Solo Cave Diving: Equipment Configuration

[PEDiver]

Apologies if this has been discussed before. If so, please feel free to point me to the previous posting.

As a little background, I'm currently diving a manifolded BM configuration in a DIR setup. I am very comfortable in BM and at this time will most likely continue down this route until SM becomes necessary. A majority of the cave divers I dive with are in SM configurations.

I've recently started doing more solo diving, and as a consequence, have been giving equipment configurations a lot more thought. My current go-to setup are my doubles plus a buddy bottle.

My main question is this: would it be more prudent to use independent doubles for solo cave diving? I know manifold failures are very rare, and I've personally never had any issues, but the possibility remains for a catastrophic failure. To my understanding, using ID would be similar to a SM configuration -- outside of the ease of "feathering" a SM tank. Each ID would have a dedicated SPG and the hose routing would remain the same as my current setup. With ID, you would simply breathe down each tank in the same way you would in SM so as always to have reserve in one tank if the other had a catastrophic failure.

Most of the cave divers I know that solo dive use a SM configuration to have complete redundancy. Why don't more divers use IDs?

Would love to hear the community's thoughts here.

 

[Tracy]

Backmount also has complete redundancy and the ability to use all available gas with a reg failure.

 

[Gone for diving]

I prefer manifolded, it's better IMHO,
I just read and article on bill main,

He doesn't even use an isolation valve, he just has a cross bar, which I thought was interesting, I do like the isolation valve,
But I think it can mess some people up,
But I have been turning bolts and valves most of my life, and find it hard to understand how some people mess up rotations...

Other than yoke orings, when has anyone seen an oring fail on a tank? Unless the orings are really old, or loose valve or sun can get at it, ozone or something like that,
If you have good bands, and are tight, manifolds are really reliable

 

[lostsheep]

Other than yoke orings, when has anyone seen an oring fail on a tank? Unless the orings are really old, or loose valve or sun can get at it, ozone or something like that,
If you have good bands, and are tight, manifolds are really reliable

A friend of mine had a tank o ring blow last month while the tank was sitting in her closet at home.

 

[rjack321]

Most of the cave divers I know that solo dive use a SM configuration to have complete redundancy. Why don't more divers use IDs?

Because manifolds are extremely reliable. Probably more so than the slightly narced human brain trying to decide which SPG is telling them what on independent doubles.

That said backmount, solo, OC cave divers are:
1) quite rare nowadays,
2) are almost always in very benign familiar caves like the front 2,000ft of Ginnie (FL State Parks prohibits solo diving),
3) often diving with stages leaving backgas alone, and
4) usually fairly old locals and set in their ways. Indy doubles have never been a recommended cave diving option with a buddy, so nobody specifically sets aside tanks this way to use for the occasional after work solo dive either.

 

[tbone1004]

it's complicated but @rjack321 hit it on the head pretty well.
I know of one guy who dives indy doubles who is an old local *in his 70's*, though he doesn't usually solo dive, but has always dove indy doubles since the 60's. He has a couple sets of "normal" doubles but the isolator is only opened to get them filled, closed when diving.
Bill is also the only cave diver I know who is still diving a straight crossbar.

I do a decent bit of solo diving in doubles, but it's always fairly benign caves, no more than about 1500ft of penetration and nothing terribly exciting or I'm in sidemount. Things like the first dive of the trip going to Table Rock in LR and back again, small dives compared to normal but I also do a lot of teaching so it's very rare that I actually have a "teammate" on benign dives, usually only on big stuff so it's a different mentality.

If it were me, I would just bite the bullet and go sidemount *coming from one who has been sidemount cave diving for over a decade and did all of my cave training in sidemount but still prefers doubles because I find them easier to get into and out of the water* vs indy doubles. If you go indy doubles, people will look at you funny, straight crossbars are near impossible to find, and carrying a stage on every dive is properly annoying. That said, if you do carry a buddy bottle then add a loop bungee to your harness so you can sidemount that bottle instead of having it dangle.

 

[PEDiver]

I do a decent bit of solo diving in doubles, but it's always fairly benign caves, no more than about 1500ft of penetration and nothing terribly exciting or I'm in sidemount.

That is very similar to what I'm doing. Mostly shorter, relaxing dives to practice reel running and technique (especially in caves with high flow). Any "big" dives are done with a buddy.

That said, if you do carry a buddy bottle then add a loop bungee to your harness so you can sidemount that bottle instead of having it dangle.

Currently using a bungee choker to keep the bottle more streamlined and in trim but I will look into adding a bungee loop to the harness instead. Nothing worse than a dangling stage bottle with enough room for another diver to swim through.

 

[Gone for diving]

A friend of mine had a tank o ring blow last month while the tank was sitting in her closet at home.

I would really love to see a picture of how the oring extruded out,

Something must not have been right
or something not assemble right?
I am very curious, because I use oring alot in my line of work,
Usually something like that application would fail because of heat wreaking the oring over time,
extrusion is usually wrong assembly, wrong oring, or something like that,

 

[rddvet]

I don't think moving to independent doubles or sm is making solo diving significantly safer. A better choice is to add a stage. Then you have two options. Only breathe the stage, don't touch the doubles and save the doubles for an emergency. Other option is to breathe backgas very conservatively, and save the stage as backup.

 

[lostsheep]

I would really love to see a picture of how the oring extruded out,

Something must not have been right
or something not assemble right?
I am very curious, because I use oring alot in my line of work,
Usually something like that application would fail because of heat wreaking the oring over time,
extrusion is usually wrong assembly, wrong oring, or something like that,

I don't think she took pictures of it unfortunately.

I know the viz was current and presumably they swapped the O ring at that time. That said, if it's the shop that I think it is, they recently lost their best service guys; Point being we will never know if it was installation error or bad o ring.

My personal take on the matter is it doesn't matter. Failures are going to happen and I dive as if any component I am carrying can fail at the worst possible time; my plan is to be able to deal with it.