Such a thing as too much air or no need for redundancy? (long and rambly)

[happy-diver]

Can you get these over in America

Double 55s 232bar 3365psi

7 litre 55 cf 7.6 kg 16.8 lb 605 mm 23.8 in 140 mm 5.5 in -1.0 kg -2.2 lb -3.0 kg -6.6 lb

Now if you want to get into doubles for doubles sake and unless you're a light breather OR stay rec
MAGNIFICENT TANKS
Long and slim 3364.88 psi

Faber 232 7L Cylinder

 

[DeepSeaExplorer]

Need to check the local charter boat regs. I know of some that do not allow two sets of doubles because if several people use them they take up too much room on the boat. Basically you are allowed two main tanks and one pony.

I’ve been on day trips where 4 dives were scheduled, but divers were only allowed three tanks and one deco bottle. With the deepest dive being 150fsw, that’s a head scratcher. A set of AL-80s is a good start.

 

[Steve_C]

that’s a head scratcher.

Yes

To me the purpose of dives is to spend time on each dive and not just say I dove X times on Y tanks.

 

[84CJ7]

Just to go over things again, I missed the LP112's I was looking at and don't expect to see another set used at a good price any time soon though if I do making those my new single tanks with a pony backup would probably be my preferred choice. I picked my 19 pony after seeing all of the sizes lined up at a dive shop and working out what each would give me for time, its bigger than I originally wanted so I consider it my limit.
Since I don't want to rely on redundant buoyancy that I would have to deploy first (instant up is a necessity for me) doubling up my 85's or really any full size doubles are off the board unless I get into dry suit diving which is not happening any time soon for various reasons.

This is the closest thing in the US that I know of to what you posted but they are only rated for 2640 psi so I don't know how the physical specs compare to the euro version:
DGX Custom - Doubles Package - Faber LP-50 | Dive Gear Express®
I do love that they are light enough where they would weight almost the same as the single lp112. The valves and extra regulator would push the weight up a bit i'm sure.

The drawback to that is the massive cost increase since with those size tanks I would need to switch between dives and so I would need two sets of them. That's the main reason I haven't jumped at that plan, the other reason would be the hassle of having them on great lakes charter boats since I'm sure they don't fit the tank racks on the benches correctly (or do they?) and the above mentioned feelings of many boats about multiple doubles sets on rec dive days.

I have seriously looked at HP100's in the past but I wonder about the longevity of all parts involved in holding back the extra 800 PSI. It seems like I would get more life out of both the cylinder and the 1st stage with the lower pressure, especially since I rebuild my own stuff and only go through it every few years.

 

[Bob DBF]

I have seriously looked at HP100's in the past but I wonder about the longevity of all parts involved in holding back the extra 800 PSI. It seems like I would get more life out of both the cylinder and the 1st stage with the lower pressure, especially since I rebuild my own stuff and only go through it every few years.

The HP 100 tanks and valves are made for the pressure, and unless you are diving a really old reg, like some of mine, any modern reg is made for that pressure, and more, so why baby them.


Bob

 

[happy-diver]

and yes very expensive but on a brighter note, two sets of double 55s will fit where the two singles go

 

[rjack321]

I have seriously looked at HP100's in the past but I wonder about the longevity of all parts involved in holding back the extra 800 PSI. It seems like I would get more life out of both the cylinder and the 1st stage with the lower pressure, especially since I rebuild my own stuff and only go through it every few years.

LP vs HP has no functional difference on regulator lifespan or performance. Properly maintained steel tanks which avoid getting water to rust out the insides will probably outlive you and your diving career.

(the exception being if you want to use an old double hose reg or something like that)

 

[NAM001]

I’ve always read here that double AL80s are OK for a 7mm wetsuit. Steels belong with drysuits. You’d need a lift bag for redundant buoyancy with steels diving wet. Or a wing with double bladder, but that opens a whole different can of worms. Go look for the threads here. Have been a number recently.

For me the rule has always been doubles equals dry suit

 

[happy-diver]

We have used wetsuits with steel twin tanks before during and after drysuits

and I've got factory rated 300 bar 4350psi, fifty year old double hose din regs

it's all about the connection not the reg and the misinformation and paranoia

 

[DeepSeaExplorer]

For me the rule has always been doubles equals dry suit

Generally true... however, there are places where the water is warm enough to do long dives without going dry.

In South Florida, the surface water temps can hit 92-96F in late summer. If there’s no thermocline, bottom temps can be toasty. I’ve dove double AL-80s with a 2mm shorty. I’ve actually had problems with sweat getting in my eyes during long swims.