Diving with two tanks

[MikeSK]

Oh..im definetly gonna get training. I love taking classes. I didnt realize it was this "complicated". I see doubles and i think its just one big tank.

thx for bearing with me

 

[NC Wreck Diver]

Oh..im definetly gonna get training. I love taking classes. I didnt realize it was this "complicated". I see doubles and i think its just one big tank.

thx for bearing with me

OK Mike:

Taking a training class is a very good idea. I've been watching the posts. You will understand this from SB, but having a set of doubles in front of you, and the manifold and bands mounted will help much more than posts on the internet. I have that exact XS Scuba manifold that you see the diagram of on one of my sets of doubles. The other two sets are Blue Steel's, but they are basicly the same.

Take note of this. Another diver told you to rig your two regs, with the primary reg on the right, and pressure gauge on the left. That system works fine, and it's the way he wants to dive. Not a problem. I do EVERYTHING on the right hand side port, my Primary reg, my AIR 2 BC Inflator hose, my HP line to my SPG, and, if I'm diving a drysuit, a power inflator for that too. I only have an octopus on the left hand port. It's my personal choice that if ANYTHING fails on my primary MK25/A700 - HP & SPG - AIR2 Power Inflator Hose - and drysuit hose fails, I shut down the isolation valve, end the dive and surface, doing my deco hang or safety stop on the left hand tank/reg (MK10/G250). If I feel resistance on breathing that left tank (I'll know if it is getting low on air - my regs are finely tuned), I'll stop using this 'Backgass' and now use my 30 cu. ft. bailout bottle. Complete with a redundant regulator, including the 6"HP hose and SPG.

Don't forget, the isolation valve is always open. During filling, and during diving. So it is ONE BIG TANK. UNTIL you close that isolation valve. Then, at what ever pressure you are at in those doubles, you know have only 1/2 the gas that you did before you closed the isolation valve.

So just to recap, for me (you will set up your doubles the way YOU want with your regulators), I dive all my gear on the right post, except my Octopus, which is on the left post. Isolation valve open (always) except for any problem. One big tank with it open, 1/2 the gas when it's closed in an emergency. Then, for added redundancy, I sling an independant 30 with it's own regulator and SPG.

Bear in mind, I have never had an emergency that I NEEDED to do this. I practice it, but I never needed to do it. It's just good to be prepared. If, by a strike of lightning, everything else fails, I have an independent bailout bottle, slung on my BC.

I know this sounds like a lot of overkill, but if you ever seen someone drown, you will know why I do what I do. Good luck. You'll get it.

 

[PfcAJ]

Oct on the left post? Cool, that works ONLY for OW diving, and no where else.

The second you move into an overhead (wreck penetration, maybe), its a horrible choice, as is putting ALL your inflation stuff on one side.

Carrying all your eggs in one basket doesn't seem like a good idea to me...

 

[NC Wreck Diver]

Oct on the left post? Cool, that works ONLY for OW diving, and no where else.

The second you move into an overhead (wreck penetration, maybe), its a horrible choice, as is putting ALL your inflation stuff on one side.

Carrying all your eggs in one basket doesn't seem like a good idea to me...

Hey PfcAJ:

I understand your comment. This is the way I rig my doubles, and I have been doing it for years (a couple of thousand dives under my belt). I will penetrate wrecks with this set up, dive solo (with my redundant 30 bailout bottle) with it, so I use it for more than just for ONLY OW. If I'm diving in my drysuit, I only use very little gas, just to eliminate suit squeeze, not bouyancy. So I'm not worrying about that. If my BC hose was to fail, I would manually inflate it if needed, but once my bouyancy is trimmed, I do pretty well. I see a lot of people add and dump, add and dump to their BC's, but that to me isn't good bouyancy control. I rarely do alot with my BC power inflator, maybe a small puff if I really need it, but more of venting to control ascent rate. As I mentioned to Mike in the OP, this is only MY way, and not intended to tell him, or anyone for that matter that this is what THEY should do. A 'horrible choice' to you may be just the ticket for me. I have reasons for my set up for my doubles, and I don't feel like I will change it.

But that is the great thing about about SB, we get to see how others do their diving and pick and choose what we think is good, and what we think is bad. We didn't have anything like this back in the mid 80's, when I started diving. I was trial & error, watch & learn, and the school of hard knocks.

Safe diving to you.

 

[PfcAJ]

It works just fine till something goes wrong.

 

[NC Wreck Diver]

It works just fine till something goes wrong.

Well, I think I explained that completely in my previous post. But we can always agree to disagree. I hold stock in diving for 25 years, diving every weekend like most people here on SB, and never had a close call in any diving aspect. I've pulled some up from the bottom, and learned from their mistakes. I unfortunately pulled one up from the bottom that drown in 110 feet, and learned big time from his mistake. I think about it every time I gear up to dive. Hopefully, you have not had to do this, but if you did, you may know what I mean.

I did the whole Divemaster/AI training years ago, but I never kept my insurance covered. No interest in being sued, no interest in teaching and dive for my own pleasure. I don't need a deck of c-cards. I believe I know what I'm doing, and it looks like you do too. I only show an Advanced card, a Rescue card and a Nitrox card. That keeps me in the water.

I have evaluated all my gear, my experience and how I like to dive. Nothing has gone wrong, and I don't believe it ever will. I don't need to be a daredevil and don't need to prove anything to anybody (nobody is interested anyway). If I thought something was 'wrong,' I wouldn't dive it until it's fixed.

 

[PfcAJ]

Well, I think I explained that completely in my previous post. But we can always agree to disagree. I hold stock in diving for 25 years, diving every weekend like most people here on SB, and never had a close call in any diving aspect. I've pulled some up from the bottom, and learned from their mistakes. I unfortunately pulled one up from the bottom that drown in 110 feet, and learned big time from his mistake. I think about it every time I gear up to dive. Hopefully, you have not had to do this, but if you did, you may know what I mean.

I did the whole Divemaster/AI training years ago, but I never kept my insurance covered. No interest in being sued, no interest in teaching and dive for my own pleasure. I don't need a deck of c-cards. I believe I know what I'm doing, and it looks like you do too. I only show an Advanced card, a Rescue card and a Nitrox card. That keeps me in the water.

I have evaluated all my gear, my experience and how I like to dive. Nothing has gone wrong, and I don't believe it ever will. I don't need to be a daredevil and don't need to prove anything to anybody (nobody is interested anyway). If I thought something was 'wrong,' I wouldn't dive it until it's fixed.

That is precisely where we differ.

 

[aquaregia]

I'm legitimately curious about something on that setup. I'm new to diving, and I promise I'm not trolling or trying to fan fires, etc.

Why do you put the octo on the left and everything else on the right, rather than the octo on the right and everything else on the left?

Thanks

 

[PfcAJ]

Because when you pass the reg on the left post to an out of gas diver and go to exit your wreck or cave, it rotates OFF if you hit the ceiling. Thats a real big issue for the guy with no gas. The reg you donate needs to be on the right post (since it rolls ON). This is the basis for the rest.

Splitting up your buoyancy (wing on the right, DS on the left) is a good idea so you don't always have to orally inflate should you lose the left post. Plus you have the option of descending, should the need occur. Hard to orally inflate a drysuit Should you lose suit inflation, you can add gas from the wing LP hose, or get argon from your buddy (which is also on the left side, so you don't trap the long hose that you're breathing on the right side) when diving mix. Also, although a rare occurrence, you can use the inflater as a tertiary reg for a breath or two if you're passing a tight restriction while on your backup reg and it rolls off.

Spg on the left so if during the course of your dive, you can easily tell if the left post is off (since you aren't breathing it) or if the isolator is closed. The spg pressure won't drop if either if those two are closed, since you're breathing off the right post. Naturally, you need to check your valves whenever you contact the ceiling, regardless.

A logical hose setup allows for the max amount of contingencies to be covered and works in all kinds of diving, be it cave, wreck, reef, scooter, etc while maximizing safety and simplicity.

 

[aquaregia]

I should have specified more, I suppose. I was wondering why NC Wreck Diver had the bulk of his devices on the right and the rest on the left rather than the other way around, for exactly the reason that you mentioned. I didn't want to get into any of the other particulars because I could come up with at least one reason that someone might want to do it that way, and I didn't want to get into a right vs my way sort of thing. I think NC Wreck Diver made it very clear that this is his way and that he isn't promoting that anyone does it his way, or even dive with him. However, I couldn't come up with a reason to put the active devices on the "safe" post and the backup on the "silent" post, and I was sort of curious why. The only thing I've been able to come up with (which I only thought of after I posted) is hose routing, or perhaps "I didn't think of it until a thousand dives later, after which I was sufficiently happy/used to my setup". I can't imagine anyone would set up their gear exactly the same way for a thousand dives by accident.

Edit: I do think PfcAJ gave a nice explanation of his setup though.