white board wording doesn’t make that clear to me and I just wanted to clarify.

[@benzmansl65amg]

I agree. Team bailout is insane imo. Every member of the team needs to carry their own bailout.

[@thorstenklein3719]

I´m really with you, but 15l/min is quiet low for a emergency planning. I guess I know what video you´re talking about. They had Backmount CCR´s, why not using a chestmounted BO-CCR? with a off board S 80 of Bottom mix, like my Triton.

[@benjaminbeier4036]

I am not a TEC diver yet (only have a S.U.B fundamentals), but I am not sure I would feel equally safe using a BO-CCR compared to having sufficient OC bailout gas. The BO-CCR is still a complex machine with plenty of parts that could fail. With OC bailout I not only have a ton of gas with me, but also a whole collection of regulators to swap around if one fails. Just my thoughts without having any practical experience with TEC or Rebreather diving. But I guess double Rebreather with a limited amount of OC bailout gas can make sense if you have a whole support team around, so you only need to make it back to some habitat or whatever. I know that Richard Harris and his buddy dive a Twin Megalodon backmount setup pushing beyond 200 meter depth in caves, but I have no clue what their gas planning really looks like.

[@thorstenklein3719]

@@benjaminbeier4036 Yes, there are risks like all activities in that range, but loosing a BO gas is also possible and before I would use more that 3 or max 4 tanks it´s way more compfy with a BO CCR. Due complexity - yes there are some more procedures, but you will get used about.

[@saschaganser9671]

Is this a reaction to the 68m CCR bailout video? I guess not. But as far as i understand, he kinda ran out of bailout and needed tanks dropped. A lot is to learn form that video, especially how long it can take to realize you have a problem. Many open circuit diver violate the rule of having enough gas at the deepest point of the dive for their buddy team. Just think about, how many divers are at 30 or 40m with about 120 bar in their 11l alu tank. If you calculate gas loss, a couple of mins to figure out there`s a problem, 4-5 mins to surface and higher sack rate, it will already be tight. I like your approach to dive planing, but in reality it would make a lot of dives impossible. Some penetrations won`t happen with 5 cylinders, and i understand the argument that there`s not much sense in taking gas down to depths you can`t breath it if you can store it safely.

[@D33pUK]

Hi Achim, an interesting and thought provoking video so thanks very much for putting it together! I also very much support your view that individual divers/teams need to determine bailout strategy based on their particular circumstances and approach to risk I've recently posted a video of a 90m wreck penetration by two divers with twin Ali-80 as bailouts - kzbin.info/www/bejne/Z4OmgZh5nqemmck so thought it might be useful to discuss our strategy! We *only* (!) did about 10 mins of penetration so not quite as challenging as your example. Each diver carried an Ali-80 of deep bailout (mine was 13/70), one diver had an Ali-80 of 18/46 and one diver had an Ali-80 of 50%. So in total four cylinders Diver 1 - 13/70 and 18/46 Diver 2 - 13/70 and 50% Our plan was based on a more pessimistic RMV than yours but we calculated that each individual diver's deep bailout provide 10 mins of gas to get them out of the wreck. Once out of the wreck we could then use the deep bailout carried by the second diver (if required), or ascend to a suitable depth (~60m) to switch to the travel gas (18/46). Obviously the 50% would then be used at 21 m. Like you, we assessed that this wasn't adequate gas to get the diver out of the water so the boat had additional cylinders that ccould be deployed down a DSMB to allow the diver to complete their decompression. This procedure is very commonly used by UK/Irish divers so both our surface teams and divers are proficient in the technique. I expect you've seen my loop flood bailout where this procedure works well - kzbin.info/www/bejne/eIDRpHVsgLmlpqc As an aside, I wouldn't dream of trying to swim around a wreck in UK conditions carrying 5 cylinders 🤣 Hope that was useful

[@CoastalDevelopment]

Thank you Dominic, very much appreciated - cu soon

[@Skunkiboi]

Disable the ai translation voice...please. Its terrible. Is not possible to turn it off on our side.

[@CoastalDevelopment]

@@Skunkiboi it is a user feature, you can turn it off .