first set of doubles for apprentice cave

[H2Andy]

well... i am looking at getting my first set of doubles so that i can become familiar
with them for about a year before going on to apprentice... so...

i was thinking of getting two hp steel 95's or perhaps 80's, since my back is not
what it used to be after i broke the L1 vertebrae...

i was also thinking of getting a Sea Elite manifold

so... what's the difference between a 200 bar and a 300 bar manifold?

and should i really get low pressure steel tanks rather than high pressure?

thanks in advance

 

[SDAnderson]

100 bar?

The difference is the number of threads on the outlet side of the valve. A 300 bar manifold has more of them. 200 bar valves often have little screw in inserts called donuts that allow the valve to be adapted for use as a yoke valve. 300 bar is a sturdier connection and will better protect the threading on your regulators.

As to your plan to spend some time getting used to doubles before you take the class, it's an excellent one. Your first dive should be shallow water with a friend: you're used to swimming like a fish but doubles will make you feel more like a turtle for awhile - and a drunken one, at that.

 

[H2Andy]

thanks

if i have yoke regulators and need the DIN-yoke adaptor, would it make a difference
whether i get 200 or 300 bar? from your post, i take it i must get a 200 bar for the
adaptor, right?

 

[Curt Bowen]

If your planning on mixing by partial pressures, I would not get HP cylinders. My suggestion would be either LP 85's or LP 95's.

HP cylinders are to hard to mix without a booster.

 

[Jason B]

Andy, usually when you get a yoke to din conversion kit it is a 300 bar.

I just started diving doubles and I have a pair of LP95's and have had zero problems as of yet.

Jason

 

[Rick Murchison]

If you use 200 bar with inserts no adapter is required - but then you don't have the advantage of having a DIN connection either.
The DIN mod to your regulators will work with either 200 or 300 bar DIN. Personally I prefer the 200 bar DIN so I can slip in an insert if I'm somewhere that doesn't have a DIN fill whip (or you can carry a DIN-to-yoke block in your kit) (my transfill whip is yoke to yoke too).
If you don't ever anticipate using a yoke fitting on the valve for any reason then the 300 bar are sturdier - but the 200 bar are far sturdier than yoke, so it's sort of like taking a Sherman tank to the local grocery rather than your car.
As for weight, 95's are almost as heavy as 104's; 85's are much lighter and my favorite unless I really need the extra gas.
Rick

 

[Divesherpa]

PST LP 80's are awesome. Great as singles for ocean diving and great as doubles for deeper stuff, light doubles, and sidemount.

Awesome!

 

[Jason B]

Another thing to consider.
A 300 bar DIN first stage will work on a 200 or 300 bar tank valve/manifold.
A 200 bar DIN first stage will only work on a 200 bar tank valve/manifold.

Jason

 

[SDAnderson]

A yoke adapter for a 200 bar DIN valve. This allows a yoke first stage to be connected to the valve. There is no such beast for a 300 bar DIN valve.

A yoke adapter for a DIN first stage.

You will not be able to use a yoke regulator on a 300 bar DIN valve.

Both Thermo and OMS have pretty good visuals on their websites:

http://www.thermovalves.com/scuba.htm

www.omsdive.com

 

[H2Andy]

excellent... thank you all