Alternative to doubles

[gsk3]

...and if you have to share with a buddy who's lost their deco gas?
..and if you have to share with a buddy who's lost their back gas?
Exactly

As I'm sure you know, deco gas loss is different than back gas loss because you still have something to breath while the other person is borrowing your bottle

 

[Wookie]

Who says we forget that? I can explain every every failure point and benefit of every rig I dive, sometimes better than someone diving a conventional rig who just "trusts" it will work out because that's what they were told to use. Please don't put words in someone else's mouth.

If you read it again, I said that sidemount divers and Independant doubles divers tend to forget gas planning for failure, not always forget gas planning for failure. Take a pill. What I see about sidemount divers is that they dive that way for conveniences other than gas planning and redundancy. That's fine for no mount or sidemount restrictions in wrecks and caves. It's just another tool in the toolbox. I see more and more sidemount divers diving sidemount because it's cool, or easier on the body. That's great for single tank numpty dives, but when the depth gets deeper than is safe on single tank, or the situation gets more complicated than can be safely planned for more than a single failure, it makes more sense to dive manifolded doubles. Redundancy is king.

 

[DevonDiver]

As I'm sure you know, deco gas loss is different than back gas loss because you still have something to breath while the other person is borrowing your bottle

Yep, that's why I asked both questions

If deco gas was lost, then there might not be sufficient to share and complete planned deco. One diver could use backgas, but that could extend a deco schedule beyond the supply.

It can all be planned for, but using the OP's suggested configuration is going to make that a confusing solution, and add a lot of stress/pressure, in an otherwise straightforward and easily rectifiable scenario. How much gas do I/we have remaining? In what cylinders? What mixes? What's my SAC? What's my buddies SAC? How does that compute? Who needs what cylinder? Do we split to complete now varied deco schedules? Do I hand-off a cylinder? Which cylinder? etc etc etc

If you read it again, I said that sidemount divers and Independant doubles divers tend to forget gas planning for failure, not always forget gas planning for failure...What I see about sidemount divers is that they dive that way for conveniences other than gas planning and redundancy.

With all due respect... that's because the side-mount course isn't a technical diving course. If a diver hasn't done a technical diving course, then they shouldn't be in situations where technical diving planning and procedures are necessary.

A technical diver doing a side-mount course is one thing. They're still a technical diver, but use side-mount.

A recreational diver doing a side-mount is a very different thing.

They're still a recreational diver and subject to those common limitations because of their lack of technical training. Given those limitations, they obviously wouldn't have any more gas planning for failure than any other recreational diver.

The same applies to overheads/wreck penetrations. Recreational (Cavern / Basic Wreck) and Technical (Cave / Adv Wreck) levels have different limitations - which are derived from the capability provided by the training. The use of two cylinders, whether sidemount, backmount or slung pony, doesn't permit any greater spectrum of activity. Training alone permits that.

 

[Colliam7]

You're giving up on planning for second failure, though, since you can't easily share that 40 if your buddy loses their gas (more likely if they follow this configuration also) since it only has one reg. The most discussion that's related to this topic is on "team bailout" for rebreather teams. Go look up those discussions and see how you feel.

I may be jumping into an S-storm here (which is definitely not an equivalent of an S-drill). If you meant to use a quote from my post as a segue to making a comment intended for the OP, then disregard my response. But, since you used a quote from my post, and asked how 'you feel', I will respond, for me alone (not for the OP). I feel exactly the same way I did when I made the post. To avoid a misunderstanding - I very specifically said to the OP that 'you can do just that' - i.e. the OP could do what he was proposing, meaning as an individual diver. I said nothing about planning for the second failure - the buddy's gas supply. I said nothing about rock bottom gas management calculations, etc. In fact, at the risk of derailing the thread, I will take it a step further. Any diver going to 150', and anticipating / planning for a decompression obligation, should plan the dive as if it were a solo dive, with appropriate redundancy, and contingency plans. In those circumstances, you are on your own to get back to the surface, as is your buddy. In saying that, I don't intend to sound harsh and uncaring. If my buddy goes OOA at 150', I will do what I can to get us both back to the surface, without compromising MY safety. But, when a diver plans to engage in deeper, decompression diving, they should / must plan for redundancy, for contingencies, and that does not include having their buddy carry part of their gas supply. When I dive to 200', or even 150', I DO NOT plan for, nor do I have any right to expect, my buddy to have a sufficient gas supply to get me back to the surface.

 

[Mayor]

To the OP.... Research a good technical instructor and sit down to review your goals and what you need to safely get there. Your going to be in doubles why fight it.

 

[gsk3]

I may be jumping into an S-storm here (which is definitely not an equivalent of an S-drill). If you meant to use a quote from my post as a segue to making a comment intended for the OP, then disregard my response. But, since you used a quote from my post, and asked how 'you feel', I will respond, for me alone (not for the OP). I feel exactly the same way I did when I made the post. To avoid a misunderstanding - I very specifically said to the OP that 'you can do just that' - i.e. the OP could do what he was proposing, meaning as an individual diver. I said nothing about planning for the second failure - the buddy's gas supply. I said nothing about rock bottom gas management calculations, etc. In fact, at the risk of derailing the thread, I will take it a step further. Any diver going to 150', and anticipating / planning for a decompression obligation, should plan the dive as if it were a solo dive, with appropriate redundancy, and contingency plans. In those circumstances, you are on your own to get back to the surface, as is your buddy. In saying that, I don't intend to sound harsh and uncaring. If my buddy goes OOA at 150', I will do what I can to get us both back to the surface, without compromising MY safety. But, when a diver plans to engage in deeper, decompression diving, they should / must plan for redundancy, for contingencies, and that does not include having their buddy carry part of their gas supply. When I dive to 200', or even 150', I DO NOT plan for, nor do I have any right to expect, my buddy to have a sufficient gas supply to get me back to the surface.

Yeah my comment was intended for the OP, sorry.

That said, carrying gas for your buddy does two things: it gives you gas if there are two failures, and it gives you more gas if there's only one failure. One thing it does not do is make me reliant on my buddy for reserve gas--the buddy reserve is in addition to my own reserve.

 

[Pullmyfinger]

Another way to approach this might be to ask yourself why or why not.....the three of you would all go through intro to tech and AN/DP together all with completely different gear configurations?

When I approached my instructor, it was never with ......."This is the gear I already have. Can I just do the class with what I have?"

Even though you can do the class with a big single and H-valve and one deco tank, the fact that each of your buddies have two different configuration would just complicate matters.

What are the advantages for you and your buddies in taking this class together while each of you are wearing different rigs?
One in a single, one in a doubles, and one with side mount/independent doubles?
Then on top of it, you want to add a stage bottle to your setup.......It all makes for an interesting discussion, but your instructor has the final say on it.

Post back on what he says....I'm curious about it after reading your thread.

I'm sure it could be done, and there are probably instructors out there that might do it...but why???
What are the advantages?

Either way...have fun in your training!
All of your gear is going to "fail".
I was surprised at how often my regulators seemed to freeflow. ;-)

-Mitch

 

[DaleC]

What I see about sidemount divers is that they dive that way for conveniences other than gas planning and redundancy... but when the depth gets deeper than is safe on single tank, or the situation gets more complicated than can be safely planned for more than a single failure, it makes more sense to dive manifolded doubles. Redundancy is king.

I still don't get that. I dive independent doubles (same as sidemount) specifically for redundancy in anticipation of a failure, as most of my diving is solo. It is often said that manifolded doubles are better because, with ID's a failure leads to the loss of 1/2 ones gas. But to me that is a positive. It also means I can only lose 1/2 my gas. With manifolded doubles one may preserve more gas but one can also lose all ones gas. Independent doubles, no matter the configuration, offer true redundancy. Manifolded doubles only offer conditional redundancy.

However, in regards to the OP, diving those conditions, with an ongoing set group of divers, does make a strong case for standardization.

 

[waterpirate]

I took Wookies comment to mean that more people are going sidemount cause it is what the cool kids are doing. Their choice has little foundation in gas planning or restrictions to be overcome. I am a little $hit or hurt my back is also gaining traction in the choice.
Eric

 

[Pullmyfinger]

Side mount does seem like it's becoming more trendy.

I listened to a Pod Diver pod cast interview a while back with one of the people credited with the development of the side mount configuration.

He described a pretty specific set of circumstances for their use...... they seem to have gained favor among a variety of divers now-a-days. Much different that what was discussed in the interview......I guess there's a side mount evolution of sorts out there.....but I haven't been keeping up with it.

Is side mount more of a regional development? Or is it a case of divers having issues with big doubles rigs, that is driving the apparent growth of side mount.

I've never seen a side mount diver, but it does get talked about on the forums a lot.
I was just curious.

-Mitch