Robert H. Diver
Contributor
So they are not switching gases in SSI Decompression Diver course and the bottle is for redundancy with the same mix as the back gas?
It says they teach gas switching, but doesn’t say how high your O2% can be.
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So they are not switching gases in SSI Decompression Diver course and the bottle is for redundancy with the same mix as the back gas?
Standards say that the dive must be planned so that the entire dive can be done on the back gas. Switching to a slung pony for deco with up to 40% Nitrox is allowed. Long hose is encouraged but not mandated. A good instructor will help students see the wisdom/convenience of a long hose. Backplate & wing vs. jacket with a single cylinder, I have my own preference, but nothing wrong with a limited amount of planned deco using a jacket BCD - it's not the BCD that's going to kill you.It says they teach gas switching, but doesn’t say how high your O2% can be.
Basic nitrox is a prerequisite, so 40% max.It says they teach gas switching, but doesn’t say how high your O2% can be.
Standards say that the dive must be planned so that the entire dive can be done on the back gas. Switching to a slung pony for deco with up to 40% Nitrox is allowed. Long hose is encouraged but not mandated. A good instructor will help students see the wisdom/convenience of a long hose. Backplate & wing vs. jacket with a single cylinder, I have my own preference, but nothing wrong with a limited amount of planned deco using a jacket BCD - it's not the BCD that's going to kill you.
There is no requirement for split fins or snorkel
Basic nitrox is a prerequisite, so 40% max.
Standards say that the dive must be planned so that the entire dive can be done on the back gas. Switching to a slung pony for deco with up to 40% Nitrox is allowed. Long hose is encouraged but not mandated. A good instructor will help students see the wisdom/convenience of a long hose. Backplate & wing vs. jacket with a single cylinder, I have my own preference, but nothing wrong with a limited amount of planned deco using a jacket BCD - it's not the BCD that's going to kill you.
There is no requirement for split fins or snorkel
Remember that this is a RECREATIONAL course and so it teaches that an OOG diver would do exactly the same as he would do in a recreational OOG situation and share air with a buddy. Gas planning for this dive accounts for sufficient reserve to bring yourself and an OOG buddy up to the deco stop where there is plenty of gas available (remaining back gas & 2 deco bottles). I am not disagreeing that ascent to deco would be MUCH better with a long hose and, as I said, this is encouraged but is not mandated.All of it raises a lot of questions. Imagine that you are diving to a depth of 130 feet (which is the max depth for this course) and you have a failed valve. If you were in twin tanks, you would shut down the valve and switch to the other tank but here you can not do that because you just have one! You could have switched to your bottle, but that does not have your back gas for that depth but a nitrox mix. so you are below your MOD to make that switch without killing yourself.
Do you hold your breath and swim to the gas switch depth?
It is not the BC, or the backplate that is doing the killing, it is lack of skill, and in this regard BC or Backplate makes little difference. You can't rely on equipment to substitute for poor skills, and you can't bolt a backplate onto an unskilled diver and expect that the diver will suddenly acquire skill. I dive a backplate, always have since my first dive after certification. I believe it is a superior system, but let's not drink so much of that Kool-Aid that we think that it is the only system out there for single tank diving.Can the jacket style BCD kill you? Yes of course and that is the reason why it is not in popular use when it comes to tech diving
Here in Europe, Cmas, Bsac, Fipsas and other organizations always had fully recreational certifications including deco procedures.Sorry but I am a bit confused and may not be understanding this correctly. If someone, who has taken this specialty or teaching this, could give a little more information and address my curiosity, Id be grateful.
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Going into decompression requires proficiency in backplate and wing with long hose and that is what our TDI's Intro to Tech does, or GUE Fundies or UTD Essentials. I believe SSI has its own variant called XR Foundations. Apparently, these are not required for SSI Decompression Diver. Am I correct to understand that this takes you outside of recreational diving into technical diving parameters WITHOUT the training and the gear configuration of tech? A tech course in a BCD jacket with split fins and snorkel??? A lot of questions come to mind.
Is the single tank required to have an H-valve? How would you shut down the compromised valve if that is the only one you have?
How do you manage air share without long hose? Recreational hose lengths are good if you are taking the fellow straight up to the surface but if you have a deco ceiling above you, then it needs to look something like ...
View attachment 773910
instead of ....
View attachment 773911
So can anyone please shed some light on what exactly is SSI's "Decompression Diver" specialty???
???All of it raises a lot of questions. Imagine that you are diving to a depth of 130 feet (which is the max depth for this course) and you have a failed valve. If you were in twin tanks, you would shut down the valve and switch to the other tank but here you can not do that because you just have one! You could have switched to your bottle, but that does not have your back gas for that depth but a nitrox mix. so you are below your MOD to make that switch without killing yourself.
Do you hold your breath and swim to the gas switch depth?
How exactly does this course teach you to address that particular scenario, which is repeatedly drilled over and over again in an Intro to Tech? You could ask your buddy for air share, but that fellow is in recreational configuration, which is optimized to take an out of air diver all the way up to the surface. Not a good thing if you both have accumulated decompression obligation which is the sole purpose of this course. Tech divers are trained to do horizontal ascents to the gas switch depth and long hose also enables them to do a stop while air-sharing. Not here.
I am not saying that SSI does not have any solutions to those. If it does start to acknowledge those scenarios, then the course would look exactly like TDI Intro to Tech. Can the jacket style BCD kill you? Yes of course and that is the reason why it is not in popular use when it comes to tech diving. Holding a 20 ft stop, or a stop at any other depth, perfectly still in horizontal trim, without depth fluctuations is a skill that entry level tech divers always struggle with. It is like tight rope walking, where if you inhale just a tad too much, you go up and you exhale a tad too much you sink. Now do a gas switch while holding that depth with precision and it is no longer easy. Most people will be all over the place when they are even slightly task loaded.
As you throw situations such as valve shutdown, deco bottle passing or air share, then holding that depth with zeroed in precision becomes even more difficult depending on the nature of the task. And keep in mind that these are divers who are ideally configured to hold that stop, while being task loaded and they have been repeatedly drilling such things with hours and hours of repetitions.
Anyone who says that they can take a recreational diver, and make them do all of that in a jacket is not being honest to their own self here. But once again, I may be talking totally in the air because I do not know what they are teaching in that course. Still don't. The described parameters of that course raise a lot of questions.