DIR- Generic HELP DECIDE - Steel HP133

[SlugLife]

we are in the DIR forum, sidemount is not typically recommended in this context

Ah, got it. I wasn't familiar with what DIR was, but just took a look. Ignore the 2nd half then.

 

[Wibble]

I'm unable to tell the difference in water or on land between lp104s and hp130s without looking for the stamp on the neck.

For the metric-addled people out here who find the gas content measurements really confusing...

What's the wet-volume metric measurement for an LP-104 and HP-130? Are these variants of a 12 litre steel cylinder?

 

[tbone1004]

For the metric-addled people out here who find the gas content measurements really confusing...

What's the wet-volume metric measurement for an LP-104 and HP-130? Are these variants of a 12 litre steel cylinder?

answered in post #6 when you asked the first time, 17L bottles.

 

[Wibble]

SCUBA Cylinder Specifications

Many issues with decimal points, but does at least show the cylinder capacity, size and weight.


A dumb question: why on earth would anyone use the low pressure versions? For example the 108 is almost the same weight as a 133 but with considerably reduced capacity. Are the LPs some legacy from the past?

 

[tbone1004]

SCUBA Cylinder Specifications

Many issues with decimal points, but does at least show the cylinder capacity, size and weight.


A dumb question: why on earth would anyone use the low pressure versions? For example the 108 is almost the same weight as a 133 but with considerably reduced capacity. Are the LPs some legacy from the past?

Use this one for Fabers since it's actually published by them
https://kaplanindustries.com/wp-con...-Faber-Steel-Cylinder-Specifications-2019.pdf

People choose LP tanks for one of 3 reasons
Predominantly from ignorance where people perpetuate a myth that they hold more than their HP equivalents
Price: they're cheaper than their HP equivalents both new and used
Buoyancy characteristics: since they're less negatively buoyant we will prefer them in warm water areas where we need the gas volume but not the weight. Faber FX133 is 1.5lbs heavier in the water than the LP108 versions. This only applies if you can get cave fills to 3600psi/250bar where they will hold the same volume of gas.

 

[elan]

A dumb question: why on earth would anyone use the low pressure versions? For example the 108 is almost the same weight as a 133 but with considerably reduced capacity. Are the LPs some legacy from the past?

Strictly speaking they are not versions, they are different tanks with somewhat close dimensions
Few reasons I can think of.

1. buoyancy characteristics work better for the diver.
2. tanks are often longer in LP version say Faber 100 and LP85 LP85 is longer
3. cheaper
4. LPs oftentimes have bigger internal volume.
5. Diving cold water - lower pressure less risk of freeflow on the first stage
6. high pressure cylinders require special permit to be renewed to have them requalified, LPs are standard 3AA. I remember there was a case with PST tanks when the future of the permit renewal was unclear

 

[tbone1004]

@elan
2. that only applies to the LP85 which is also smaller diameter. All of the other ones are indistinguishable
4. which tanks are you talking about? The LP85/FX100 are the only ones that have any noted difference and it is 12.9 vs 13.0, hardly worth paying attention to.
5. I'll have to beg to differ on that, though you can always underfill a HP cylinder
6. no different with Worthington or Faber, they'll all get renewed by the DOT. You can request personal exemptions if they don't and they do not want to deal with the quantity of those so they will continue to get renewed.

 

[DavidFL]

I am getting tired of explaining people why I use an X weight instead of a more "standard" V weight.

If you can help me understand what an X weight is, I'll try to work out on my own why it might be used?

 

[elan]

@elan
2. that only applies to the LP85 which is also smaller diameter. All of the other ones are indistinguishable
4. which tanks are you talking about? The LP85/FX100 are the only ones that have any noted difference and it is 12.9 vs 13.0, hardly worth paying attention to.
5. I'll have to beg to differ on that, though you can always underfill a HP cylinder
6. no different with Worthington or Faber, they'll all get renewed by the DOT. You can request personal exemptions if they don't and they do not want to deal with the quantity of those so they will continue to get renewed.

You are likely correct based on the recent developments and Faber being the main supplier nowadays. I might be guilty of spreading outdated info.

for different volumes I remember worthingtons HP130 being slightly smaller internal volume than lp108.
But the main driving factor for me personally was slightly different dimensions and buoyancy.
Also fills… Shops here tend to under fill HPs - “get a short fill now because I am not pumping them to 3800 or leave them overnight to cool and we will top-up” kind of thing. LPs are tend to be overfilled, oftentimes I get 3000 psi after cooling

 

[elan]

If you can help me understand what an X weight is, I'll try to work out on my own why it might be used?

its essentially a two V shaped parts that are bolted together in between tanks just below the tank band. I will try to take a pic later