LP50 Doubles and/or Backmount Independent Doubles Accepable for ITT & AN/DP/HT?

[-JD-]

@-JD- why not just manifold them? Why dive them as independents?

diving indy doubles isn't rocket science though. The only change to the regulators is a HP hose and SPG on the right post and some way to look at it. Either a right hip d-ring, or run it over and down the inflator hose. Other than that, it is figure out when to switch. The issue with that is that no one really dives or teaches independent doubles anymore, so you have to figure that out on your own based on what you believe. Unlike sidemount you don't really have to worry about balancing the tanks because it will cause you to roll over, especially with 50's, so you can switch whenever you want, so you have to come up with your own paradigm.

Even before my herniation clobbered me, I was finding that loading, unloading, moving, filling, racking my banded HP100s was a royal PITA. No convenient way to lift and carry with that amount of weight/configuration.
I could manage my single HP100s and 120s with no problem. Much less bending as one was easily within my arm-strength range. I could comfortably carry one 100/120 in each hand (well, 100s - the 120's are awkwardly long).

So I was planning on moving to unbanded IDs for the past year. It is all about the ease of moving single tanks around. Even more benefit when avoiding lumbar strain is critical. There is also the option to rotate the cylinders a little to give me easier access to the valves with my somewhat wonky shoulders. Downside is I have 2 separate gas systems so there is some gas inefficiency.

I really have just been looking for the right-for-me ID compatible or modifiable plate. I do have an ID adapter that I can use to get started on my existing plate, I just find it lacking elegance.

I've been running my left-post with an HP hose over the shoulder with a Pony gauge and transmitter on a modified splitter. I'll do the same for the right when I go ID.

I was going to use the "not rocket science" analogy but I rephrased so as to not come off too cocky.
A little reading and experimentation, a lot of practice ...

 

[MichaelMc]

I'm not sure ID is that complex on gas management. I'd get a quick breakaway for the long hose and just follow sidemount rules on alternating sides and checking which hose you are on before donating from mouth or breakaway at chest.

The razor breakaway clip is nice. I found tying them to the bolt snap is wise as they can separate and the connector float up and away. Fortunately, I learned that in a pool. RAZOR Break Away Connector /w RAZOR Bolt Snap

The flexibility of pulling them in and out makes sense. It seems you might want some custom cradle if you are doing that at the dive site parking lot. To prevent them rolling apart and over once unbranded. Unless they are standing on the ground, and not a bench or table at back level. (There is a "banding and unbanding" technique that involves hip-mounted d-rings, bolt snaps, and chest level bungee cord. It's even easy to do in the water. It may not be as easy as strapping on an assembled set of IDs though.)

I dove ID AL40s briefly, but then manifolded them.

 

[-JD-]

I'm not sure ID is that complex on gas management. I'd get a quick breakaway for the long hose and just follow sidemount rules on alternating sides and checking which hose you are on before donating from mouth or breakaway at chest.

The razor breakaway clip is nice. I found tying them to the bolt snap is wise as they can separate and the connector float up and away. Fortunately, I learned that in a pool. RAZOR Break Away Connector /w RAZOR Bolt Snap

The flexibility of pulling them in and out makes sense. It seems you might want some custom cradle if you are doing that at the dive site parking lot. To prevent them rolling apart and over once unbranded. Unless they are standing on the ground, and not a bench or table at back level. (There is a banding and unbanding technique that involves hip-mounted d-rings, bolt snaps, and chest level bungee cord. It's even easy to do in the water. It may not be as easy as strapping on an assembled set of IDs though.)

I dove ID AL40s briefly, but then manifolded them.

I will probably get some of the Razor clips for the LH. I think that I have them on my DRIS wishlist. I will probably try a Toddy-style double ender attached to the razor clip on one end and an oring around the reg adjuster knob on the other. For now I have a magnet "clip" for the LH and a necklace for the other.

Tanks will be mounted with separable (ScubaPro style) cambands (to avoid having to lift over) to the plate or adapter and loaded one at a time.

 

[UCFKnightDiver]

Just curious why you believe backmount is more practical for your expected dive locations? Honestly it sounds like you are making arguments for sidemount yourself as you're talking about moving single tanks around, etc. If diving off boats, you could potentially gear up in the water and clip your tanks to a line off the back to gear down. Conditions do have to be really nice to make this practical though and it likely needs to be ok'd by the boat beforehand.

 

[-JD-]

Just curious why you believe backmount is more practical for your expected dive locations? Honestly it sounds like you are making arguments for sidemount yourself as you're talking about moving single tanks around, etc. If diving off boats, you could potentially gear up in the water and clip your tanks to a line off the back to gear down. Conditions do have to be really nice to make this practical though.

Most of my diving now is at a quarry, often with medium size groups, and in very busy conditions. Making 2 trips to and from the water, and having to gear up and down twice presents traffic and group-timing challenges. Arguably, I can do single & pony in those circumstances, but I prefer to use those dives to build experience in my doubles rig if possible.

Partly it is also time to competentcy. BM, ID is a tweak to my existing rig with working out alternating breathing. Going to sidemount is a whole additional level of gear addition, reconfiguration, and learning to mount, trim, etc.

BM, if I can handle it, also means I don't need help on a boat.

 

[Manatee Diver]

Most of my diving now is at a quarry, often with medium size groups, and in very busy conditions. Making 2 trips to and from the water, and having to gear up and down twice presents traffic and group-timing challenges. Arguably, I can do single & pony in those circumstances, but I prefer to use those dives to build experience in my doubles rig if possible.

Are there stairs? Attach a tank hang rope to the stairs, a few dollars in rope/paracord can make a ton of them.

Well before the group is gearing up carry your tanks to a place near the stairs. Do you dive briefing. During gear up put on your drysuit and your harness, get to the water, chill a little to cool off. Then tank one tank hang it on the rope, go back get the other tank, and your deco bottle. Get in the water and put your two bottles on. That should take about the same amount of time as BM divers gearing up. Do you in water briefings, gear matching, S drill, et al. Put on deco bottle and start the dive.

As you get more experience you figure things out, but if properly planned it should be able to work together, mixed teams aren't unusual in cave country.

 

[Cdncoldwater]

@sabbe & @Jim Lapenta

Thank you both for the advise and analysis (Jim, super detail appreciated)!

I expect that most of my work will be land based, so my concern has been gearing up and walking in from a distance. The LP50s are roughly equivalent to an HP120 in effective capacity and from a carrying perspective, so hopefully, I should be able to handle them (If not, I'm getting toward the realm of diving with accommodations for even basic stuff) That would allow me to work through the ITT and maybe AN portions without bogging things down.

If, and how long it will be before, I can carry double HP100s on my back for any significant distance is an unknown I don't want to be stupid and re-injure. In part it will depend on if recovery is through PT & plain healing or if I end up with surgery. Carrying my tanks down and assembling by the water could be an option, even donning/doffing in the water if necessary. I'd prefer not to because it would be somewhat disruptive to the class. But I do absolutely get the need for sufficient gas capacity. So I guess that will have to be made part of the known equation going in.

I am also absolutely aware of the need to correctly, and conscious of reserve, alternate breathing when on independent cylinders. My thought has been that backmount ID or sidemount differ by mounting position not breathing technique. I plan to have this worked out and practiced before starting down the classes.

Given my current circumstances, I see the ITT & AN/DP/HT sequence serving me in 4 ways.
1) Honing buoyancy, propulsion, planning, etc skills and training beyond my expected operational limits.
2) The ability to safely execute planed dives with very short deco and/or execute dive profiles that would otherwise be no-stop, but with enhanced conservatism that puts me into limited deco.
3) The ability to deal with OH SH*T circumstances to the best of my available gas resources (beyond just blindly following the stop by stop directions on my dive GPS)
4) Aspirational at this point, but I think a RB may be in my future if I can make the economics work out. (I'm an engineer and long--lapsed SEL private pilot so I would enjoy the rigor and RBs are way cheaper). This is a stepping stone to RB.

Have you given any thought to doing a Solo course? I was looking for the same points as you and discussed ITT with my instructors, the head instructor suggested that given my back issues, current configuration (SM) that I pursue a solo course. I had no real interest in going into the full tech route as the dive opportunities are generally limited in my local area. I did gain a lot from the solo course, all instructors are tech divers/instructors, so they passed some of that mindset into the training as well, especially in the planning and gear configurations. I may pursue the IANTD Rec Trimix or tech side mount course to expand my skills/learning but it won't be my routine dive plan.

 

[-JD-]

Are there stairs? Attach a tank hang rope to the stairs, a few dollars in rope/paracord can make a ton of them.

Well before the group is gearing up carry your tanks to a place near the stairs. Do you dive briefing. During gear up put on your drysuit and your harness, get to the water, chill a little to cool off. Then tank one tank hang it on the rope, go back get the other tank, and your deco bottle. Get in the water and put your two bottles on. That should take about the same amount of time as BM divers gearing up. Do you in water briefings, gear matching, S drill, et al. Put on deco bottle and start the dive.

As you get more experience you figure things out, but if properly planned it should be able to work together, mixed teams aren't unusual in cave country.

Yea, it is an option ...

I'd like to learn sidemount anyway, but that was going to be a "play around with it" thing. I already have an SMS100 wing (I use it now with singles - HP120s frequently) and my SubGravity buttplate will hopefully be (back) in soon. I'm going to build my own rigging (stage style) and I have some webbing samples on the way (over the top I know, but I'd like to ID the "right" stuff for me) so I can do that.

 

[-JD-]

Have you given any thought to doing a Solo course? I was looking for the same points as you and discussed ITT with my instructors, the head instructor suggested that given my back issues, current configuration (SM) that I pursue a solo course. I had no real interest in going into the full tech route as the dive opportunities are generally limited in my local area. I did gain a lot from the solo course, all instructors are tech divers/instructors, so they passed some of that mindset into the training as well, especially in the planning and gear configurations. I may pursue the IANTD Rec Trimix or tech side mount course to expand my skills/learning but it won't be my routine dive plan.

Assuming I can get back in the water diving singles by summer, I plan to do solo this season. Has been my plan all along.
Not much more to do training-wise other than tech then. Cavern, I guess, but then I keep reading that I should probably just do Cave 1. Since either means travel, what is a few more days for Cave 1 ... And that meas ITT, AN/DP realistically.