Tank for Beginners in Cold Water?

[Scared Silly]

fx-100 3400 34.3 -0.59 -8.41
mp-100 3180+10% 38.7 -6.69 -14.71

HP100 is really what is considered a mid pressure cylinder. In fact the mfg calls it a MP100 Blue Steel Scuba - Cylinder Specs


The FX100 is 100 cuft at 3442psi. The MP100 is 100 cuft at 3498psi (3180+10%).

The difference is the MP100 has a plus rating that must be maintained with each hydro - not a big deal for the most part.

To get the same buoyancy the FX100 one would need an additional 6lbs of lead to match the buoyancy of the MP100.

At that point on land the FX100 would be 40 lbs (34+6 lbs) where as the MP100 would be 39 lbs basically the same as the FX100.

So then what is the difference? Quite simply - ditchable weight.

Edit to add if one does not care about the weight being ditchable that 6 lbs could come from a 6 lb stainless steel backplate.

 

[Tokenwiz]

HP100s are good versatile steel tanks. Should be plenty of gas for most dives. The strategy of getting LPs and overfilling them doesn't really buy much in my opinion. Even if you can only fill an HP100 to 3000 PSI then you'll still have 87cuft of gas.

 

[broncobowsher]

HP100s. Use them when I travel to socal. Also use them locally. Will use them with everything from a set of swim trunks all the way up to a drysuit. Also use them in sidemount and could use them in doubles if I wanted. So there is plenty of life in them to advance. Yes, get a pair. Not cheap, but worth it.

 

[Bob DBF]

Do not get the 3180 tanks. Those are built to lp 3aa standard and a lot heavier.

Unless you want to, I've found them to be great tanks diving wet in cold water. In the fx/hp tanks example above, you gain 4.4# tank weight on the surface but drop 6.65# of lead off your belt compared to the fx100. It's only two pounds less but it's less weight overall.

I've always refered to the Faber 3000#, 3300#, and 3180# service pressure Faber tanks as MP (mid pressure) as that was what I heard them called when they first came out.


Bob

 

[ScubaSteve858]

thanks! i was also looking at galvanized because i heard they have higher rust-proof than regular ones. before i go on a boat dive i would call them and ask if they can fill at HP but i'm just worried my options will be limited, it seemed like most of boat can only fill at 3000 or 3300. that's why i was thinking of getting 1 hp and 1 lp, how does this combo sound? although i will carry them all to my all shore diving.

I would still go with 2 HP 100 tanks. Most boats you can bring both tanks full to begin with, which is what I usually do so that I get 2 full tanks of Nitrox. Honestly, I have plenty of air for a great 2nd and 3rd dive with my HP100 filled to 3000psi. Plus, if you want to go with doubles some day you already have matching tanks.

 

[undrwater]

I don't know any shops in the Los Angeles area that will over fill low pressure tanks without a secret handshake.

Get the 3442 steel 100.

 

[EireDiver606]

In metric terms, what is a hp 100? And what is the difference between hp and lp?

 

[RyanT]

In metric, an HP 100 is 12.9 liters, call it 13. The service pressure is 232 bar.

There is some various thinking in terms of Hp and LP. I've heard some folks say that a true HP tank is one with a service pressure of 3500 psi. Typically though, most people think of an HP tank as having a service pressure of 3442 psi and a LP tank as having a service pressure of 2400 psi that can also take a 10% overfill to 2640 psi.

 

[goldenwar]

What @runsongas said. 3180s are not HP tanks and they are certainly "odd" tanks. I'm not sure I've actually seen any of them. The standard HP100 (3442 pressure) are great tanks. They remain negative when empty and they are a nice size tank for the diver of average stature. Compared to an aluminum 80 you can shed about 5 lbs of lead with the HP100. They are also a nice manageable weight on land as well.

thanks! so another vovte for faber fx-100!

 

[goldenwar]

fx-100 3400 34.3 -0.59 -8.41
hp-100 3180+10% 38.7 -6.69 -14.71

HP100 is really what is considered a mid pressure cylinder. In fact the mfg calls it a M100 Blue Steel Scuba - Cylinder Specs


The FX100 is 100 cuft at 3442psi. The HP100 is 100 cuft at 3498psi (3180+10%).

The difference is the HP100 has a plus rating that must be maintained with each hydro - not a big deal for the most part.

To get the same buoyancy the FX100 one would need an additional 6lbs of lead to match the buoyancy of the HP100.

At that point on land the FX100 would be 40 lbs (34+6 lbs) where as the HP100 would be 39 lbs basically the same as the FX100.

So then what is the difference? Quite simply - detachable weight.

Edit to add that 6 lbs of ballast could come from a 6 lbs stainless steel backplate.

thanks for the explanation! so HP-100 is a better choice if my main goal is to remove as much weight as possible. however since FX is 6lbs lighter i'm pretty much carrying the same weight anyway.