Independent Doubles!

[StreetDoctor]

Street doctor, I reread the thread and see that my "bloodlust" went to far. I've deleted the offending post as I see you aren't trying to pick a fight.
Sorry for the attack.
Soloists... Sheesh

Haha no worries, I've never dove independent doubles or been around anyone that has but I know what has worked for me so far

 

[Sas]

You're telling me! After diving in jacket BC's, Back inflate's, and finally now a BP/W that is "koolaid" compliant. There are only a handful of local divers that I've dived with that dive like me, the rest most think we are crazy.

I'm talking about stuff a bit beyond what BC one wears... But even say with the simple BC example, I have no problems wearing all sorts of BCs if I have to borrow one. Some people, you'd have to claw their BPW out of their cold dead hands.. At the levels of diving most people are doing, it's a bit weird to be so dependent on a bit of gear to be comfy. At new diver level, sure but not beyond that.

 

[DaleC]

Dale I agree that adapting to different gear should be easy enough once one has a bit of experience. I've had to borrow various setups over the last while (as I didn't have my own) and learned that it is no big deal. Before this I had fallen into the standardization trap where I thought that things should only be done one way. If one is a comfortable and competant diver all sorts of setups should be fine. I get the impression that some divers don't get much exposure to divers in different setups. Locally there are so many different styles of diving I think some people on scubaboard would have a heart attack seeing them. But some of these people have been doing all kinds of diving for 20 or 30 years... I might not think it is ideal (like backmount independents ) but it is clearly working for them.

Exactly!!!

I dive with a loose local group and there are many many configurations out there. In the OW setting I think they can all (most?) be valid. The problem I have always had with certain schools of standardization is that it is based on a worst case scenario (or if one likes "most technical" scenario). For very demanding and committed technical dives I do believe there is a "best" configuration (for the most part) and I understand that the same system can be used in reverse (for less and less demandng dives) but it does not mean that it is the only viable rig for less demanding dives.

I look at the dive, what I value, and the rig that gets me there. It also helps that I strongly believe that adaptation is a valuable skill. If one dives with a standardized team it might not be - but if one dives with people using many different systems, being able to navigate swiftly between them is an asset.

 

[Gilldiver]

So far I have not read many post from divers who have actual dove independent back mounted doubles, just a lot of crap from people who think they know how and what the problems can be. I also see a lot of real deep diving (below 200') and cave bias which was not done much at all with independent 72's or 80's.

Leaving the side mount guys out of this as they have it figured out, even if they don’t know it, I’ll go into a major factor with any back mounted independent system that none of you seem to have figured out.

All of you have talked about gas management, but when I started in the 80’s we never saw divers dead from gas management, we saw then dead from 2nd stage and gauge management issues.

Regulator and Gauge Management

It is imperative that you can tell which tank you are on by touch. That means that you can tell which 2nd stage goes with which gauge, quickly and easily.

In the 80’s it was very common to see independent 80’s and a pony on a diver doing deep dives to 200-250 feet. That meant that you would have 2 or 3 2nd stage regs around your neck. If they were all the same shape, it got hard to tell what tank you were on and how much air you had in that tank. More then a few divers were found dead on the bottom with full back tanks and an empty pony. What they did was mistake their pony reg for one of the back tank regs, got to the bottom, ran out the pony and panicked. Remember, this was the bad old deep air days as that was all we had, getting narcked was always a factor.

How many divers worked around this problem was to use Poseidon regs (one cyklon AKA Thor or the Hockey Puck and a Jetstream AKA Odin or a Shower Head) on the back tanks and a more standard 2nd stage like a USD Conshelf on the pony. These 3 2nd stage shapes are very easy to tell apart by feel.

Off of one of the back regs was a single gauge and off the other was a gauge/depth gauge console. The pony did not have a gauge. Many times the 2nd stage hoses and 2 gauge hoses were duct taped together to keep it all manageable.

The side mount guys never have this problem as the tanks and regs are by the distance of your body separate and confusion of which tank you have etc. is very hard to do.

Independent doubles are just one tool in the tool box, any particular diver may not use that tool, but it can be in your box if at any time you need it.

 

[DaleC]

Good post Pete and a great discussion point.

I read about that and decided to have a stategy of always bungying the left post reg under my chin and having the right post reg on a longhose. That way I can always tell which tank I'm breathing. I also have the spg's clipped off on the same side of the body as the tanks. Left SPG - left tank. Right SPG - right tank.

A mod I have been contemplating but haven't gotten around to yet is to route the SPG's straight down the shoulder webbing to the chest D rings. I just don't have the right sized HP hose. If done right (I think) it would be more streamlined, eliminate the 30" hose, put the SPG right in view with just a flick and eliminate clipping and unclipping. I am very curious if this was ever contemplated during the HOG rig development days and what the percieved pros/cons would be. I asked once in the HOG section but never got a response.

I think I will take some photos of what I mean and start a thread to see what's what. Better get my flame retard suit out of the closet for that one.

 

[Gilldiver]

Good post Pete and a great discussion point.

I read about that and decided to have a stategy of always bungying the left post reg under my chin and having the right post reg on a longhose. That way I can always tell which tank I'm breathing. I also have the spg's clipped off on the same side of the body as the tanks. Left SPG - left tank. Right SPG - right tank.

A mod I have been contemplating but haven't gotten around to yet is to route the SPG's straight down the shoulder webbing to the chest D rings. I just don't have the right sized HP hose. If done right (I think) it would be more streamlined, eliminate the 30" hose, put the SPG right in view with just a flick and eliminate clipping and unclipping. I am very curious if this was ever contemplated during the HOG rig development days and what the percieved pros/cons would be. I asked once in the HOG section but never got a response.

I think I will take some photos of what I mean and start a thread to see what's what. Better get my flame retard suit out of the closet for that one.

Then you have a system which looks to be easy and works for you. This is a lot more then most divers have when they first start independent tank diving. But if you don't have a system, all the gas planning in the world will not help you as you can't tell one tank/reg/gauge from another.

Which is why I say that all the above is crap as none have described this basic of all problems and are only blowing smoke.

The HOG rig came about more into the 90's when we started having choices in tank size and manifolds. Back in the 70's/80's your choices were the sherwood doubles manifold and old steel 72's, 80's and some had aluminum 100's. But by the time the 100's and 120's came about, going independent fell out of use as the larger tanks would be manifolded with the new manifold types. My first set of "large" tanks were the Sherwood HP 100's with the narrow thread manifold.

By the way, as soon as good solutions to manifolding came out I went to those manifolds and have almost never gone back to independents. But the few times I was some place where a deeper dive could be done and no manifolded doubles around, I have gone back to independents.

 

[AndyNZ]

1.) I've always got 1000psi I can donate to an OOA diver in any OW dive How much more do they need?

Curious as to why, from a solo diver perspective, that this is a concern?

 

[DaleC]

Curious as to why, from a solo diver perspective, that this is a concern?

Good point. I dive solo but I don't always know if anyone else in the area might also be diving. I figure if someone sees me and happens to go OOA I want to be able to respond. It is the same reason I have a longhose. From a solo perspective I don't need it either.

This same type of discussion comes up in solo threads regarding the use of an octo. Some soloists believe in diving single reg rigs (which is ok if one is shallow and plan to CESA, with other divers who expect it, truly solo) but I don't always know who else in in the ocean. Given the fact that many new divers don't learn adequate BB skills I wear an octo just in case (on a single tank rig of course). Often times I meet up with a group of buddied divers in the parking lot but then go off to solo. I enjoy the companionship during the SI's.

BTW here is the link to the thread re: SPG routing if anyone is interested http://www.scubaboard.com/forums/hogarthian-diving/320103-routing-spg-along-shoulder-webbing.html#post4982316

 

[Gilldiver]

Curious as to why, from a solo diver perspective, that this is a concern?

Perhaps it is because you may be that OOA diver, that 1000 psi is your reserve.

When we did independents we would switch every 500 psi. Or, we would take one tank half way down and breath the other for the rest of the dive.

If you did the half tank system, you could:

1) Take 3 80's on the boat
2) Breath one tank to 1500 psi, then finish the dive on the other
3) Get back on the boat, change out the tank with the lowest pressure (usualy the tank you finished the dive on with the 3rd, full, tank).

Then for the second dive you had a full tank and a half full one.

In the air days this was all you needed for a second dive in the 60-120 foot range as we did not have deco gasses to accelerate the deco times and were using Navy Tables. So, you had to keep the second dive short.

 

[DaleC]

1,2,3 is exactly how I do multi dives. In fact I always leave 2000 - 1500 in my left tank (depending on the profiles) and swap out the right. This is because I have one lefty valve and two righty valves.