Confusion

[dori fish]

I am still looking for tanks. I am confused what the difference is between a low pressure and High pressure steel tank. What uses each has different type has? Your comments, and suggestions

 

[spectrum]

Start here.

Pete

 

[Jorgy]

Assuming you can get good high pressure fills, then the HP100's seem to be a great tank..........and universally loved.......

Small diameter, easy to trim out with, relatively light top-side weight, stay negatively buoyant throughout the dive and good gas volume.........

Praised for both singles and doubles............

I dive LP95's but I got a great price on them.........

M

 

[wilsway]

How much weight are you normally diving with? One thing to consider is the different buoyancy characteristics of HP and LP steel tanks?

 

[dori fish]

What is the difference in buoyancy? I normally dive in dry with about a total of 24 lbs maybe less or more, I am still working it all out. I am tall for my age and still growing between 6 and 6' 1"

 

[spectrum]

Go to this site and compare the EMPTY BUOYANCY specifications

Pete

 

[DA Aquamaster]

Just a suggestion, but rather than hust direbting someone to "this site" or "here", list what the site or thread is, so the rest of knwo whether it is one of the old standbys or something new we want to look at without having to waste time actually clicking on the link.

 

[Ouvea]

Hi Dori Fish:

The working pressure is the pressure at which the air must be compressed to achieve a specific volume of air in the tank. Remember a one pound of feather weighs just as much as one pound of lead. So a 80cft tank at 3500psi has just as much air as an 80cft tank at 3000psi.

Get a tank that meets your volume requirements (larger lungs use more air). Get one that is negatively buoyant so you that you do not have to carry additional lead on your weight belt/bcd. Also get one that is appropriate for your physical stature (if you're 5'5, you really don't need a monstrous size tank). Conversely, don't get a 63cft tank if you're 6'7. Tanks that have working pressures above 3000psi will "usually" have DIN valves, while the lower pressure tanks will have standard K-valves. There some nifty valves tha can be converted from one design to the other.

Look at the hydro date on the tank. Don't buy a tank that has a hydro date of a few years back (old inventory). Recall that you must have a hydro static test performed every five years.

In general, Steel Tanks will cost more than Aluminum since their production costs are higher but they "usually" have more desirable characteristics. Hope this helps.

Claude

 

[dori fish]

Why would a cave diver in Florida like an lp 95 more than a hp 120, and why would a wreck diver in NY prefer an hp 120 rather than an lp 95
this is my question

 

[rstofer]

Why would a cave diver in Florida like an lp 95 more than a hp 120, and why would a wreck diver in NY prefer an hp 120 rather than an lp 95
this is my question

Because in Florida the cave divers routinely overfill their tanks - by a lot!. Not too many shops will do that, thankfully!

Just for giggles: http://edocket.access.gpo.gov/cfr_2003/octqtr/pdf/49cfr173.301.pdf
See 173.301a(c) which limits the pressure to the service pressure marked on the tank at a temperature not to exceed 70 deg F.

For the '+' rated tanks see: http://edocket.access.gpo.gov/cfr_2003/octqtr/pdf/49cfr173.302a.pdf
See 173.302a(b) which allows the 10% overfill of tanks tested and marked for the '+' rating.

Other than the 10% overfill of '+' rated tanks, no scuba tank should ever be filled higher than the marked service pressure. Among other things, it is a violation of DOT regulations.

Some interesting reading here: http://www.fillexpress.com/library/dryfills.pdf

Richard