Best place to buy doubles?

[CRDiver]

http://cavediver.net/phpbb2/viewforum.php?f=2&sid=1118a67663f6f2a20bb3253ffb080937

 

[KidK9]

I own a Luxfer Neutrally buoyant 80.

 

[jbisjim]

I just bought a pair of Faber 95+ tanks. They are LP 2400. My understanding is that my LDS got a deal a bunch of them, and from checking around they are a good deal

 

[mempilot]

The only thing to mention about buying used LP Steels is this. Within the first hydro, most LDSs will overfill the tanks to 3000psi. This gives you substantially more gas for the first 5 years. This allows me to use my lp98's as if they were much larger cylinders. After the first hydro, many shops will only fill to the rated 2640. I'll sell my Fabers at 5 years and buy new ones for this reason alone. That is unless I put together a fill station before then.

 

[roakey]

I own a Luxfer Neutrally buoyant 80.

Do you want to keep that as a single, or any other reason not to buy a manifold, bands and another NB 80 and make a set of doubles from it?

Sea-Elite Manifold: http://www.divers-supply.com/ (search on "manifold")
Bands (Highland or NESS): http://www.highland-millwork.com/ http://www.northeastscubasupply.com/

For NB80s there's a number of alternate sources for bands, NESS being only one. If you get something heavy like PST LP104s, Highland's the only way to go.

Roak

 

[pilot fish]

Hey all, Im looking at investing in a set of doubles to start my slooooow transition to technical training. Could anyone please recommend a good place to be looking rather than my LDS or diveriteexpress.com. I like the tanks Dive Rite has, just looking for some alternate suggestions. Thank you.

Not sure I know what doubles are but I'm thinking it's two tanks in place of one? Can a non tech diver dive with two tanks of air, or nitrox, and what would the advantage be? Since we are limited by our BT/tables, why do divers use two tanks? I saw them in the dive shop connected on one cross bar to first stage but have never dove with somone using two takns/doubles. :06:

 

[simbrooks]

Steel tanks last forever with decent care, and there are always tech divers looking to switch to a different size, get less serious about their diving and move a set or 2 out of their garage, or even get out of tech diving.

Put out the word among your local dive shops that you are in the market, and contact a local tech instructor or two as well. You should be able to get an excellent set of doubles with bands, manifold, and isolator for somewhere between $500 & $800.

Do insist on a current hydro and visual or ask for a $50 discount if you will have to get the inspections.

I agree, as long as you get them in a usable state (VIP/Hydro) they are a great investment. I bought a set of HP-120's with bands and manifolds for $400, should be great for many more decades yet. They were 15 years old and i got to look inside during the VIP (just after hydro) and they were pristine! Its possible to get some gems out there, you could get a bomb of course. New are hard to get hold of unless they are Faber/OMS.

Not sure I know what doubles are but I'm thinking it's two tanks in place of one? Can a non tech diver dive with two tanks of air, or nitrox, and what would the advantage be? Since we are limited by our BT/tables, why do divers use two tanks? I saw them in the dive shop connected on one cross bar to first stage but have never dove with somone using two takns/doubles.

Doubles are two tanks, either independant/isolated/acting seperately (back or side mount) or manifolded/linked. The question isnt can a non-tech dive with them, its more a why do you want to dive with them, longer BT, gas/reg redundancy, or more gas for going deeper? Recreational divers dont need doubles (except as a practice in OW before using them in an overhead environment or just for fun). As for NDL/BT, if you use nitrox, or trimix your BT could well be extended compared to air, but most folks if they are diving them might be beyond NDL and deco diving - hence extra gas and redundancy. The tanks you saw were manifolded doubles, you would put a 1st stage on both valves, each with a 2nd stage attached, one more likely on a long hose (right side), the other on a bungeed backup (left side). As i said before, its not needed in OW, but is necessary for anything in an overhead environment, be that a cave, wreck or deco diving. People may have a variety of different sets of doubles depending on their gas needs for the dive they intend on doing - using SAC rate to work out what they need with redundancy of gas (such as rule of thirds). Its a little more involved than that, but thats the basics, IF you should ever want to go that route, please seek experienced buddies or a tech instructor to help you along

 

[mempilot]

PF,

Doubles are basically two tanks, banded together, and usually connected by a manifold. The manifold allows gas to be breathed from both tanks simultaneously. Each tank valve sports it's own 1st stage and 2nd stage regulator. This gives redundancy in the event of a failure in the 1st stage. The manifold is usually fitted with an isolation valve that allows for saving half of one's gas in the event of a failure in either tank valve.

Why do people dive doubles.

1. Redundancy - In the event of a failure that leads to the loss of gas, the diver can still effectively deal with the situation before surfacing.
2. More gas - the deeper we dive, the more gas we need to take. This is more common in technical diving where we spend more time at depth than the common al80 will provide for.

When one adds the nessessity of carrying reserve gas for the buddy OOA incident, then diving doubles deep becomes a must.

Many divers that have gone the route of tech diving end up diving doubles all the time. For me, it's about number 1 above and equipment configuration. There are very large single tanks available that when mated with an h-valve(single tank valve with two ports for independant 1st stages) provide much more gas for recreational divers coupled to some redundancy.

Hope this helps some.

Not sure I know what doubles are but I'm thinking it's two tanks in place of one? Can a non tech diver dive with two tanks of air, or nitrox, and what would the advantage be? Since we are limited by our BT/tables, why do divers use two tanks? I saw them in the dive shop connected on one cross bar to first stage but have never dove with somone using two takns/doubles. :06:

 

[pilot fish]

I agree, as long as you get them in a usable state (VIP/Hydro) they are a great investment. I bought a set of HP-120's with bands and manifolds for $400, should be great for many more decades yet. They were 15 years old and i got to look inside during the VIP (just after hydro) and they were pristine! Its possible to get some gems out there, you could get a bomb of course. New are hard to get hold of unless they are Faber/OMS.


Doubles are two tanks, either independant/isolated/acting seperately (back or side mount) or manifolded/linked. The question isnt can a non-tech dive with them, its more a why do you want to dive with them, longer BT, gas/reg redundancy, or more gas for going deeper? Recreational divers dont need doubles (except as a practice in OW before using them in an overhead environment or just for fun). As for NDL/BT, if you use nitrox, or trimix your BT could well be extended compared to air, but most folks if they are diving them might be beyond NDL and deco diving - hence extra gas and redundancy. The tanks you saw were manifolded doubles, you would put a 1st stage on both valves, each with a 2nd stage attached, one more likely on a long hose (right side), the other on a bungeed backup (left side). As i said before, its not needed in OW, but is necessary for anything in an overhead environment, be that a cave, wreck or deco diving. People may have a variety of different sets of doubles depending on their gas needs for the dive they intend on doing - using SAC rate to work out what they need with redundancy of gas (such as rule of thirds). Its a little more involved than that, but thats the basics, IF you should ever want to go that route, please seek experienced buddies or a tech instructor to help you along

Thanks. I can't see a sitaution where I, as a recreational sport diver, would need that kind of a set up, right? Thanks alot for your help. What I saw in the shop was two tanks conected in a Tee to one first stage

 

[pilot fish]

PF,

Doubles are basically two tanks, banded together, and usually connected by a manifold. The manifold allows gas to be breathed from both tanks simultaneously. Each tank valve sports it's own 1st stage and 2nd stage regulator. This gives redundancy in the event of a failure in the 1st stage. The manifold is usually fitted with an isolation valve that allows for saving half of one's gas in the event of a failure in either tank valve.

Why do people dive doubles.

1. Redundancy - In the event of a failure that leads to the loss of gas, the diver can still effectively deal with the situation before surfacing.
2. More gas - the deeper we dive, the more gas we need to take. This is more common in technical diving where we spend more time at depth than the common al80 will provide for.

When one adds the nessessity of carrying reserve gas for the buddy OOA incident, then diving doubles deep becomes a must.

Many divers that have gone the route of tech diving end up diving doubles all the time. For me, it's about number 1 above and equipment configuration. There are very large single tanks available that when mated with an h-valve(single tank valve with two ports for independant 1st stages) provide much more gas for recreational divers coupled to some redundancy.

Hope this helps some.

This sounds over my head, or diving experience. Can a person put two tanks on with a standard BC? Do you need two spaces in back for two tanks? So, the sport diver realy has no need for this kind of diving setup? If my NDL is up it doesn't matter how much more gas I have, huh?