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

[kensuf]

Can you manage AL80s? It'll be easier to get a set of double 80s filled to 150 cubic feet than a set of LP50s filled to 150 cubic feet.

 

[-JD-]

Hi, @kensuf.

Time will tell ... at this point I'm still at the hobbling around stage, waiting to start PT, with surgery possible depending on progress. I'm looking forward here, trying to map out the range of possibilities.

I imagine that "normal" size doubles will have to be a limited time/distance thing out of the water for at least a while. A 110+ pound rig compressing my spine is not going to be helpful. My rig is setup with an H-harness using a separate waist belt to allow me to cinch it tight and carry much of the weight on my hips, which is helpful.

AL80s would certainly be an option if I'm renting, but I have 6 HP100s that I can set up with L/R valves.
With my HP100s as manifolded twins I was using 10ish (I was still dialing in my configuration last season) pounds of lead on my waist with my DS (Fusion with light-mid weight thermals).
I can get good (3800psi) fills If I want here for 210+ in a set.
Pretty much the same net weight with less lead and more gas.

Am I missing something if I'm using decent thermal protection? Obviously diving rash guard or 3mm the AL80s might be safer.

ETA: If I'm travelling to, say, your neck of the woods for training, I'd be driving and would be able to bring my tank fleet. My dive/travel vehicle is an E350.

 

[tbone1004]

Can you manage AL80s? It'll be easier to get a set of double 80s filled to 150 cubic feet than a set of LP50s filled to 150 cubic feet.

that is the real caveat. LP50's when "cave filled" are 50*(3600/2640)/1.06=64cf each, a pair of them is call it 130cf for easy math. Double 80's are 77*2=154.
What's important here is that most places won't cave fill LP cylinders so you're stuck. I wouldn't allow it with 50's at working pressure but would make a concession for it given physical restrictions if they were cave filled. I agree that AL80's are going to be a better option though, but are about 25lbs heavier plus whatever lead you have to wear, so that may not be an option. I do very much wish Faber would make FX versions of the LP50's...

 

[MichaelMc]

What about a limited backgas deco class? The gas needs would be a closer match to your back. IANTD has a rec. deep deco: 132' 10 minutes of deco. But only two in the US teach it, in FL, and you need their essentials class first. They also have rec. trimix, which they combine with various classes, like normal rec. deep. Padi only adds trimix later. RAID can add trimix to deep, but seem to not have a backgas only deco class.

 

[-JD-]

that is the real caveat. LP50's when "cave filled" are 50*(3600/2640)/1.06=64cf each, a pair of them is call it 130cf for easy math. Double 80's are 77*2=154.
What's important here is that most places won't cave fill LP cylinders so you're stuck. I wouldn't allow it with 50's at working pressure but would make a concession for it given physical restrictions if they were cave filled. I agree that AL80's are going to be a better option though, but are about 25lbs heavier plus whatever lead you have to wear, so that may not be an option. I do very much wish Faber would make FX versions of the LP50's...

I probably could get 3600 fills here, but I'd want to get a specific OK beyond say 3000 since it is not my compressor. N FL, I imagine I might get cave fills without too much hassle if I end up training there (which is something I've been considering).
I agree a FX60 in and LP50 form factor would be sweet.

See my comments to Ken above your reply re: AL80s vs my HP100s. I've got the 100s and the net weight pretty much works out the same with a bonus of 30% more gas. Either way, it looks like I'm going to have to be smart and figure out how to make full size Independent doubles work for the deeper/longer dives. I think that is doable. Full-size banded doubles are just off the table from a logistics point of view unless I employ a personal tank monkey.

 

[tbone1004]

@-JD- in cave country, you can get 3600psi fills with no issues. Doing AN/DP in cave country without a full cave card is a different discussion since there aren't a whole lot of places deep enough in open water to do it...

 

[-JD-]

What about a limited backgas deco class? The gas needs would be a closer match to your back. IANTD has a rec. deep deco: 132' 10 minutes of deco. But only two in the US teach it, in FL, and you need their essentials class first. They also have rec. trimix, which they combine with various classes, like normal rec. deep. Padi only adds trimix later. RAID can add trimix to deep, but seem to not have a backgas only deco class.

Actually the "IANTD has a rec. deep deco: 132' 10 minutes of deco." is probably pretty much what I'd be likely to end up doing max in OC from this training in the near future.

ITT & AN/DP/HT are gateway classes for Rebreather and should I go that route Cave.

 

[-JD-]

@-JD- in cave country, you can get 3600psi fills with no issues. Doing AN/DP in cave country without a full cave card is a different discussion since there aren't a whole lot of places deep enough in open water to do it...

I've been perusing @kensuf s site and he does a boat dive to deal with that. I don't know what others do.

 

[tbone1004]

I've been perusing @kensuf s site and he does a boat dive to deal with that. I don't know what others do.

Most just teach cave students and leave the boat diving to the instructors on the coast for open water training.

Actually the "IANTD has a rec. deep deco: 132' 10 minutes of deco." is probably pretty much what I'd be likely to end up doing max in OC from this training in the near future.

ITT & AN/DP/HT are gateway classes for Rebreather and should I go that route Cave.

If you're thinking about going cave, you can do that training with LP50's, though I would recommend having 2 sets of them for training since mid-day fills tend to be frowned upon. I would recommend doing ITT and cavern/intro first, and then see if you can go to the HP100's after some more healing time for AN/DP

 

[-JD-]

Most just teach cave students and leave the boat diving to the instructors on the coast for open water training.



If you're thinking about going cave, you can do that training with LP50's, though I would recommend having 2 sets of them for training since mid-day fills tend to be frowned upon. I would recommend doing ITT and cavern/intro first, and then see if you can go to the HP100's after some more healing time for AN/DP

Food for thought. ITT and Cavern in MX cenotes would be pretty awesome. I'm going to have to get back in the water in singles and then get IDs sorted out to my own satisfaction before making any actual decisions. Fortunately, here I've got some buddies that I believe will help me with the logistics as I'm feeling out my capabilities. I'm hoping for a cautious start later in June, but that is a complete, and maybe grossly optimistic, guess.

And cave on LP50s is not gonna happen for me. With 1/6ths I'd be measuring my penetrations with a ruler. Think Jethro Tull . If I go cave, it will probably be on RB. Lots of steps before getting there.

Thanks, I appreciate your thoughts.