DEMA - Pressed Steel new tanks?

[pescador775]

Trust me, when they dropped the WP by 50 lbs that was the end of the 7/8 neck. It was just a lawyer trick anyway, to prevent people from using a yoke valve who would later sue over a blown O ring.

 

[C_C]

Diameter for the E7-120 should be 7.3 inches not 8.0.


Both the table and the link has been edited and updated


Thanks!

C_C

 

[scubafanatic]

....Thanks C_C for all the PST tank info! As far as further questions, I've got a couple:

1) any info on pricing?

2) any info on availability?


.......Santa needs a head's-up, ya know!


Karl

 

[ScubaDan]

Genesis
The E8-119 is the old LP95 in terms of size. The 130 is the old LP104, and the 149 is the LP120 (in terms of size, again)

The issue of mass still stands though. The 8" .vs. 7.25" cylinder requires more material, it appears, in order to maintain the desired buoyancy characteristic (and perhaps meet pressure specs as well.) As such they're quite a bit heavier.

[/B]

If you are comparing size to the old LP they are both 8"

MODEL CAPACITY O.D. LENGTH WEIGHT BOUYANCY
LP-95 95 CU.FT. 8.00 24.75 42 LBS -1.0 LBS
LP-104 104 CU.FT. 8.00 26.19 45 LBS -0.7 LBS
LP-120 120 CU.FT. 8.00 29.37 50 LBS -0.4 LBS
E8-119 3442 psi 926 15.17 8.0 24.00 39.3 -0.5 / -9.5
E8-130 3442 psi 1013 16.60 8.0 25.56 42.2 -1.8 / -11.55
E8-149 3442 psi 1158 18.97 8.0 29.37 47.5 -1.8 / -12.9

 

[Genesis]

I fail to see the point of the 8" tanks now that the "HP .vs. LP debate" is gone.

Why dive the fatter tanks when they're MUCH heavier for the same capacity and BOTH have the desired buoyancy characteristics?

There's simply no reason, unless you CAN'T tolerate the 120s due to your body size (e.g. you're just too darn short) - and in that case, I bet the HP100s give you more than enough gas (smaller person, less oxygen required!)

 

[pescador775]

Comparing Mike's data sheet with CC, should we presume that the proposed E140 designation has been replaced with E130? Makes sense to avoid potential liability; that is, if the tank actually contains 135 cf. I mean, for example, SPG's often read 100 psi too low for that reason. No one can claim they had less air than observed; or, in the case of scuba tank, less than planned for.

 

[Genesis]

My pressure gauge, by the way, does NOT read 100 psi "lower than reality." When it says I have less than 200 psi left, I really do - I can feel the inhalation effort increase as the residual pressure drops to around and below the IP!

 

[MikeFerrara]

What would going to a thinner tank do for us?
The lp 104 and I hope the e-140 has balance and buoyancy charachteristics not found in current hp tanks. They are heavy on land but in the water the weight is in the right spot and I don't need additional lead. With hp 100's we need v-weights and some divers end up head heavy. The hp 120 is too long for me and the hp 100 is too short. The 104 is just right.

 

[Genesis]

its all about mass and inertia.

20lbs is not insignificant underwater. Yes, the buoyancy characteristics mean that its not a big deal from THAT standpoint, but that's not the part that counts.

Now if you need more than 200cuft of backgas, then I agree that you need a bigger set of tanks. Ok. I "get it". But does it have to be on your back? You can carry a 40cuft stage and that only masses 15lbs (and is basically neutral empty), and if you breathe it FIRST you can drop it either in your cave or near your penetration point on a wreck, and pick it back up on the way out.

If the HP120s are too long for you - that is, if another two inches and change is too much - then I understand the point. Frankly, I don't think they are for me, but that's me. The HP100s ARE short, but that, from what I can see, is GOOD, since it means you can adjust the tank up further without hitting you in the head if you want.

A twinset of HP100s, empty, will have a buoyancy difference from the E130s of one half pound. If you need V-weights for those and not for the E130s then I have to wonder what you're doing, because half a pound isn't enough to make any material difference to anyone I know of.

As for their negative mass when full, its shift is less if you're using helium, of course.

It seems to me that PST has basically gotten rid of both the "cave fill" and most of the justification for the LP tanks, all at once.

But that's me.

 

[JamesK]

For me, 104's are almost approaching the too long range, so the HP120's are out. I also like to have a little more gas than the HP100's offer. I would rather not have to sling anything, even an AL40 if I can keep it all in my back tanks.

So while the 100's and 120's might be perfect for some, I still prefer the 104's.